Isolation and analysis of sequences showing sex-specific cytosine methylation in the mealybug Planococcus lilacinus

Mohan, Naga K and Chandra, Sharat H (2005) Isolation and analysis of sequences showing sex-specific cytosine methylation in the mealybug Planococcus lilacinus. In: Mol Gen Genomics, 274 (6). pp. 557-568.

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Abstract

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 similar to 2.5 times more often than those showing female-specific methylation. In order to directly isolate sequences showing sex-specific CpG methylation, we employed methylation-specific arbitrarily primed (MS-AP) polymerase chain reaction (PCR) and identified 72 sex-specific products, of which 51 were from males and 21 from females. Amplification of bisulfite-modified DNA and subsequent Southern hybridization showed that in 33 out of these 72 sex-specific products, there was differential methylation of homologous sequences; i.e., both methylated and unmethylated copies of the same sequence occurred in one sex whereas only unmethylated copies were present in the opposite sex. Sequencing of bisulfite-modified DNA showed an interspersion of CpG and non-CpG methylation among the sex-specifically methylated sequences. Sequences showing male-specific CpG methylation are organized as transcriptionally silent chromatin in males but not in females, whereas those showing female-specific CpG methylation are organized as transcriptionally silent chromatin in females but not in males. The sequences identified in this study that show differential methylation in males, but are unmethylated in females, may prove useful in the study of imprinting in the mealybug system.

Item Type:	Journal Article
Publication:	Mol Gen Genomics
Publisher:	Springer
Additional Information:	Copyright of this article belongs to Springer.
Keywords:	Insitu Nick Translation; Inactive X-Chromosomes; Dosage Paternal Irradiation;Dna Methylation; Drosophila-Melanogaster;Cpg Island;Citri;5-Methylcytosine;System;Genome
Department/Centre:	Division of Biological Sciences > Microbiology & Cell Biology
Date Deposited:	27 Aug 2009 05:20
Last Modified:	19 Sep 2010 04:55
URI:	http://eprints.iisc.ac.in/id/eprint/17199

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