The SR protein B52/SRp55 is required for DNA topoisomerase I recruitment to chromatin, mRNA release and transcription shutdown.

ABSTRACT: DNA- and RNA-processing pathways are integrated and interconnected in the eukaryotic nucleus to allow efficient gene expression and to maintain genomic stability. The recruitment of DNA Topoisomerase I (Topo I), an enzyme controlling DNA supercoiling and acting as a specific kinase for the SR-protein family of splicing factors, to highly transcribed loci represents a mechanism by which transcription and processing can be coordinated and genomic instability avoided. Here we show that Drosophila Topo I associates with and phosphorylates the SR protein B52. Surprisingly, expression of a high-affinity binding site for B52 in transgenic flies restricted localization, not only of B52, but also of Topo I to this single transcription site, whereas B52 RNAi knockdown induced mis-localization of Top

SUBMITTER: Juge F 

PROVIDER: S-EPMC2940736 | biostudies-literature | 2010 Sep

REPOSITORIES: biostudies-literature