The Trypanosoma brucei RNA Binding Protein Tb RRM 1 is Involved in the Transcription of a Subset of RNA Pol II ‐Dependent Genes

BAÑUELOS, CAROLINA P.; LEVY, GABRIELA V.; NÍTTOLO, ANALÍA G.; ROSER, LEANDRO G.; TEKIEL, VALERIA; SÁNCHEZ, DANIEL O.

JOURNAL OF EUKARYOTIC MICROBIOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2019

1066-5234

It has been long thought that RNA Polymerase (Pol) II transcriptional regulationdoes not operate in trypanosomes. However, recent reports have suggestedthat these organisms could regulate RNA Pol II transcription by epigeneticmechanisms. In this paper, we investigated the role of TbRRM1 in transcriptionalregulation of RNA Pol II-dependent genes by focusing both in geneslocated in a particular polycistronic transcription unit (PTU) and in the monocistronicunits of the SL-RNA genes. We showed that TbRRM1 is recruitedthroughout the PTU, with a higher presence on genes than intergenic regions.However, its depletion leads both to the decrease of nascent RNA and tochromatin compaction only of regions located distal to the main transcriptionstart site. These findings suggest that TbRRM1 facilitates the RNA Pol II transcriptionalelongation step by collaborating to maintain an open chromatin statein particular regions of the genome. Interestingly, the SL-RNA genes do notrecruit TbRRM1 and, after TbRRM1 knockdown, nascent SL-RNAs accumulatewhile the chromatin state of these regions remains unchanged. Although itwas previously suggested that TbRRM1 could regulate RNA Pol II-drivengenes, we provide here the first experimental evidence which involvesTbRRM1 to transcriptional regulation.DOI: 10.1111/jeu.12716