| Modification Notes |
Control of chromosome structure plays a role in the regulation of gene expression, recombination, DNA repair, and chromosome stability. Drosophila SIR2, a NAD(+)-dependent histone deacetylase, influences euchromatic repression and heterochromatic silencing at telomeres, rDNA, and mating-type loci mediated by the Polycomb group of proteins and by physically associating with a complex containing the E(Z) histone methyltransferase. Deacetylation by SIR2 causes rearrangement of histones into a transcriptionally repressive chromatin structure. SIR2 has also been shown to be directly involved in the calorie-restriction life-span-extending pathway in Drosophila. |