Publications

TitleAbstractYear(sorted descending)
Filter
PMID
Filter
the nucleotide sequence of the bacteriophage t5 ltf gene.the nucleotide sequence of the bacteriophage t5 bg/ii-bamhi fragment (4,835 bp in length) known to carry a gene encoding the ltf protein which forms the phage l-shaped tail fibers was determined. it was shown to contain an open reading frame for 1,396 amino acid residues that corresponds to a protein of 147.8 kda. the coding region of ltf gene is preceded by a typical shine-dalgarno sequence. downstream from the ltf gene there is a strong transcription terminator. data bank analysis of the ltf p ...19957789514
structure, characterization, and expression of the rat oxytocin receptor gene.the multiple hormonal and neurotransmitter functions of the nonapeptide oxytocin are mediated by specific oxytocin receptors (otrs). in most target tissues, the number of otrs is strongly regulated. specifically, in the uterus, a dramatic otr upregulation precedes the onset of parturition. to study the molecular mechanisms underlying otr regulation, we have isolated and characterized recombinant bacteriophage lambda embl3 genomic clones containing the rat otr gene, using sequence information der ...19957816817
involvement of the host initiator function dnaa in the replication of coliphage lambda.we demonstrate that the initiation of coliphage lambda dna replication is dependent on the host initiator function dnaa, provided that the lambdoid prophage rac is absent. presence of rac compensated the absence of dnaa function, causing initiation of replication. in dnaats rac+ cells at 43 degrees, most of parental phage dna molecules, after one round of theta replication, switched to a replication with features of the sigma mode and produced progeny at high yield. initiation of replication of ...19957789753
mutational analysis of the prohead binding domain of the large subunit of terminase, the bacteriophage lambda dna packaging enzyme.terminase, the dna packaging enzyme of bacteriophage lambda, is made up of two subunits, gpnul and gpa, the products of the nu1 and a genes. the activities of terminase include dna binding, cos cleavage and prohead binding. specificity domains within the structure of terminase have previously been defined by genetic studies of lambda-21 hybrids. the prohead binding domain of terminase is localized to the last 32 amino acid residues of gpa. mutations in the prohead binding domain of gpa were cons ...19957799431
on the clustered exchanges of the recbcd pathway operating on phage lambda.lytic cycle crosses of red- gam- phage lambda were conducted in rec+ escherichia coli carrying one or another plasmid with homology to lambda. lambda x lambda recombinants and lambda x plasmid recombinants were formed by recbcd-mediated recombination. we showed previously that the act of recombining with a plasmid alters the disposition of selected lambda x lambda exchanges. this work reports that the relationships between the lambda x plasmid and the lambda x lambda exchanges is unaltered by th ...19957768427
specific interaction of terminase, the dna packaging enzyme of bacteriophage lambda, with the portal protein of the prohead.terminase, the bacteriophage lambda dna packaging protein, is a heteromultimer of two subunits, gpnu1 and gpa, the products of genes nu1 and a, resp. phage 21 is a lambdoid phage that produces a terminase similar to that of lambda terminase, the subunits of 21 terminase, gp1 and gp2, have the same domain structures of their lambda analog, gpnu1 and gpa, respectively. the lambda and 21 terminases have different dna binding and prohead binding specificities. when the c-terminal 32 amino residues o ...19957799432
identification of related genes in phages phi 80 and p22 whose products are inhibitory for phage growth in escherichia coli ihf mutants.bacteriophage lambda grows in both ihf+ and ihf- host strains, but the lambdoid phage phi 80 and hybrid phage lambda (qsrrha+)80 fail to grow in ihf- host strains. we have identified a gene, rha, in the phi80 region of the lambda(qsrrha+)80 genome whose product, rha, inhibits phage growth in an ihf- host. a search of the genbank database identified a homolog of rha, orf201, a previously identified gene in phage p22, which similarly inhibits phage growth in ihf- hosts. both rha and orf201 contain ...19957768817
assembly of functional bacteriophage lambda virions incorporating c-terminal peptide or protein fusions with the major tail protein.the tolerance of bacteriophage lambda morphogenesis for c-terminal additions to the tail tube major protein subunit (the v gene product; gpv) has been investigated. a second modified copy of the lambda v gene, either within a novel phage vector itself or plasmid-borne, was expressed during phage growth. high-level substitution of wild-type gpv by modified gpv bearing a basic c-terminal peptide sequence (rrasv; a target site for camp-dependent protein kinase) was possible using multiple repeats o ...19957752219
restriction, methylation and ligation of 5-hydroxymethyluracil-containing dna.oxidation of dna and its components can cause genetic mutations and chromosomal instability. these changes have generally been implicated in aging. oxidation of the methyl group of thymidine residues in dna is known to result in the formation 5-hydroxymethyl-2'-deoxyuridine (5hmdurd). we have utilized bacillus subtilis phage spo1 dna as a model of oxidatively damaged dna. in this phage, all thymine (thy) residues are replaced by 5-hydroxymethyluracil (5hmura), but the species is naturally devoid ...19957862175
the pclip plasmids: versatile cloning vectors based on the bacteriophage lambda origin of replication.a series of general-purpose plasmid vectors based on the phage lambda origin of replication (ori) has been constructed. each vector consists of a backbone plasmid encoding chloramphenicol resistance (cmr) and containing a unique haeii site into which the lacz alpha-complementing multiple cloning site (mcs) region of an established vector was inserted. to increase the cloning potential of the inserted mcs, superfluous restriction sites in the backbone were removed by a variety of techniques. the ...19957883185
frequent t:a-->g:c transversions in x-irradiated mouse cells.ionizing radiation is a known carcinogen and teratogen. however, the point mutations produced by ionizing radiation in mammalian cells have not been fully characterized. determination of a characteristic spectrum of x-ray-induced mutations in mammalian cells could provide clues to cellular repair processes and could serve as a marker of individual exposure to radiation. mouse fibroblasts containing in their genome multiple copies of a recoverable lambda phage shuttle vector were used to detect a ...19957834808
repair of phage lambda dna damaged by near ultraviolet light plus 8-methoxypsoralen.treatment of phage lambda with 8-methoxypsoralen plus near ultraviolet light (puva) and its subsequent infection and growth on various mutant and non-mutant hosts were investigated. a number of escherichia coli dna repair-deficient mutants, particularly those deficient in genes producing proteins known to participate in interstrand crosslink repair, were used as hosts to assess the roles of these gene products in the activation of phage affected by puva. results show that puva, uvra, uvrd, reca, ...19957897361
cloning and characterization of the hrpa gene in the terc region of escherichia coli that is highly similar to the deah family rna helicase genes of saccharomyces cerevisiae.during the course of systematic nucleotide sequence analysis of the terc region of e.coli k-12 by using the ordered lambda phage clones, we found the presence of a gene, termed hrpa, that showed a high degree of sequence similarity to the prp2, prp16 and prp22 genes of saccharomyces cerevisiae. the products of these yeast genes are known to play their roles in mrna splicing, and belong to a group of proteins collectively called the deah family. the hrpa gene is the first example of a deah family ...19957899078
asparagine-linked glycosylation in schizosaccharomyces pombe: functional conservation of the first step in oligosaccharide-lipid assembly.the gene gpt encoding uridine diphosphate n-acetyl-d-glucosamine:dolichol phosphate n-acetylglucosaminylphosphoryltransferase (l-g1pt) was isolated by screening a schizosaccharomyces pombe genomic dna library in lambda phage under low-stringency hybridization using the saccharomyces cerevisiae gene alg7 as probe. sequencing 2.4 kb of s. pombe dna revealed a 1338-bp open reading frame (orf) encoding a hydrophobic protein of 446 amino acids with a predicted molecular weight of 49,852. the s. pombe ...19957893167
primary structure and functional analysis of the lysis genes of lactobacillus gasseri bacteriophage phi adh.the lysis genes of the lactobacillus gasseri bacteriophage phi adh were isolated by complementation of a lambda sam mutation in escherichia coli. nucleotide sequencing of a 1,735-bp dna fragment revealed two adjacent coding regions of 342 bp (hol) and 951 bp (lys) in the same reading frame which appear to belong to a common transcriptional unit. proteins corresponding to the predicted gene products, holin (12.9 kda) and lysin (34.7 kda), were identified by in vitro and in vivo expression of the ...19957836307
abundance, variability and chromosomal location of microsatellites in wheat.the potential of microsatellite sequences as genetic markers in hexaploid wheat (triticum aestivum) was investigated with respect to their abundance, variability, chromosomal location and usefulness in related species. by screening a lambda phage library, the total number of (ga)n blocks was estimated to be 3.6 x 10(4) and the number of (gt)n blocks to be 2.3 x 10(4) per haploid wheat genome. this results in an average distance of approximately 270 kb between these two microsatellite types combi ...19957854317
the old exonuclease of bacteriophage p2.the old protein of bacteriophage p2 is responsible for interference with the growth of phage lambda and for killing of recbc mutant escherichia coli. we have purified old fused to the maltose-binding protein to 95% purity and characterized its enzymatic properties. the old protein fused to maltose-binding protein has exonuclease activity on double-stranded dna as well as nuclease activity on single-stranded dna and rna. the direction of digestion of double-stranded dna is from 5' to 3', and dige ...19957836278
genomic structure of the mouse delta opioid receptor gene.using mouse delta opioid receptor (dor) cdna sequence to probe genomic libraries in bacteriophage lambda and p1 vectors, clones traversing the entire dor coding sequence and 5' and 3' flanking regions were isolate. genomic sequence encoding mature dor message, including 5' and 3' untranslated sequence, is divided by two introns of 26 kb and 3 kb, resulting in the gene occupying 32 kb of chromosomal dna. multiple putative transcription initiation sites were located, by rnase protection assay, in ...19957857252
display of peptides and proteins on the surface of bacteriophage lambda.the display of peptides or proteins on the surface of viruses is an important technology for studying peptides or proteins and their interaction with other molecules. here we describe a display vehicle based on bacteriophage lambda that incorporates a number of features distinct from other currently used display systems. fusions of peptides or protein domains have been made to the amino terminus of the 11-kda d protein of the lambda capsid. these fusions assemble onto the viral capsid and appear ...19957878027
characterization of an infectious molecular clone of human t-cell leukemia virus type i.an infectious molecular clone of human t-cell leukemia virus type i (htlv-i) was derived from an htlv-i-transformed rabbit t-cell line, rh/k30, obtained by coculture of rabbit peripheral blood mononuclear cells (pbmc) with the human htlv-i-transformed cell line mt-2. the rh/k30 cell line contained two integrated proviruses, an intact htlv-i genome and an apparently defective provirus with an in-frame stop codon in the env gene. a genomic dna fragment containing the intact htlv-i provirus was clo ...19957884847
identification of a cdna for ssrp1, an hmg-box protein, by interaction with the c-myc oncoprotein in a novel bacterial expression screen.we describe a system for screening cdna expression libraries in escherichia coli based on protein-protein interactions. the system utilizes fusion proteins containing the dna binding domain of the lambda phage cl repressor and a heterologous dimerization domain, which is the target of the screen. such chimeric proteins were functional as transcriptional repressors in e.coli; function was dependent on the presence of the heterologous dimerization domain, and function of the chimeras was disrupted ...19957862532
enhanced activity of the bacteriophage lambda pl promoter at low temperature.the response of the early phage lambda pl promoter to temperature was investigated. experiments with lacz reporter gene fusions demonstrated that the activity of the phage lambda pl promoter is inversely dependent on temperature. the bacterial dna-binding protein integration host factor (ihf) further enhances lambda pl promoter activity at low temperature, although no apparent changes in the cellular level of ihf protein were observed at the different temperatures. ihf protein binds dna in vitro ...19957892244
transcriptional activation of the origin of coliphage lambda dna replication is regulated by the host dnaa initiator function.the initiator of phage lambda dna replication, the lambda o protein, is considered to be an analogue of the initiator of dna replication (dnaa) of its host, escherichia coli. both specifically recognize their origins of replication, ori lambda and oric, respectively, and organize the assembly of specific replication complexes. however, dnaa has an additional activation function, acting on oric-proximal dnaa-boxes, and regulating transcription initiated at promoters in and around oric. here, we d ...19957867947
inhalation of benzene leads to an increase in the mutant frequencies of a laci transgene in lung and spleen tissues of mice.the goal of this study was to determine if inhalation of benzene leads to an increase in the mutant frequencies in the tissues of male c57bl/6 mice. mutant frequencies were measured using a previously described assay in which bacteriophage lambda laci transgenes are rescued from mouse genomic dna as infectious phage and scored for their laci phenotype. eight experimental mice were exposed to a target concentration of 300 ppm of benzene for 6 h/day x 5 days/week x 12 weeks, and eight control mice ...19957870081
bor gene of phage lambda, involved in serum resistance, encodes a widely conserved outer membrane lipoprotein.bor is one of two recently identified genes of phage lambda which are expressed during lysogeny and whose products display homology to bacterial virulence proteins. bor is closely related to the iss locus of plasmid coiv,i-k94, which promotes bacterial resistance to serum complement killing in vitro and virulence in animals. bor has a similar in vitro effect. we show here that the bor gene product is a lipoprotein located in the escherichia coli outer membrane. we also find that antigenically re ...19957868598
protection of coliphage lambda o initiator protein from proteolysis in the assembly of the replication complex in vivo.we have shown previously that, in contrast to the free coliphage lambda o initiator protein rapidly degraded by clpp/clpx protease, the lambda present in the replication complex (rc) is protected from proteolysis. now we asked at which step of the pathway of rc assembly in vivo does the stabilization of lambda o occur. in accordance with the in vitro established order we found that lambda p and dnab helicase functions are, but those of dnaj and grpe chaperones are not, required for the protectio ...19957871725
investigations of the interactions of saccharides with the lysozyme from bacteriophage lambda.the bacteriophage lambda r gene has been isolated into an escherichia coli expression system and the r gene product, a lysozyme, has been overexpressed and purified to homogeneity using an efficient purification procedure. a turbidimetric assay utilizing chloroform-treated e. coli cells has been optimized to assess the bacteriolytic activity of the purified enzyme. using this assay, oligomers of beta (1 --> 4) n-acetyl-d-glucosamine at high concentrations were shown to inhibit lysozyme but were ...19957873585
induction and processing of promutagenic o4-ethylthymine lesion in specific gene segments of plasmid dna.high affinity antibodies were used for the quantitative assessment of the miscoding o4-ethylthymine (o4-etthy) base lesion in nanogram amounts of membrane transblotted restriction fragments of enu treated dna. the polyclonal antibody (tb3) specifically recognized attomoles of the alkylation adducts in modified dna with no cross-reactivity to an excess of unmodified dna. the sensitivity of the immuno-quantitative method was determined to be in the range of 76 attomoles to 2.43 fmol, corresponding ...19957873601
modulation of the atpase activity of the molecular chaperone dnak by peptides and the dnaj and grpe heat shock proteins.previous studies have demonstrated that the escherichia coli dnak, dnaj, and grpe heat shock proteins participate in the initiation of bacteriophage lambda dna replication by mediating the required disassembly of a preinitiation nucleoprotein structure that is formed at the phage replication origin. to gain some understanding in a simpler system of how the dnaj and grpe cochaperonins influence the activity of dnak, we have examined the effect of the cochaperonins on the weak intrinsic atpase act ...19957876226
mutagenesis by 8-methoxypsoralen and 5-methylangelicin photoadducts in mouse fibroblasts: mutations at cross-linkable sites induced by offoadducts as well as cross-links.psoralens are used clinically in the treatment of several skin diseases, including psoriasis, vitiligo, and cutaneous t cell lymphoma. however, psoralen treatment has been associated with an increased risk of squamous cell carcinoma of the skin. to elucidate molecular events that may play a role in the psoralen-related carcinogenesis, we examined psoralen-induced mutagenesis in a mouse fibroblast cell line carrying a recoverable, chromosomally integrated lambda phage shuttle vector. using the su ...19957882323
isolation and structural analysis of the 5' flanking region of the gene encoding the human glucagon receptor.the gene encoding the human glucagon receptor, including several kb of upstream sequence, was isolated from a bacteriophage lambda fix ii library constructed from human placental dna. we report here the novel sequence of the 5' flanking region of the gene, the identification of a previously unreported intron of 5 kb, and the identification of the transcription start point of the glucagon receptor-specific transcript, which estimates the length of the first exon to be 300 bp.19957887948
primary products of break-induced recombination by escherichia coli rece pathway.alternative models for break-induced recombination predict different distributions of primary products. the double-stranded break-repair model predicts a noncrossover product and equimolar amounts of two crossover products. the one-end pairing model predicts two crossover products, but not necessarily in equimolar amounts, and the single-stranded annealing model predicts deletion of the fragment between the pairing sequences. depending on the structure of the recombining substrate(s) and the nat ...19957896689
lambda foo: a lambda phage vector for the expression of foreign proteins.this work describes a lambda phage expression system, lambda foo, that produces foreign proteins fused to the surface of the virus particle. the lambda foo vector has multiple cloning sites for the insertion of a foreign dna fragment and color selection for recombinants. foreign proteins are fused to the c terminus of a truncated phage tail protein, pv, by a peptide linker. conditional chain termination allows the assembly and fusion of multisubunit proteins. we have attached the complete escher ...19948058794
biochemical characterization of p22 phage-modified escherichia coli recbcd enzyme.the biochemical properties of phage p22 abc-modified recbcd enzyme from escherichia coli have been examined. recbcd purified from a cell that expresses abc (anti-recbcd) contains all three recbcd subunits and the 11.6-kda abc protein in equal stoichiometric amounts. abc depresses the rate of recbcd double-stranded dna exonuclease, helicase, and atpase activities about 3-4-fold, yet it has no effect on the rate of the single-stranded dna exonuclease activity. abc induces a slight increase in the ...19948077199
direct observation of tube-like motion of a single polymer chain.tube-like motion of a single, fluorescently labeled molecule of dna in an entangled solution of unlabeled lambda-phage dna molecules was observed by fluorescence microscopy. one end of a 16- to 100-micrometer-long dna was attached to a 1-micrometer bead and moved with optical tweezers. the molecule was stretched into various conformations having bends, kinks, and loops. as the polymer relaxed, it closely followed a path defined by its initial contour. the relaxation time of the disturbance cause ...19948171335
the cellular proteins that bind specifically to the epstein-barr virus origin of plasmid dna replication belong to a gene family.this laboratory has previously reported that a tumor-promoting phorbol ester, phorbol 12-myristate 13-acetate ("12-o-tetradecanoylphorbol 13-acetate"), induces bjab cells, a burkitt lymphoma cell line, to express cellular proteins that bind to the origin of plasmid dna replication (orip) of epstein-barr virus. these orip-binding proteins interfere with the ebv-encoded nuclear antigen ebna-1, which binds to orip in raji cells. to further characterize these proteins, a lambda phage expression cdna ...19948146198
streptomyces lividans 66 contains a gene for phage resistance which is similar to the phage lambda ea59 endonuclease gene.the dna of wild-type streptomyces lividans 66 is degraded during electrophoresis in buffers containing traces of ferrous iron. s. lividans zx1, a mutant selected for resistance to dna degradation, simultaneously became sensitive to phi hau3, a wide-host-range temperate bacteriophage. a dna fragment conferring phi hau3 resistance was cloned; it contains a phage resistance gene whose deduced amino acid sequence is similar to the phage lambda ea59 endonuclease. the s. lividans phi hau3 resistance d ...19948052130
conjugative transposition: tn916 integrase contains two independent dna binding domains that recognize different dna sequences.transposition of the conjugative transposon tn916 requires the activity of a protein, called int, which is related to members of the integrase family of site-specific recombinases. this family includes phage lambda integrase as well as the cre, flp and xerc/xerd recombinases. different proteins, consisting of fragments of tn916 int protein fused to the c-terminal end of maltose binding protein (mbp) were purified from escherichia coli. dnase i protection experiments showed that mbp-int proteins ...19948156992
structure of the sea urchin hatching enzyme gene.the sea urchin embryo develops from an encased to a free-living larva by secreting at an early stage the hatching enzyme, a metalloprotease which hydrolyses a protective envelope derived from the egg extracellular matrix. genomic clones containing the entire hatching enzyme gene were isolated from a lambda phage sea urchin library and the complete sequence of the transcription unit was determined. the hatching enzyme gene spans 6.3 kb and comprises 9 exons. the exon/intron organization of the ha ...19948112336
restriction mapping of phage lambda vectors using non-radioactive methods.in order to take advantage of non-radioactive methods, we have developed two plasmids (p lambda le and p lambda re) for mapping restriction sites of long inserts cloned in phage lambda vectors. these plasmids are constructed by cloning the left 402-bp and right 560-bp phage lambda genome ends, respectively. to map restriction sites, the cloned sequences in p lambda le and p lambda re are labeled with digoxygenin and hybridized to partially digested lambda dna. the ladder of bands detected with t ...19948200536
the 9-kda calbindin gene of rousettus aegyptiacus: its identification and isolation from a genomic library.a genomic library of the fruit bat (rousettus aegyptiacus) was constructed in lambda phage gt11. the titre of the library was determined to be 2 x 10(5) pfu/ml. the genomic library was amplified and the titre of the amplified library increased 300-fold to 7 x 10(7) pfu/ml. the library was screened by in situ hybridization techniques using a fragment of the mouse 9-kda calbindin cdna as a probe. screening of 10(5) plaques yielded a positive clone. three additional rounds of screening were perform ...19948205389
structure of the bovine lactoferrin-encoding gene and its promoter.lactoferrin (lf), a ferric ion (fe3+)-binding glycoprotein, is found most notably in milk, probably to mediate protection against microbial infection of the mammary gland. based on an initial isolation and sequencing of a complete cdna of the bovine lf gene (blf), the complete gene was obtained from genomic libraries on five overlapping phage lambda embl3 clones. a detailed restriction map and the complete exon/intron structure of the gene are presented, together with 1 kb of sequence data of th ...19948206385
dynamic properties of nucleic acids in biosupramolecular systems, as studied by 31p nmr.the dynamic properties of nucleic acids in five different types of intact supramolecular systems, namely, chicken erythrocyte chromatin, the wild type and a deletion mutant of the lambda phage, lipid-containing phage pm2, and alteromonas espejiana ribosomes, were investigated by means of 31p solid-state nmr. the nucleic acids in the different supramolecular systems showed unique dynamic properties, which are closely connected with their functions. the total anisotropy of the phosphorus chemical ...19948206876
adsorption of bacteriophage lambda on the lamb protein of escherichia coli k-12: point mutations in gene j of lambda responsible for extended host range.lamb is the cell surface receptor for bacteriophage lambda. lamb missense mutations yielding resistance to lambda group in two classes. class i mutants block the growth of lambda with the wild-type host range (lambda h+) but support the growth of one-step host range mutants (lambda h). class ii mutants block lambda h but support the growth of two-step host range mutant (lambda hh*) phages. to identify amino acid residues in the j protein (the tail fiber of phage lambda) responsible for the exten ...19948106335
escherichia coli-salmonella typhimurium hybrid nusa genes: identification of a short motif required for action of the lambda n transcription antitermination protein.the escherichia coli nusa gene, nusaec, encodes an essential protein that influences transcription elongation. derivatives of e. coli in which the salmonella typhimurium nusa gene, nusast, has replaced nusaec are viable. thus, nusast can substitute for nusaec in supporting essential bacterial activities. however, hybrid e. coli strains with the nusast substitution do not effectively support transcription antitermination mediated by the n gene product of phage lambda. we report the dna sequence o ...19948113180
mapping of the gene coding for a paraneoplastic encephalomyelitis antigen (hud) to human chromosome site 1p34.a cdna clone coding for a human brain protein (hud), which is highly homologous to the drosophila neuronal determination protein elav and elicits antibody formation in a high proportion of patients with paraneoplastic encephalomyelitis, was used to isolate a lambda phage recombinant clone, including a large fragment of the relevant human genomic region. the fragment proved to be an efficient probe for the precise subregional mapping of the gene by molecular in situ hybridization onto extended hu ...19948222755
bipartite dna recognition by the human oct-2 pou domain: pous-specific phosphate contacts are analogous to those of bacteriophage lambda repressor.the pou motif defines a family of eukaryotic transcription factors broadly involved in tissue-specific gene expression and developmental regulation. the motif contains two dna-binding domains: an n-terminal pou-specific domain (pous) and c-terminal homeodomain (pouhd). surprisingly, pous has recently been found to be similar in structure to helix-turn-helix (hth) domains of phage repressor and cro proteins [assa-munt, n., mortishire-smith, r., aurora, r., herr, w., & wright, p.e. (1993) cell 73, ...19948117693
dna stretching on functionalized gold surfaces.we describe a method for anchoring bacteriophage lambda dna by one end to gold by au-biotin-streptavidin-biotin-dna bonds. dna anchored to a microfabricated au line could be aligned and stretched in flow and electric fields. the anchor was shown to resist a force of at least 11 pn, a linkage strong enough to allow dna molecules of chromosome size to be stretched and aligned.19948127690
identification of partial complementary dna clones encoding a 59-kd protein with characteristics of a unique oncofetal antigen.oncofetal antigens (ofas) are conserved tumor-associated autoantigens or transplantation antigens present on the surface of all major classes of rodent and human tumors and on midgestational fetal cells but not on normal neonatal or adult human and rodent tissues. a syngeneically derived monoclonal antibody, mab-115, recognizes murine ofas of 44 and 200 kd in molecular mass.19948133535
new lambda and plasmid vectors for expression cloning in mammalian cells.this report describes the construction of a new family of lambda phage and plasmid cloning vectors. lambda gdst3/t7 allows cdna insertion up to 14 kb; it is derived from lambda nm1151 by the insertion of a multiple cloning site containing eight unique restriction sites. the two asymmetrical sfii sites are flanked by the t3 and t7 promoters for direct sequencing and in vitro transcription/translation. the same multiple cloning site is also present in both orientations in the eukaryotic expression ...19948136127
genetic selection for mutations that impair the co-operative binding of lambda repressor.bacteriophage lambda repressor binds co-operatively to adjacent pairs of dna target sites. a novel combination of positive genetic selections, involving two different operon fusions derived from p22 challenge phages, was used to isolate mutant lambda repressors that have lost the ability to bind co-operatively to tandem sites yet retain the ability to bind a strong, single site. these cb (co-operative binding) mutations result in 10 different amino acid changes, which define eight residues in th ...19948152379
cold-sensitive phenotype of escherichia coli cells harboring a plasmid carrying the kil gene of phage lambda brought under control of ci857 gene promoters.a plasmid (pi-14), containing part of the phage lambda control region (ecori-d fragment of lambda ci857) with a large deletion between genes rex and kil, confers a cold-sensitive (cs) phenotype on the host bacteria, whereas the parent plasmid (pmm200) without the deletion made the host bacteria (escherichia coli strain doo) high-temperature sensitive. this phenomenon could be explained on the basis of the sequence analysis of the deletion. upon this deletion, the lambda kil gene, which was origi ...19948163171
an altered-specificity mutation in a human pou domain demonstrates functional analogy between the pou-specific subdomain and phage lambda repressor.the pou motif, conserved among a family of eukaryotic transcription factors, contains two dna-binding domains: an n-terminal pou-specific domain (pous) and a c-terminal homeodomain (pouhd). surprisingly, pous is similar in structure to the helix-turn-helix domains of bacteriophage repressor and cro proteins. such similarity predicts a common mechanism of dna recognition. to test this prediction, we have studied the dna-binding properties of the human oct-2 pou domain by combined application of c ...19948171007
variations in base pair composition and associated long-range correlations in dna sequences--computer simulation results.recently, the possible occurrence of long-range correlations between nucleotides in dna sequences of living organisms has excited considerable interest. of particular importance is the claim that only intron-containing sequences exhibit these correlations. different investigations, however, have disproved the claimed difference between intron-containing and intron-less dna sequences. moreover, very recent investigations pointed out that the long-range correlations appear only if relatively large ...19948110832
selective binding of escherichia coli rna polymerase to topoisomers of minicircles carrying the tac16 and tac17 promoters.we have studied the effect of dna supercoiling on open complex formation by escherichia coli rna polymerase at the tac16 and tac17 promoters. a two-dimensional gel retardation assay was used to measure the relative rate of association between rna polymerase and the tac promoters on individual topoisomers. plasmid dnas usually have several promoters that complicate the analysis of rna polymerase binding to only one of them. we avoided this problem by using minicircles of dna carrying only a singl ...19948175785
a new procedure for the purification of the bacteriophage lambda terminase enzyme and its subunits. properties of gene product a, the large subunit.new methods for the purification of highly active bacteriophage lambda terminase holoenzyme, and its individual subunits, gene products (gp) a and gpnu1, have been developed. these methods are rapid, simple, reproducible, and give high yields of unaggregated protein from small volumes of culture. the procedures involve fractionation of extracts of escherichia coli strains harboring plasmids engineered to overproduce the respective proteins. all purified proteins exist as monomers or dimers at mo ...19948175792
determining the dna sequence elements required for binding integration host factor to two different target sites.binding sites for the escherichia coli protein integration host factor (ihf) include a set of conserved bases that can be summarized by the consensus sequence watcaannnnttr (w is da or dt, r is da or dg, and n is any nucleotide). however, additional 5'-proximal bases, whose common feature is a high da+dt content, are also thought to be required for binding at some sites. we examine the relative contribution of these two sequence elements to ihf binding to the h' and h1 sites in attp of bacteriop ...19948188600
the in vitro endonuclease activity of gene product a, the large subunit of the bacteriophage lambda terminase, and its relationship to the endonuclease activity of the holoenzyme.the reaction requirements and kinetic properties of the in vitro endonuclease activity of the bacteriophage lambda terminase and its large subunit, gene product (gp) a, have been analyzed. optimal cleavage reaction activity for both proteins requires mg2+, a ph between 8.5 and 9.0, and is enhanced by atp or atp analogs. under these conditions both terminase and gpa generate aberrant nicks in and around cosn. optimal nicking specificity of terminase is observed under conditions of 50-100 mm salt, ...19948175793
a role for residue 151 of lamb in bacteriophage lambda adsorption: possible steric effect of amino acid substitutions.lamb is the cell surface receptor for bacteriophage lambda. lamb missense mutations yielding resistance to lambda have been previously grouped in two classes. class i mutants block growth of lambda with wild-type host range (lambda h+) but support growth of one-step extended-host-range mutants (lambda h). class ii mutants block lambda h but support growth of two-step extended host range mutants (lambda hh*). while class i mutations occur at 11 different amino acid sites, in five distinct portion ...19948195074
isolation and characterization of point mutations in the escherichia coli grpe heat shock gene.the escherichia coli grpe gene (along with dnak, dnaj, groel, and groes) was originally identified as one of the host factors required for phage lambda growth. the classical grpe280 mutation was the only grpe mutation that resulted from the initial screen and shown to specifically block the initiation of lambda dna replication. here we report the isolation of several new grpe missense mutations, again using phage lambda resistance as a selection. all mutants fall into two groups based on their t ...19947961459
stability of escherichia coli transcription complexes near an intrinsic terminator.transcription complexes containing escherichia coli rna polymerase terminate rna synthesis in response to intrinsic (rho-independent) terminators encoded in the dna template. this type of termination involves the formation of a hairpin structure in the nascent rna, leading to release of the rna and polymerase from the dna template. in this paper we show that rna release occurs only within a zone extending over six template positions of the tr2 terminator of phage lambda. the upstream end of this ...19947966320
characterization of broadly pleiotropic phenotypes caused by an hfq insertion mutation in escherichia coli k-12.the region immediately downstream from the miaa trna modification gene at 94.8 min contains the hfq gene and the hfla region, which are important in the bacteriophage q beta and lambda life cycles. the roles of these genes in bacteria remain largely unknown. we report here the characterization of two chromosomal hfq insertion mutations. an omega (omega) cassette insertion near the end of hfq resulted in phenotypes only slightly different from the parent, although transcript mapping demonstrated ...19947984093
helix-capping interaction in lambda cro protein: a free energy simulation analysis.the stability mutant tyr-26-->asp was studied in the cro protein from bacteriophage lambda using free energy molecular dynamics simulations. the mutant was calculated to be more stable than the wild type by 3.0 +/- 1.7 kcal/mol/monomer, in reasonable agreement with experiment (1.4 kcal/mol/monomer). moreover, the aspartic acid in the mutant was found to form a capping interaction with the amino terminus of the third alpha-helix of cro. the simulations were analyzed to understand better the sourc ...19947984627
bacteriophage lambda n-dependent transcription antitermination. competition for an rna site may regulate antitermination.bacteriophage lambda controls the expression of its early genes in a temporal manner by a series of transcription termination and antitermination events. this antitermination requires the lambda n protein as well as host proteins called nus, and cis-acting sites called nut. following transcription of the nut site, n and nus proteins bind to the nut rna and modify the transcription complex to a termination-resistant form. the nut site is a composite of at least two components; one is the boxb hai ...19948107107
dna conformational changes associated with the cooperative binding of ci-repressor of bacteriophage lambda to or.the ci repressor protein (ci) maintains bacteriophage lambda in the lysogenic state in infected escherichia coli cells by binding cooperatively to three tandemly repeated sequences comprising the right operator (or). cooperative interactions occur between alternate pairs of ci dimers bound to adjacent sites. although crystallographic studies have revealed the structure of the dna in the 92 amino acid residue amino-terminal fragment-ol1 complex, the structure of the dna within the or-ci complex w ...19947990137
neither absence nor excess of lambda o initiator-digesting clpxp protease affects lambda plasmid or phage replication in escherichia coli.owing to rapid proteolysis of the coliphage lambda-coded initiator protein, lambda o, this protein is considered to carry a rate-limiting step in lambda dna replication. the discovery of clpxp protease responsible for lambda o protein turnover allowed an opportunity to verify this hypothesis. however, neither absence nor excess of this protease significantly affected the transformation efficiency and copy number of lambda plasmid, or the kinetics of the lambda phage growth. these results are als ...19947997163
cloning and expression of putative cytotonic enterotoxin-encoding genes from aeromonas hydrophila.a genomic library from a diarrheal isolate, ssu, of aeromonas hydrophila was constructed in a cosmid vector, phc79, and in bacteriophage lambda embl3. cell lysates from various escherichia coli clones containing the recombinant cosmid were examined for their ability to elongate chinese hamster ovary (cho) cells, which is a typical enterotoxic response. based on restriction analysis, a 4.0-kb sali dna fragment from one of the clones that exhibited enterotoxic activity was subcloned into a bacteri ...19948112594
cloning and sequencing of the secy homolog from coryneform bacteria.a conserved domain of the secy genes from bacillus subtilis, mycoplasma capricolum and escherichia coli was used to design degenerate oligodeoxyribonucleotides. these synthetic dna sequences were used to screen a lambda library of brevibacterium flavum mj233. a 1.5-kb kpni fragment of a recombinant lambda phage containing the secy homology from br. flavum mj233 was subsequently subcloned into plasmid puc118. the complete nucleotide (nt) sequence of the cloned fragment indicated that the deduced ...19948112597
an additional role of transcriptional activation of ori lambda in the regulation of lambda plasmid replication in escherichia coli.initiation of replication of plasmids derived from coliphage lambda in vivo is dependent on transcription at or near the replication origin, ori lambda. however, this transcriptional activation is dispensable for lambda plasmid dna replication reconstituted in vitro from purified lambda and escherichia coli proteins. it was proposed previously that histone-like protein hu interferes with the assembly or function of the pre-primosomal complex, and transcription at or near ori lambda abolishes hu- ...19947999116
optimal sequence selection in proteins of known structure by simulated evolution.rational design of protein structure requires the identification of optimal sequences to carry out a particular function within a given backbone structure. a general solution to this problem requires that a potential function describing the energy of the system as a function of its atomic coordinates be minimized simultaneously over all available sequences and their three-dimensional atomic configurations. here we present a method that explicitly minimizes a semiempirical potential function simu ...19948016069
a pcr differential screening method for rapid isolation of clones from a cdna library.we have developed a new two-step differential screening method that allows the rapid isolation of induced or suppressed pure gene clones from a lambda phage cdna library. this method involves a primary differential screening step and a pcr differential screening step. from the primary screening step, impure pools of positive cdna clones are obtained. each pool of clones is then amplified directly by pcr using two primers flanking the cloning site in the vector. the pcr products are run on two du ...19948024788
structure of the human type iv collagen col4a5 gene.the complete exon size and distribution pattern of the human alpha 5(iv) collagen gene col4a5 has been determined. seventeen genomic lambda phage clones, eight of which have been described previously (zhou, j., hostikka, s.l., chow, l.t., and tryggvason, k. (1991) genomics 9, 1-9), spanning about 160 kilobases of dna contained 140 kilobases of the gene itself. the clones covered the entire gene with the exception of exons 2 and 37 and their flanking regions so that the exact gene size could not ...19948120014
tail length determination in bacteriophage t4.this report identifies a protein that regulates tail length in bacteriophage t4. earlier work (duda et al., 1990) suggested that the gene 29 protein could be involved in t4 tail length determination as a "template" or "tape-measure", similar to that proposed for the gene h protein in bacteriophage lambda. we have altered the length of a recombinant gene 29 by constructing deletions and duplications in different parts of the gene. each of these constructs was incorporated into the high-level expr ...19948122363
a gene cassette for adapting escherichia coli strains as hosts for att-int-mediated rearrangement and pl expression vectors.a cassette of genes from bacteriophage lambda, when carried on a derivative of bacteriophage mu, renders strains of escherichia coli (and in principle other mu-sensitive bacteria) capable of supporting lambda-based expression vectors, such as rearrangement vectors and pl vectors. the gene cassette contains a temperature-sensitive allele of the repressor gene, cits857, and a shortened leftward operon comprising, olpl, n, xis and int. transfection and lysogenization of this cassette into various h ...19948125284
the genomic structure of an insertional mutation in the dystonia musculorum locus.we have previously identified a line of transgenic mice, tg4, in which an hsp68-lacz hybrid gene has inserted into the dystonia musculorum (dt) locus on chromosome 1. we have confirmed the localization of the tg4 integration site to the proximal region of mouse chromosome 1 by interspecific backcross analysis. one end of the integration complex has been cloned and we have used single-copy probes from the flanking region to screen a mouse genomic library. several overlapping lambda phage clones h ...19948034309
exon amplification from complete libraries of genomic dna using a novel phage vector with automatic plasmid excision facility: application to the mouse neurofibromatosis-1 locus.the identification of transcription units in the vicinity of chromosomal lesions found in tumours is an essential step in the identification of new oncogenes. here, we describe a lambda phage vector system for genomic exon-trapping (lambda get), which dramatically simplifies the task of exon amplification from genomic dna. the vector accommodates about 6.5 to 19 kb of dna and allows inserts to be automatically subcloned as multi-copy plasmids containing splice donor and acceptor sites positioned ...19948036002
sequence of the vanb and ddl genes encoding d-alanine:d-lactate and d-alanine:d-alanine ligases in vancomycin-resistant enterococcus faecalis v583.a pair of degenerate oligodeoxyribonucleotides was used to amplify, by the polymerase chain reaction (pcr), dna fragments internal to genes encoding d-ala:d-ala ligase-related proteins of vancomycin-resistant (vmr) enterococcus faecalis v583. cloning and nucleotide sequencing of the pcr products indicated that fragments of two genes, designated vanb and ddl, were co-amplified. the vanb gene was previously shown to be present in enterococcus strains expressing vanb-type vmr [quintiliani jr. et al ...19948125347
synthesis and assembly of the f0 proton channel from f0 genes cloned into bacteriophage lambda and integrated into the escherichia coli chromosome.the promoter region and the first four genes of the escherichia coli proton-translocating atpase (unc) operon, uncibef, were cloned into bacteriophage lambda, enabling this region to be recombined into an unc-deleted e. coli chromosome at the lambda att site. the resultant e. coli strain, carrying single-copy f0 genes, was tested for synthesis and assembly of functional f0 proton channels. membranes isolated from this strain contained all three f0 subunits and were capable of binding purified f1 ...19948125942
the effects of nucleotide sequence changes on dna secondary structure formation in escherichia coli are consistent with cruciform extrusion in vivo.the construction in bacteriophage lambda of a set of long dna palindromes with paired changes in the central sequence is described. identical palindrome centers were previously used by others to test the s-type model for cruciform extrusion in vitro. long dna palindromes prevent the propagation of carrier phage lambda on a wild-type host, and the sbcc mutation is sufficient to almost fully alleviate this inviability. the plaque areas produced by the palindrome containing phages were compared on ...19948070650
partition of nonreplicating dna by the par system of bacteriophage p1.p1 plasmid encodes a cis-acting centromere analog, pars, and two par proteins that together stabilize plasmids by partitioning them to daughter bacteria. we infected immune bacteria with bacteriophage lambda into which pars had been inserted. the presence of p1 par proteins in the infected cells was found to delay the appearance of cells cured of the nonreplicating, extrachromosomal lambda-pars dna. this stabilization of lambda-pars, approximated in a computer simulation, demonstrates that activ ...19948132477
photoinactivation of bacteriophage lambda by kojic acid and fe(iii): role of oxygen radical intermediates in the reaction.kojic acid, a bacterial metabolite, intensively used in food and pharmaceutical industry has been reported to induce strand breaks in double stranded dna. this genotoxic action of kojic acid was tested directly by using bacteriophage inactivation. the inactivating activity is mediated through dna strand scissions by oxygen free radical intermediates. this was tested by quenching of the inactivation reaction in presence of radical scavengers. these results indicate the usefulness of a simple syst ...19948038723
function of a nontranscribed dna strand site in transcription elongation.a prolonged pause in transcription elongation at positions +16 and +17 of the phage lambda late gene operon has an important role in the modification of rna polymerase by the lambda gene q transcription antiterminator. mutations included in the transcription bubble of the paused transcription complex, particularly at +2 and +6, abolish pausing and the ability of q protein to modify rna polymerase. by transcribing heteroduplex templates made in vitro, we show that the sites identified by these mu ...19948044843
synergistic activation of transcription by bacteriophage lambda ci protein and e. coli camp receptor protein.two heterologous prokaryotic activators, the bacteriophage lambda ci protein (lambda ci) and the escherichia coli cyclic amp receptor protein (crp), were shown to activate transcription synergistically from an artificial promoter bearing binding sites for both proteins. the synergy depends on a functional activation (positive control) surface on each activator. these results imply that both proteins interact directly with rna polymerase and thus suggest a precise mechanism for transcriptional sy ...19948091212
site-specific targeting of psoralen photoadducts with a triple helix-forming oligonucleotide: characterization of psoralen monoadduct and crosslink formation.a polypurine tract in the supf gene of bacteriophage lambda (base pairs 167-176) was selected as the target for triple helix formation and targeted mutagenesis by an oligopurine (5'-aggaaggggg-3') containing a chemically linked psoralen derivative (4'-hydroxymethyl-4,5',8-trimethylpsoralen) at its 5' terminus (psoag10). the thymines at base pairs 166 and 167, a 5'apt site, were targeted for photomodification. exposure of the triple helical complex to long wavelength ultraviolet radiation led to ...19948052539
identification of two promoter regions in the rat b-50/gap-43 gene.to determine cis-acting elements controlling the rat b-50/gap-43 gene expression, the genomic dna encoding exon 1 and the 5' flanking sequence was isolated. sequence analysis of 1 kb 5' untranslated region (utr) revealed the presence of a (ga)-repeat and a (gt)-repeat. the size of the (ga)-repeat varied due to both an instability of phage lambda lambda dna in e. coli and genomic variation between rats. transcription initiation sites were mapped in 8-day-old rat brain poly(a)+ mrna. primer extens ...19948057779
single-site mutations in the c-terminal domain of bacteriophage lambda ci repressor alter cooperative interactions between dimers adjacently bound to or.wild-type ci repressor dimers bind with 2.5-3 kcal/mol of cooperative free energy to the tripartite right operator region (or) of bacteriophage lambda [johnson, a. d., et al. (1981) nature 294, 217-223; brenowitz, m., et al. (1986) methods enzymol. 130, 132-181]. quantitative modeling has suggested that cooperativity is required for maintenance of the lysogenic state and for the efficient switch from lysogenic to lytic growth [ackers, g. k., et al. (1982) proc. natl. acad. sci. u.s.a. 79, 1129-1 ...19948031776
structural organization of the human tyrosinase gene and sequence analysis and characterization of its promoter region.tyrosinase is the principal enzyme in the biosynthesis of melanin. the expression of tyrosinase is tissue-specific and appears to be regulated by various hormonal and environmental factors. elucidation of the genomic structure and molecular basis of control of tyrosinase gene expression will greatly enhance our understanding of the regulation of human pigmentation. to this end, we have isolated and performed restriction mapping of recombinant cosmid and lambda phage clones containing the human t ...19948176257
combined conformational search and finite-difference poisson-boltzmann approach for flexible docking. application to an operator mutation in the lambda repressor-operator complex.the n-terminal domain of the phage lambda repressor binds as a dimer to its palindromic dna operator sequence. in addition to a helix-turn-helix dna recognition motif, the first six amino acids of the phage lambda repressor form a flexible peptide segment which wraps around dna. site-directed mutagenesis studies have shown that amino acid replacements or partial removal of the arm structure, or changes in the dna sequence contacting the n-terminal arm, can lower the repressor-operator binding af ...19948176736
molecular genetic analysis of the nagh gene encoding a hyaluronidase of clostridium perfringens.a recombinant lambda phage was identified in a clostridium perfringens genomic library by means of its ability to hydrolyse the fluorescent substrate 4-methyl-umbelliferyl-beta-d-glucosaminide, isolated and shown to encode an endo-beta-n-acetylglucosaminidase. this enzyme, nagh, is also known as hyaluronidase, or mu toxin, a putative virulence factor which is likely to act on connective tissue during gas gangrene. nucleotide sequence analysis allowed the primary structure to be deduced and showe ...19948177218
generation of bacteriophage lambda lysogens by electroporation. 19948179876
[superproduction of bacillus intermedius 7p ribonuclease (binase) in escherichia coli].we have reported previously about the cloning of the binase gene in e. coli. in this work, using an original approach named "homolog gene recombination" method (hgr), vectors for binase expression in e. coli have been constructed. transcription of the binase gene have been directed through either tac-promoter or pr-promoter of bacteriophage lambda under the control of temperature-sensitive ci857 repressor. the last promoter gave the maximum yield of binase, up to 100 mg of protein per litre of h ...19948183278
generating bacteriophage lambda sublibraries enriched for rare clones. 19948185914
genetic analysis of alpha 2-adrenergic receptors and blood pressure using dahl salt-sensitive rats.to evaluate the role of alpha 2-adrenergic receptors in genetic hypertension by cosegregation analysis using dahl rats.19948064159
transcription of the halophage phi h repressor gene is abolished by transcription from an inversely oriented lytic promoter.the temperate phage phi h of the extremely halophilic archaebacterium halobacterium salinarium encodes a repressor, rep, which in the immune state represses the production of an early lytic transcript, denoted t4. rep acts at the transcriptional level by blocking the promoter for t4. the promoter for the rep gene itself is positioned back to back to the promoter for t4, in a manner analogous to that of the ci/cro genes in bacteriophage lambda. transcription of the rep gene does not occur when th ...19948187870
secondary structure and interaction of phage d108 ner repressor with a 61-base-pair operator: evidence for altered protein and dna structures in the complex.ner repressors of the transposable phages mu and d108 play a central role in regulating the expression of the early (transposase) operon and in ensuring that phage growth proceeds along a lytic pathway. the latter function is analogous to that performed by the cro protein of phage lambda. unlike lambda cro, however, the structural basis of operator recognition is not known for the ner repressors. in order to elucidate the structural features underlying operator recognition by ner repressors, we ...19948075070
the dcc gene: structural analysis and mutations in colorectal carcinomas.dcc is a candidate tumor-suppressor gene encoding a protein with sequence similarity to cell adhesion molecules such as n-cam. a set of overlapping yac clones that contains the entire dcc coding region was isolated. studies of this yac contig showed that the dcc gene spans approximately 1.4 mb. for elucidation of exon-intron structure, lambda phage clones containing all known coding sequences were isolated from a genomic library. these clones were used to demonstrate the existence of 29 dcc exon ...19948188295
the in vitro atpases of bacteriophage lambda terminase and its large subunit, gene product a. the relationship with their dna helicase and packaging activities.the bacteriophage lambda terminase is composed of two subunits, gpnu1 and gpa. in vitro, the holoenzyme is a site-specific endonuclease, helicase, atpase, and can package lambda dna into proheads. gpa possesses atpase and helicase activities which are similar to those of the holoenzyme. both terminase and gpa can hydrolyze a wide range of deoxyribo- and ribonucleoside triphosphates to inorganic phosphate and the corresponding diphosphate. nucleoside diphosphates are not substrates for either pro ...19948175794
isolation of region specific single-copy probes from human chromosome 1q23-->1q25.single-copy sequences of chromosome bands 1q23-->1q25 were enriched by subtractive hybridization of digoxigenin oligonucleotide-labeled dna from a somatic cell hybrid containing human chromosome 1 with dna from a somatic cell hybrid containing a deleted human chromosome 1, del(1)(q23q25). these sequences were purified with an immobilized anti-digoxigenin antibody, amplified by polymerase chain reaction (pcr) and cloned. the majority of clones contained single-copy sequences, thus allowing direct ...19948187551
ire-bubble pcr: a rapid method for efficient and representative amplification of human genomic dna sequences from complex sources.a significant issue in the analysis of any genomic dna segment is the generation of a unique set of short single-copy sequences that are representative of that region. in this report we describe a novel technique, ire-bubble pcr, which was designed to amplify the human dna content of somatic cell hybrids, yacs, cosmids, and lambda phage and result in greater complexity and representation than standard inter-ire pcr. here we demonstrate that ire-bubble pcr is species specific and that it results ...19948188293
amino acid substitutions in the -35 recognition motif of sigma 70 that result in defects in phage lambda repressor-stimulated transcription.the phage lambda repressor activates transcription of its own gene from the promoter prm. previous work has suggested that this activation involves a protein-protein interaction between dna-bound repressor and rna polymerase. to identify the subunit of rna polymerase that participates in this putative interaction, we searched for polymerase mutants that responded poorly to repressor. we report here the isolation of three sigma mutants that caused defects in repressor-stimulated, but not basal, t ...19948188599
Refresh
firstprev
...11121314151617181920...
nextlast
Displaying items 1901 - 2000 of 6653