Activation of Su(Hw)-Controlled Genes Is Associated with Increase in GAF Binding.

The interaction of the GAF protein with the promoters of neuron-specific genes during activation and repression of transcription was studied. We showed that, while the Su(Hw) protein remains stably associated with the promoters of these genes at different transcriptional state, the GAF protein level is significantly higher when transcription is activated.

The same domain of Su(Hw) is required for enhancer blocking and direct promoter repression.

Suppressor of Hairy-wing [Su(Hw)] is a DNA-binding architectural protein that participates in the organization of insulators and repression of promoters in Drosophila. This protein contains acidic regions at both ends and a central cluster of 12 zinc finger domains, some of which are involved in the specific recognition of the binding site. One of the well-described in vivo function of Su(Hw) is the repression of transcription of neuronal genes in oocytes.

[Control of the gene activity by polycomb and trithorax group proteins in Drosophila].

Combinatorial expression of the genes in multicellular organisms leads to the development of different cell types. The important epigenetic regulators of higher eukaryotes are the Polycomb group (PcG) and Trithorax group (TrxG) proteins. These factors control the transcription of a large number of genes involved in various cellular processes.

The bxdPRE/TRE element terminates passing through transcription.

The regulation of PRE/TRE activity is required for appropriate tissue and stage-specific gene expression. However, the molecular principles of PRE/TRE activity control remain unknown. Here we show that PRE/TRE element from Ubx regulatory region efficiently terminates passing through transcription.

Role of Transcriptional Read-Through in PRE Activity in Drosophila melanogaster.

Maintenance of the individual patterns of gene expression in different cell types is required for the differentiation and development of multicellular organisms. Expression of many genes is controlled by Polycomb (PcG) and Trithorax (TrxG) group proteins that act through association with chromatin. PcG/TrxG are assembled on the DNA sequences termed PREs (Polycomb Response Elements), the activity of which can be modulated and switched from repression to activation.