[Chromosome structure, histones and gene activity in Drosophila].

The problem to be reviewed in this study concerns the mechanism of regulation of gene activity relied on the structural changes of the chromatin. The role of histones in the regulation of transcription is discussed on the basis of the results obtained by the authors and literature data. In particular, the results are presented of the investigations of decrease of the histone amount in the cell nucleus using the deficiency of histone structural genes. This leads both to the increase of the X-chromosome template activity and the inhibition of variegated position effect. The latter is also inhibited by feeding of larvae with T2-DNA. It is supposed that the chromatin structure is a mechanism of epigenetic changes and the gene inactivation due to the position effect inherited in cell lineages in an example of such epigenetic changes.