| incn plasmid pkm101 and inci1 plasmid colib-p9 encode homologous antirestriction proteins in their leading regions. | the incn plasmid pkm101 (a derivative of r46), like the inci1 plasmid colib-p9, carries a gene (arda, for alleviation of restriction of dna) encoding an antirestriction function. arda was located about 4 kb from the origin of transfer, in the region transferred early during bacterial conjugation. the nucleotide sequence of arda was determined, and an appropriate polypeptide with the predicted molecular weight of about 19,500 was identified in maxicells of escherichia coli. comparison of the dedu ... | 1992 | 1321121 |
| structural and functional features of cis-acting sequences in the basic replicon of plasmid colib-p9. | we have structurally and functionally analyzed the cis-elements essential for colib-p9 plasmid dna replication. the putative oriv region encompassed a region of 172 base pairs (bp) located 152 bp downstream of the repz gene. a typical dnaa box found in this region proved nonessential for the dna replication of colib-p9. the ssi signal of colib-p9 is a homologue of the g-sites of r1 and r100 plasmids. deletion of the g-site led to 1.5-fold reduction of the copy number, suggesting that although th ... | 1992 | 1614857 |
| transfer of tra proteins into the recipient cell during bacterial conjugation mediated by plasmid colib-p9. | selective transfer of the two products of the colib primase gene, sog, from donor to recipient cell during conjugation was demonstrated by two independent methods. the transfer of these tra proteins was unidirectional and dependent on dna transfer. the sog polypeptides were localized to the cytoplasm of the donor cell, but they appeared to interact with other tra gene products located in the inner membrane. after cell mating, the transferred polypeptides were found to be in the cytoplasm of the ... | 1989 | 2656642 |
| [organization of the genes responsible for colicin ib synthesis and immunity to it in plasmid colib-p9]. | to study the localization and expression of the colib-p9 plasmid genes responsible for colicin ib synthesis and immunity to it, we isolated a series of tn5 insertion mutants of recombinant plasmid piv41 containing the colicin ib gene in ecori fragment of colib-p9 (2.7 kb) and the deletion plasmid carrying only a part of the colicin gene. the direction of colicin ib gene transcription was determined by the analysis of the polypeptides synthesized in minicells carrying the mutant plasmids. the piv ... | 1985 | 2989085 |
| role of sog polypeptides specified by plasmid colib-p9 and their transfer between conjugating bacteria. | the sog gene of the conjugative plasmid colib-p9 specifies two sequence-related polypeptides with the n-terminal third of the larger product having dna primase activity. to resolve the function of the c-terminal portion of the polypeptides, we constructed a colib mutant containing a tn5 insertion in the 3' region of sog. the mutation truncated sog gene products without inactivating dna primase and rendered the plasmid defective in conjugation. tests for the presence of conjugative pili, for comp ... | 1986 | 3024972 |
| direction of conjugative transfer of inci1 plasmid colib-p9. | the origin-of-transfer region of colib-p9 was inserted into a lambda prophage to give a bacterial chromosome mobilizable by the parental conjugative plasmid. the polarity of mobilization of chromosomal genes indicated that colib-p9 transfer is unidirectional, such that the transfer genes adjacent to orit enter the recipient cell last. | 1988 | 3049555 |
| [molecular cloning of plasmid colib-p9 genes responsible for its mutator function]. | the localization of plasmid colib-p9 muc genes mediating the plasmids protective and mutagenesis-increasing activity has been determined. the increase of muc genes dose by cloning them within the multicopy vector has been shown to repress the mutator function of the plasmid. no essential homology has been revealed between colib-p9 muc gene nucleotide sequences, pkm101 muc genes with a similar function, and umudc chromosome genes. it has been shown that the synthesis of 38 kd protein is essential ... | 1988 | 3062392 |
| role and specificity of plasmid rp4-encoded dna primase in bacterial conjugation. | the role of the dna primase of incp plasmids was examined with a derivative of rp4 containing tn7 in the primase gene (pri). the mutant was defective in mediating bacterial conjugation, with the deficiency varying according to the bacterial strains used as donors and recipients. complementation tests involving recombinant plasmids carrying cloned fragments of rp4 indicated that the primase acts to promote some event in the recipient cell after dna transfer and that this requirement can be satisf ... | 1986 | 3522540 |
| [reactivation of ultraviolet-irradiated phage lambda and recombination in escherichia coli k-12 cells containing plasmid colib-p9]. | it was shown that the presence of colicinogenis plasmid colib-p9 increased the survival of uv-irradiated bacteriophage lambda ci857 in non-irradiated cells of escherichia coli k-12. the effect of this plasmid was retained in the pola and recb mutants, being sharply reduced in the uvra and recb recc sbcb recf mutants. this effect strongly depended on reca+ and lexa+ genotype. the w-reactivation efficiency was slightly higher in the cells containing colib-p9 than in those lacking the plasmid. no s ... | 1983 | 6219916 |
| effect of the plasmid colib-p9 on cellular processes related to dna repair. | the plasmid colib-p9 introduced into escherichia coli k12 umuc mutant cells suppresses the deficiencies in mutagenesis and repair of mutants after uv-irradiation. these data suggest that colib-p9 encodes a product with a function similar to that of the chromosomal gene umuc. tn5 insertion mutants of colib-p9 were isolated with an altered ability to restore uv-mutagenesis in the umuc mutant. the same plasmid mutations were shown to eliminate the effects of colib-p9 on uv-mutagenesis, survival aft ... | 1984 | 6323923 |
| [action of plasmid colib-p9 on the survival after ultraviolet irradiation and on the mutagenesis of the imic, uvm, recl, uvre and tif1 sfia lexa spr mutants of escherichia coli k-12 cells]. | to clarify the mechanisms whereby the colib-p9 plasmid affects dna repair processes, its effect was studied in mutant escherichia coli k-12 cells with altered mutagenesis and dna repair. the plasmid was shown to protect umuc, uvm, recl and uvre mutants after uv irradiation. the frequency of uv-induced his+ revertants increased in the presence of the plasmid in umuc, uvm and recl mutant cells. the colib-p9 plasmid completely restored the uv mutability and survival of umuc mutants. these results s ... | 1983 | 6354842 |
| detection of primase specified by incb plasmid r864a. | plasmid r864a (incb) contains nucleotide sequences homologous with the sog primase determinant of inci alpha plasmid colib-p9. extracts of escherichia coli carrying a mutant r864a derepressed for transfer functions showed enhanced primase activity, and contained a large polypeptide identical in size (apparent mr = 220,000) to the inci alpha sog gene product. | 1982 | 6752124 |
| the influence of colicinogenic plasmids colib-p9, colia-ca53 and colv-k30 on the repair, mutagenesis and induction of colicin e1 synthesis. | the presence of colicinogenic plasmids colib-p9 and colia-ca53 in e. coli k-12 cells, wild-type with respect to repair, enhanced the survival of cells after uv irradiation and increased the frequency of uv-induced arge3 and his-4 reversions, while the presence of colv-k30 negatively affected repair and mutagenesis. the plasmid colib-p9 showed a uv-protective effect in e. coli cells carrying mutations in genes uvra, uvrb, uvrc, pola, recb, recf, though in none of the mutants did cell survival rea ... | 1981 | 7012544 |
| evidence for two genetically distinct dna primase activities specified by plasmids of the b and i incompatibility groups. | plasmid colib-p9 of the i alpha incompatibility group is known to encode a dna primase that acts in the conjugal transfer of the plasmid and can substitute for mutant dnag gene product in vegetative replication of the escherichia coli chromosome. the relevant genetic determinant (sog) has previously been cloned into a small multicopy vector plasmid. prototype incb plasmid r16 also suppresses host dnag mutations. the equivalent gene(s) (pri) of r16 was cloned into plasmid pbr325 and shown by filt ... | 1982 | 7045070 |
| a transcription terminator signal necessary for plasmid colib-p9 replication. | replication of the inci alpha plasmid colib-p9 requires the repz gene, which encodes an essential, unstable initiator protein termed repz. although many functional features of the colib-p9 replicon resemble those of structurally unrelated incfii plasmids r1 and nr1, the role of transcription of repz towards the replication origin is poorly understood. using a series of deletion and substitution mutants of the colib-p9 replicon, we found that repz prefers to act in cis and that a spacer sequence ... | 1995 | 7494478 |
| distribution of the arda family of antirestriction genes on conjugative plasmids. | the arda gene of i1 plasmid colib-p9 was previously shown to alleviate dna restriction by type i enzymes and to promote conjugative transmission of the unmodified plasmid to a restricting host. to clarify the ecological role of arda, its distribution was determined on plasmids from 23 incompatibility groups using hybridization to the coding sequence as an assay. hybridizing sequences, shown by nucleotide sequencing to have at least 60% identity with arda, were detected on plasmids belonging to t ... | 1995 | 7496527 |
| expression of leading region genes on inci1 plasmid colib-p9: genetic evidence for single-stranded dna transcription. | the leading region of a plasmid is the first sector to enter the recipient cell in bacterial conjugation. this sector of inci1 plasmid colib-p9 includes genes that are transcribed in a transient pulse early in the conjugatively infected cell to promote establishment of the immigrant plasmid. evidence is presented that the burst of gene expression is regulated by a process which is independent of a repressor but dependent on the orientation of the genes on the unique plasmid strand transferred in ... | 1999 | 10537187 |
| [mutational analysis of the conserved motif of the arda anti-restriction protein encoded by self-transmissible inci plasmid colib-p9]. | a study was made of the functional role of the arda antirestriction motif (130-lladvpetvalyfd-143) conserved among all known ard (alleviation of restriction of dna) proteins, which are encoded by self-transmissible plasmids and specifically inhibit type i restriction-modification systems. conserved residues of the motif were individually changed, and the resulting mutants tested for in vivo activity. hydrophobic l130, l131, and v138 were substituted with negatively charged e; negatively charged ... | 2002 | 12500545 |
| the activity of a single-stranded promoter of plasmid colib-p9 depends on its secondary structure. | the leading region of the conjugal bacterial plasmid colib-p9 contains three dispersed repeats of a 328 bp sequence homologous to frpo, a sequence from plasmid f that acts as a promoter in single-stranded dna. one of these sequences, ssi3, inactive in the double-stranded form, promoted in vitro transcription exclusively from the single strand that is transferred during conjugation. promoter activity was dependent on the presence of rna polymerase holoenzyme containing sigma 70. transcription ini ... | 2004 | 15228523 |
| comparative analysis of anti-restriction activities of arda (colib-p9) and ocr (t7) proteins. | anti-restriction proteins arda and ocr are specific inhibitors of type i restriction-modification enzymes. the inci1 transmissible plasmid colib-p9 arda and bacteriophage t7 0.3(ocr) genes were cloned in puc18 vector. both arda (colib-p9) and ocr (t7) proteins inhibit both restriction and modification activities of the type i restriction-modification enzyme (ecoki) in escherichia coli k12 cells. colib-p9 arda, t7 0.3(ocr), and the photorhabdus luminescens luxcdabe genes were cloned in pz-series ... | 2008 | 18774937 |
| complete genome sequence of the incompatibility group i1 plasmid r64. | a streptomycin and tetracycline resistance plasmid r64 isolated from salmonella enterica serovar typhimurium belongs to the incompatibility group i1 (inci1). the dna sequence of the r64 conjugative transfer region was described previously (komano et al., 2000). here, we report the complete genome sequence of r64. in the circular double-stranded r64 genome with 120,826bp, 126 complete orfs are predicted. in addition, 2 and 6 different kinds of proteins are produced by translational reinitiation a ... | 2010 | 20594994 |
| structural analysis of late intermediate complex formed between plasmid colib-p9 inc rna and its target rna. how does a single antisense rna repress translation of two genes at different rates? | the antisense inc rna encoded by the incialpha colib-p9 plasmid replicon controls the translation of repz encoding the replication initiator and its leader peptide repy at different rates with different mechanisms. the initial loop-loop base pairing between inc rna and the target in the repz mrna leader inhibits formation of a pseudoknot required for repz translation. a subsequent base pairing at the 5' leader of inc rna blocks repy translation. to delineate the molecular basis for the different ... | 2000 | 10625672 |
| the plasmid colib-p9 antisense inc rna controls expression of the repz replication protein and its positive regulator repy with different mechanisms. | the autonomous replication region of plasmid colib-p9 contains repz encoding the repz replication protein, and inc and repy as the negative and positive regulators of repz translation, respectively. inc encodes the antisense inc rna, and repy is a short open reading frame upstream of repz. translation of repy enables repz translation by inducing formation of a pseudoknot containing stem-loop i, which base pairs with the sequence preceding the repz start codon. inc rna inhibits both repy translat ... | 1999 | 10364239 |
| copy number control of incialpha plasmid colib-p9 by competition between pseudoknot formation and antisense rna binding at a specific rna site. | replication of a low-copy-number incialpha plasmid colib-p9 depends on expression of the repz gene encoding the replication initiator protein. repz expression is negatively controlled by the small antisense inc rna, and requires formation of a pseudoknot in the repz mrna consisting of stem-loop i, the inc rna target, and a downstream sequence complementary to the loop i. the loop i sequence comprises 5'-ruuggcg-3', conserved in many prokaryotic antisense systems, and was proposed to be the impor ... | 1998 | 9724656 |
| structural basis for binding of the plasmid colib-p9 antisense inc rna to its target rna with the 5'-ruuggcg-3' motif in the loop sequence. | the sequence 5'-ruuggcg-3' is conserved within the loop regions of antisense rnas or their targets involved in replication of various prokaryotic plasmids. in incialpha plasmid colib-p9, the partially base paired 21-nucleotide loop of a stem-loop called structure i within repz mrna contains this hexanucleotide sequence, and comprises the target site for the antisense inc rna. in this report, we find that the base pairing interaction at the 5'-rggc-3' sequence in the hexanucleotide motif is impor ... | 1998 | 9565607 |
| an rna pseudoknot as the molecular switch for translation of the repz gene encoding the replication initiator of incialpha plasmid colib-p9. | translation initiation of the repz gene encoding the replication initiator of plasmid colib-p9 is not only negatively regulated by the action of the antisense inc rna encoded in the leader region, but is also coupled to the translation and termination of a transcribed leader sequence, repy, a positive regulatory element for repz gene expression. this translational coupling depends on base pairing between two complementary sequences, 5'-rggcg-3' and 5'-rcgcc-3', which are located upstream of and ... | 1998 | 9565606 |
| the btub group col plasmids and homology between the colicins they encode. | colicins a, e1, e2, e3, e4, e5, e6, and e7 exhibited reduced activity against btub mutants of escherichia coli k-12 and also against wild-type cells in the presence of vitamin b12. plasmids encoding representatives of these colicins were specifically immune to high levels of the homologous colicin. col(+) cells grown in media containing mitomycin c accumulated large amounts of colicin polypeptide. cole2(+), cole3(+), cole4(+), cole5(+), and cole6(+) cultures also synthesized large amounts of sec ... | 1982 | 6281233 |
| organization and regulation of the conjugation genes of inci1 plasmid colib-p9. | the inci1 plasmid colib-p9 is among a group of related plasmids that encode the i1 type of conjugation system. the i1 system is known to include two morphologically distinct types of pilus, a dna primase gene (sog) and an exclusion determinant (exc). transposon mutagenesis and analysis of cloned fragments of colib were used to identify the location of these determinants with respect to an ecori restriction map. also identified were the location of the origin of transfer (orit) and a gene determi ... | 1987 | 2832863 |
| the ssb gene of plasmid colib-p9. | the inci1 plasmid colib-p9 was found to carry a single-stranded dna-binding (ssb) protein gene (ssb) that maps about 11 kilobase pairs from the origin of transfer in the region transferred early during bacterial conjugation. the cloned gene was able to suppress the uv and temperature sensitivity of an ssb-1 strain of escherichia coli k-12. the nucleotide sequence of the colib ssb gene was determined, giving a predicted molecular weight of 19,110 for the ssb protein. sequence data show that colib ... | 1989 | 2651402 |
| an induced mrna secondary structure enhances repz translation in plasmid colib-p9. | translation of the repz gene encoding a dna replication initiation protein of plasmid colib-p9 depends on not only the translation of a transcribed leader sequence (repy) but also the specific intergenic base pairing within repz mrna between two short complementary sequences located in the repy and inc gene regions. in addition, repz translation can be negatively regulated by inc rna, the product of the inc gene and a countertranscript to repz mrna. here we present evidence indicating that a sta ... | 1991 | 1722206 |
| positive and negative regulations of plasmid colib-p9 repz gene expression at the translational level. | expression of the repz gene involved in dna replication of the colib-p9 plasmid depends on translation of a transcribed repz leader sequence (repy) and is negatively regulated by inc rna, the product of the inc gene and a countertranscript to repz mrna. to further understand the regulatory loop of repz expression, we isolated and characterized replication-defective colib-p9 mutants that affected the level of repz expression. here we report that mutations occurring in two complementary sequences, ... | 1991 | 1704893 |
| posttranscriptional control of plasmid colib-p9 repz gene expression by a small rna. | the replication frequency of plasmid colib-p9 depends on the level of repz gene expression, which is negatively regulated by the action of the inc gene (c. hama, t. takizawa, h. moriwaki, y. urasaki, and k. mizobuchi, j. bacteriol. 172:1983-1991, 1990). to further understand the mechanism of this regulation, we analyzed transcripts of the colib-p9 replication control region. four rna species, designated rnai to rnaiv, were observed in plasmid pch11, which contained the whole inc gene region and ... | 1990 | 1690705 |
| organization of the replication control region of plasmid colib-p9. | we identified a 1,845-base-pair sequence that contains essential information for the autonomous replication and regulation of the 93-kilobase-pair inci alpha group colib-p9 plasmid. biochemical and genetic analyses revealed that this sequence specifies at least two structural genes, designated repz and inc. the repz gene encodes a protein with a molecular weight of 39,000, which probably functions as an initiator for the colib-p9 replicon. the inc gene that phenotypically governs the incompatibi ... | 1990 | 1690704 |
| nucleotide sequence of the gene (ard) encoding the antirestriction protein of plasmid colib-p9. | the inci1 plasmid colib-p9 was found to encode an antirestriction function. the relevant gene, ard (alleviation of restriction of dna), maps about 5 kb from the origin of transfer, in the region transferred early during bacterial conjugation. ard inhibits both restriction and modification by each of the four type i systems of escherichia coli tested, but it had no effect on restriction by either ecori, a type ii system, or ecop1, a type iii system. the nucleotide sequence of the colib ard gene w ... | 1991 | 1653225 |
| plasmid-encoded antirestriction protein arda can discriminate between type i methyltransferase and complete restriction-modification system. | many promiscuous plasmids encode the antirestriction proteins arda (alleviation of restriction of dna) that specifically affect the restriction activity of heterooligomeric type i restriction-modification (r-m) systems in escherichia coli cells. in addition, a lot of the putative arda genes encoded by plasmids and bacterial chromosomes are found as a result of sequencing of complete genomic sequences, suggesting that arda proteins and type i r-m systems that seem to be widespread among bacteria ... | 2007 | 17069852 |