SU(VAR)3-7 links heterochromatin and dosage compensation in Drosophila.
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.
Spierer
Anne
A
NCCR Frontiers in Genetics, Department of Zoology and Animal Biology, University of Geneva, Geneva, Switzerland.
Begeot
Flora
F
Spierer
Pierre
P
Delattre
Marion
M
D018528:ATP-Binding Cassette Transporters / Q000235:genetics; D000818:Animals; D030801:Animals, Genetically Modified; D003433:Crosses, Genetic; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D004303:Dosage Compensation, Genetic; D029721:Drosophila Proteins / Q000235:genetics* / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000235:genetics*; D005136:Eye Proteins / Q000235:genetics; D005260:Female; D015870:Gene Expression; D017344:Genes, Insect; D006570:Heterochromatin / Q000235:genetics* / Q000378:metabolism*; D008297:Male; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014960:X Chromosome / Q000235:genetics / Q000378:metabolism
D018528:ATP-Binding Cassette Transporters; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D005136:Eye Proteins; D006570:Heterochromatin; D009687:Nuclear Proteins; C449619:Su(var)3-7 protein, Drosophila; D014157:Transcription Factors; C082132:msl-1 protein, Drosophila; C094166:msl-2 protein, Drosophila; C059254:w protein, Drosophila