CG10543 Protein Is Involved in the Regulation of Transcription of Ecdysone-Dependent Genes

Despite increasing data on the properties of the origins of replication, the molecular mechanisms underlying the origin recognition complex (ORC) positioning in the genome are still poorly understood. It has been suggested that the key factors determining the positioning of ORC in the genome are DNA-binding proteins that form various DNA regulatory elements, including insulators, promoters, and enhancers, thereby linking the replication program to different levels of transcriptional regulation. Previously, we demonstrated that the Su(Hw) protein is the first example of such a protein. Subsequent studies identified a number of other DNA-binding proteins, including CG10543, which may be responsible for the formation of the corresponding regulatory elements and the recruitment of transcriptional and replication complexes to their binding sites. It has been shown that the Drosophila CG10543 protein interacts with the deubiquitinating (DUB) module of the SAGA complex. The binding sites of the CG10543 protein are predominantly located in the promoter regions of active genes and colocalize with the SAGA and dSWI/SNF chromatin modification and remodeling complexes, as well as with the ORC replication complex. To investigate the role of the CG10543 protein in transcriptional regulation, an RNA-Seq experiment was conducted in Drosophila S2 cells under normal conditions and upon RNA interference with the CG10543 protein. It was shown that the CG10543 protein affects the transcription of 469 genes, with a significant portion of these genes (23%) being ecdysone-dependent genes. Ecdysone is the main steroid hormone in Drosophila, is responsible for Drosophila metamorphosis, and has a significant effect on the expression of many genes during development. We demonstrated that CG10543 sites colocalize with the CBP protein and the histone mark H3K27Ac, which are characteristic of active regulatory elements. The CG10543 protein also colocalizes with the CP190 protein, suggesting a potential mechanism of transcriptional regulation through the formation of long-range interactions between regulatory elements.