Cold-induced alteration in the global structure of the male sex chromosome of In1BM2(reinverted) of Drosophila melanogaster is associated with increased acetylation of histone 4 at lysine 16.
In Drosophila melanogaster, dosage compensation occurs through hypertranscription of sex-linked genes in males. The hypertranscription involves acetylation of histone 4 at lysine 16 (H4K16) on amale X-chromosome, brought about by a histone acetyltransferase encoded by the dosage compensation gene, males absent on the first (mof). We report a phenomenon in the strain In(1)B(M2)(reinverted) of D. melanogaster where the global structure of the male X-chromosome can be altered at the third instar larval stage through a 4-h cold shock at 12+/-1 degrees C. We show that the cold shock results in a transient hyperacetylation of H4K16 and an increased expression of MOF. Control proteins H4 acetylated at lysine 5, and the dosage compensation gene msl-2, do not show any change in expression after cold shock. Cytology of the male X-chromosome at different time points during cold shock and recovery, suggests that the hyperacetylation of H4 at lysine 16 causes the X-chromosome to corkscrew into itself, thereby achieving the cold-induced change in the higher order structure of the male polytene X-chromosome. Our studies suggest a role for H4K16 in maintaining the structure of the male X-chromosome in Drosophila.
Kulkarni-Shukla
S
S
Department of Biotechnology, Sinhgad College of Engineering, Vadgaon Budruk, Pune 411 041, India.
Barge
A P
AP
Vartak
R S
RS
Kar
Anita
A
D000107:Acetylation; D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism; D003080:Cold Temperature; D004331:Drosophila melanogaster / Q000378:metabolism*; D005260:Female; D006657:Histones / Q000378:metabolism*; D015151:Immunoblotting; D007814:Larva / Q000378:metabolism; D008239:Lysine / Q000378:metabolism*; D008297:Male; D014960:X Chromosome / Q000378:metabolism*
D006657:Histones; D008239:Lysine