Project name: Genome-wide function of MCM-BP in Trypanosoma brucei DNA replication and transcription

Description: In Trypanosoma brucei, genes are arranged in Polycistronic Transcription Units (PTUs), which are demarcated by transcription start and stop sites. Transcription start sites are also binding sites of Origin Recognition Complex 1 (ORC1). These suggest that transcription and replication in trypanosomes must occur in highly ordered and cooperative manners. Not coincidently, our previous genetic screen, a LOss of transcription Silencing (LOS) screen, identified a T. brucei MCM-BP, which forms a complex with subunits of the replicative helicase MCM. Here, I show that TbMCM-BP is required for DNA replication and transcription. TbMCM-BP depletion causes a significant reduction of replicating cells in S phase and genome-wide impairments of replication origin activation. Moreover, levels of sense and antisense transcripts increase at boundaries of PTUs in the absence of TbMCM-BP. TbMCM-BP is also important for transcriptional repression of the specialized subtelomeric PTUs, the Bloodstream-form Expression-Sites (BESs), which house the gene of antigenic importance, VSG. In the absence of TbMCM-BP, expression of silent VSGs is elevated, silent promoter regions are derepressed, and antisense transcription increases downstream of the silent promoters. This study reveals that TbMCM-BP, a replication initiation protein, guides transcription to properly start and stop, and also helps it move in the correct direction.Overall design: For RNAseq, sample for each time point have four replicates. For MFAseq, one sample per each time point was used, and FACS sorted at G1, early S (S1), late S (S2) and G2.Please note that the associated processed data files are indicated in the corresponding sample description field and the readme.txt contains a brief description of the data content for each file.

Data type: Other

Sample scope: Multiisolate

Relevance: Medical

Last updated: 2018-08-07