Nucleosomes are depleted at the VSG expression site transcribed by RNA polymerase I in African trypanosomes.

ABSTRACT: In most eukaryotes, RNA polymerase I (Pol I) exclusively transcribes long arrays of identical rRNA genes (ribosomal DNA [rDNA]). African trypanosomes have the unique property of using Pol I to also transcribe the variant surface glycoprotein VSG genes. VSGs are important virulence factors because their switching allows trypanosomes to escape the host immune system, a mechanism known as antigenic variation. Only one VSG is transcribed at a time from one of 15 bloodstream-form expression sites (BESs). Although it is clear that switching among BESs does not involve DNA rearrangements and that regulation is probably epigenetic, it remains unknown why BESs are transcribed by Pol I and what roles are played by chromatin structure and histone modifications. Using chromatin immunoprecipitation, mi

SUBMITTER: Figueiredo LM 

PROVIDER: S-EPMC2805297 | biostudies-literature | 2010 Jan

REPOSITORIES: biostudies-literature