| detection of a cpa methylase in an insect system: characterization and substrate specificity. | a cytosine-specific dna methyltransferase (ec 2.1.1.37) has been purified to near homogeneity from a mealybug (planococcus lilacinus). the enzyme can methylate cytosine residues in cpg sequences as well as cpa sequences. the apparent molecular weight of the enzyme was estimated as 135,000 daltons by fplc. the enzyme exhibits a processive mode of action and a salt dependence similar to mammalian methylases. mealybug methylase exhibits a preference for denatured dna substrates. | 1992 | 1374836 |
| a male-specific nuclease-resistant chromatin fraction in the mealybug planococcus lilacinus. | in mealybugs, chromatin condensation is related to both genomic imprinting and sex determination. the paternal chromosomal complement is condensed and genetically inactive in sons but not in daughters. during a study of chromatin organization in planococcus lilacinus, digestion with micrococcal nuclease showed that 3% to 5% of the male genome is resistant to the enzyme. this nuclease resistant chromatin (nrc) apparently has a nucleosomal organization. southern hybridization of genomic dna sugges ... | 1996 | 8575251 |
| developmental analysis of a female-specific 16s rrna gene from mycetome-associated endosymbionts of a mealybug, planococcus lilacinus. | a clone showing female-specific expression was identified from an embryonic cdna library of a mealybug, planococcus lilacinus. in southern blots this clone (p7) showed hybridization to genomic dna of females, but not to that of males. however, p7 showed no hybridization to nuclei of either sex, raising the possibility that it was extrachromosomal in origin. in sectioned adult females p7 hybridized to an abdominal organ called the mycetome. the mycetome is formed by mycetocytes, which are polyplo ... | 1996 | 9035384 |
| sex-specific organisation of middle repetitive dna sequences in the mealybug planococcus lilacinus. | differential organisation of homologous chromosomes is related to both sex determination and genomic imprinting in coccid insects, the mealybugs. we report here the identification of two middle repetitive sequences that are differentially organised between the two sexes and also within the same diploid nucleus. these two sequences form a part of the male-specific nuclease-resistant chromatin (nrc) fraction of a mealybug planococcus lilacinus. to understand the phenomenon of differential organisa ... | 1999 | 10471745 |
| characterization of the genome of the mealybug planococcus lilacinus, a model organism for studying whole-chromosome imprinting and inactivation. | the co-occurrence of three chromosome-wide phenomena--imprinting, facultative heterochromatization and diffuse centromere--in the mealybug planococcus lilacinus makes investigation of the genomics of this species an attractive prospect. in order to estimate the complexity of the genome of this species, 300 random stretches of its dna, constituting approximately 0.1% of the genome, were sequenced. coding sequences appear to constitute approximately 53.5%, repeat sequences approximately 44.5% and ... | 2002 | 12073549 |
| isolation and analysis of sequences showing sex-specific cytosine methylation in the mealybug planococcus lilacinus. | genomic libraries of planococcus lilacinus, a mealybug in which paternal chromosomes are facultatively heterochromatic and inactive in sons but not in daughters, were probed with subtraction probes in order to estimate the number of sequences displaying sex-specific cytosine methylation in cpg dinucleotides. sequences showing male-specific methylation were found to occur approximately 2.5 times more often than those showing female-specific methylation. in order to directly isolate sequences show ... | 2005 | 16283386 |
| comparison of mealybug (planococcus lilacinus) and fruit fly genomes: isolation and analysis of conserved sequences and their utility in studying synteny in the mealybug. | by using ligation-mediated pcr products from mealybug dna as tester and biotinylated fly dna as driver, we recovered a fraction of the tester that remains hybridized to driver following high-stringency washing conditions. this fraction is expected to contain mealybug sequences conserved in the fly (mcf). reciprocal experiments enabled the isolation of fly sequences conserved in the mealybug (fcm). coding sequences among mcf show amino acid identities >40% with fly proteins, allowing a reliable i ... | 2008 | 18253039 |
| characterization of ttagg telomeric repeats, their interstitial occurrence and constitutively active telomerase in the mealybug planococcus lilacinus (homoptera; coccoidea). | we confirmed the occurrence of the insect ttagg telomeric repeats in the mealybug planococcus lilacinus, a radiation-resistant coccid, by single primer polymerase chain reaction (pcr) and southern hybridization. analysis of bal31 nuclease-digested dna by southern hybridization and chromosomes by fish suggests that these repeats occur mainly at the ends of the chromosomes. however, sequence analysis of the pcr products of ttagg-associated sequences from genomic dna showed their interstitial occur ... | 2010 | 21088846 |
| an analysis of histone modifications in relation to sex-specific chromatin organization in the mealybug maconellicoccus hirsutus. | the male-specific heterochromatization of the paternal genome, observed in coccids, is an example of both genomic imprinting and differential regulation of homologous chromosomes. we observed a highly nuclease-resistant chromatin (nrc) organization of a part of the paternal genome in males of maconellicoccus hirsutus as reported earlier in planococcus lilacinus. the nuclease resistance of nrc is correlated with nuclear matrix association and is lost when nrc is dissociated from the matrix. we ca ... | 2010 | 20616523 |