The nuclear matrix protein EAST affects the transcription of Drosophila melanogaster genes irrespective of the presence of retrotransposon MDG4 sequences

Abstract

Our recent study demonstrated that alteration of expression of the east gene affects the transcription of the yellow gene of Drosophila melanogaster. Furthermore, this influence was shown to be associated with the presence of retrotransposon MDG4 sequences in the pre-promoter gene region. In the present study, we analyzed the effects of different concentrations of EAST protein on the expression of different genes of Drosophila. In addition, it was analyzed whether this effect was associated with the presence of MDG4 in the allelic gene variant of interest. It was demonstrated that the effect of EAST protein on the expression of different genes was not always directly associated with the presence of MDG4 sequences. For instance, an increase in the EAST concentration had no effect on the expression of mutant alleles of the achaete-scute complex, some of which contained the MDG4 sequences. Moreover, enhancement of the east expression resulted in the alteration of the phenotypic manifestation of the mutant allele of the cut locus irrespective of the presence of MDG4. Finally, the alteration of the EAST concentrations had no substantial effect on transgene repression if they were inserted either in heterochromatin or in telomeric regions of chromosome 4, as well as on the repression induced by Polycomb group proteins. The data obtained suggested that EAST protein belonged to a new regulatory system, which was common to most of the genes, and repressed transcription of the genes located in the euchromatin regions of the chromosomes.