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

• Published in: PLoS genetics 2008-05, Vol.4 (5), p.e1000066
• Main Authors: Spierer, Anne, Begeot, Flora, Spierer, Pierre, Delattre, Marion
• Format: Article
• Language: English
• Subjects: Animals; Animals, Genetically Modified; ATP-Binding Cassette Transporters - genetics; Chromatin; Chromosomes; Crosses, Genetic; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Dosage Compensation, Genetic; Drosophila melanogaster - genetics; Drosophila Proteins - genetics; Drosophila Proteins - metabolism; Eye Proteins - genetics; Female; Gene Expression; Genes, Insect; Genetics; Genetics and Genomics/Chromosome Biology; Genetics and Genomics/Epigenetics; Genetics and Genomics/Gene Expression; Genetics and Genomics/Gene Function; Genetics and Genomics/Nuclear Structure and Function; Heterochromatin - genetics; Heterochromatin - metabolism; Insects; Kinases; Male; Nuclear Proteins - genetics; Nuclear Proteins - metabolism; Proteins; Transcription Factors - genetics; Transcription Factors - metabolism; X Chromosome - genetics; X Chromosome - metabolism
• ISSN: 1553-7404; 1553-7390; 1553-7404
• DOI: 10.1371/journal.pgen.1000066

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.