X-chromosome-wide profiling of MSL-1 distribution and dosage compensation in Drosophila

Genes Dev. 2006 Apr 1;20(7):871-83. doi: 10.1101/gad.377506. Epub 2006 Mar 17.

Abstract

In Drosophila, dosage compensation is achieved by a twofold up-regulation of the male X-linked genes and requires the association of the male-specific lethal complex (MSL) on the X chromosome. How the MSL complex is targeted to X-linked genes and whether its recruitment at a local level is necessary and sufficient to ensure dosage compensation remain poorly understood. Here we report the MSL-1-binding profile along the male X chromosome in embryos and male salivary glands isolated from third instar larvae using chromatin immunoprecipitation (ChIP) coupled with DNA microarray (ChIP-chip). This analysis has revealed that majority of the MSL-1 targets are primarily expressed during early embryogenesis and many target genes possess DNA replication element factor (DREF)-binding sites in their promoters. In addition, we show that MSL-1 distribution remains stable across development and that binding of MSL-1 on X-chromosomal genes does not correlate with transcription in male salivary glands. These results show that transcription per se on the X chromosome cannot be the sole signal for MSL-1 recruitment. Furthermore, genome-wide analysis of the dosage-compensated status of X-linked genes in male and female shows that most of the X chromosome remains compensated without direct MSL-1 binding near the gene. Our results, therefore, provide a comprehensive overview of MSL-1 binding and dosage-compensated status of X-linked genes and suggest a more global effect of MSL complex on X-chromosome regulation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Base Sequence
  • Binding Sites / genetics
  • Chromatin Immunoprecipitation
  • DNA / genetics
  • DNA / metabolism
  • Dosage Compensation, Genetic
  • Drosophila / embryology
  • Drosophila / genetics*
  • Drosophila / growth & development
  • Drosophila / metabolism*
  • Drosophila Proteins / genetics
  • Drosophila Proteins / metabolism*
  • Gene Expression Profiling
  • Genes, Insect
  • Larva / metabolism
  • Male
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism*
  • Oligonucleotide Array Sequence Analysis
  • Promoter Regions, Genetic
  • Protein Binding
  • Salivary Glands / metabolism
  • Sex Chromosomes / genetics*
  • Sex Chromosomes / metabolism*
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*
  • Transcriptional Activation

Substances

  • Dref protein, Drosophila
  • Drosophila Proteins
  • Nuclear Proteins
  • Transcription Factors
  • msl-1 protein, Drosophila
  • msl-3 protein, Drosophila
  • DNA