Comparison of dot chromosome sequences from D. melanogaster and D. virilisreveals an enrichment of DNA transposon sequences in heterochromatic domains

Elizabeth E Slawson ,James Dee,Fatih Ozsolak,Rachel B Shevchek,Jeremy Buhler,Elmer Kellmann,Jenny Myoung,Wilson Leung,Charles P Craig ,C Shaffer ,Colin D Malone ,James W Bogenpohl ,Seth M Bloom ,Elaine R Mardis ,Mary Lou Pardue ,Andrew Nett ,Emiko Morimoto ,Mindy Tittiger ,A Zeug ,Sarah C R Elgin

doi:10.1186/gb-2006-7-2-r15

Elizabeth E Slawson , James Dee + Show 18 more

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https://doi.org/10.1186/gb-2006-7-2-r15

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Abstract

Sequencing and analysis of fosmid hybridization to the dot chromosomes of Drosophila virilis and D. melanogaster suggest that repetitive elements and density are important in determining higher-order chromatin packaging.

Highlights

Chromosome four of Drosophila melanogaster, known as the dot chromosome, is largely heterochromatic, as shown by immunofluorescent staining with antibodies to heterochromatin protein 1 (HP1) and histone H3K9me
Immunofluorescent staining indicates that the D. virilis dot chromosome is largely euchromatic, in contrast to the heterochromatic D. melanogaster dot chromosome The dot chromosome of D. melanogaster is largely heterochromatic, with some interspersed domains of euchromatin [24]
In D. melanogaster, staining with an antibody against histone H3 methylated at lysine 9 coincides with the HP1 staining, at a level slightly less than seen in the pericentric heterochromatin [21] (Figure 1a)

Summary

Introduction

Chromosome four of Drosophila melanogaster, known as the dot chromosome, is largely heterochromatic, as shown by immunofluorescent staining with antibodies to heterochromatin protein 1 (HP1) and histone H3K9me. The absence of HP1 and H3K9me from the dot chromosome in D. virilis suggests that this region is euchromatic. Heterochromatic regions of the genome have very low rates of meiotic recombination and generally replicate late in S phase. These regions are rich in repetitive sequences, including remnants of transposable elements and retroviruses, as well as simple repeats (satellite DNA). The less densely packaged euchromatin contains most of the actively transcribed genes. In contrast to this general picture of repeat distribution, Pardue et al [5] have found by in situ hybridization that the frequency of (dC-dA)·(dG-dT) dinucleotide repeats is higher in euchromatin than in heterochromatin

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