SU(VAR)3-7 links heterochromatin and dosage compensation in Drosophila

PLoS Genet. 2008 May 2;4(5):e1000066. doi: 10.1371/journal.pgen.1000066.

Abstract

In Drosophila, dosage compensation augments X chromosome-linked transcription in males relative to females. This process is achieved by the Dosage Compensation Complex (DCC), which associates specifically with the male X chromosome. We previously found that the morphology of this chromosome is sensitive to the amounts of the heterochromatin-associated protein SU(VAR)3-7. In this study, we examine the impact of change in levels of SU(VAR)3-7 on dosage compensation. We first demonstrate that the DCC makes the X chromosome a preferential target for heterochromatic markers. In addition, reduced or increased amounts of SU(VAR)3-7 result in redistribution of the DCC proteins MSL1 and MSL2, and of Histone 4 acetylation of lysine 16, indicating that a wild-type dose of SU(VAR)3-7 is required for X-restricted DCC targeting. SU(VAR)3-7 is also involved in the dosage compensated expression of the X-linked white gene. Finally, we show that absence of maternally provided SU(VAR)3-7 renders dosage compensation toxic in males, and that global amounts of heterochromatin affect viability of ectopic MSL2-expressing females. Taken together, these results bring to light a link between heterochromatin and dosage compensation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATP-Binding Cassette Transporters / genetics
  • Animals
  • Animals, Genetically Modified
  • Crosses, Genetic
  • DNA-Binding Proteins / genetics*
  • DNA-Binding Proteins / metabolism*
  • Dosage Compensation, Genetic*
  • Drosophila Proteins / genetics*
  • Drosophila Proteins / metabolism*
  • Drosophila melanogaster / genetics*
  • Eye Proteins / genetics
  • Female
  • Gene Expression
  • Genes, Insect
  • Heterochromatin / genetics*
  • Heterochromatin / metabolism*
  • Male
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism
  • Transcription Factors / genetics
  • Transcription Factors / metabolism
  • X Chromosome / genetics
  • X Chromosome / metabolism

Substances

  • ATP-Binding Cassette Transporters
  • DNA-Binding Proteins
  • Drosophila Proteins
  • Eye Proteins
  • Heterochromatin
  • Nuclear Proteins
  • Su(var)3-7 protein, Drosophila
  • Transcription Factors
  • msl-1 protein, Drosophila
  • msl-2 protein, Drosophila
  • w protein, Drosophila