Poster abstracts
Poster number 148 submitted by Arpita Saha
Understanding the role of telomeric long non-coding RNA, TERRA, in Trypanosoma brucei
Arpita Saha (GRHD, BGES), Bibo Li (GRHD, BGES)
Abstract:
The flagellated protozoan parasite Trypanosoma brucei causes human African trypanosomiasis. The parasite utilizes sophisticated antigenic variation – regular switching of its major surface antigen coat (VSGs) – to survive the immune response of the host. There are > 2,500 VSG genes in the T. brucei genome although only one is expressed at any time from one of the ~ 20 VSG expression sites (ESs) located at the subtelomeric regions. Telomeres are nucleoprotein complexes at chromosome ends. They are essential for genomic integrity and chromosome stability. Telomeric RNA, TERRA, has heterogenous sizes that range from 100 bp to 9 kb. It was first reported in T. brucei and later in yeast and vertebrates. We recently showed that T. brucei TERRA is transcribed as a readthrough transcript from the active ES-adjacent telomere. In addition, excessive amount of TERRA leads to more frequent VSG switching events. As a lncRNA, TERRA may also play an important role in VSG expression regulation. To better understand the functions of TERRA in antigenic variation, we intend to determine the TERRA protein interactome by performing iDRIP (direct RNA-protein interaction in vivo), which is a comprehensive approach aiming to capture the whole RNA-protein interactome. We are currently testing various pull-down conditions. Additionally, our preliminary IF and RNA FISH results showed that TERRA co-localizes with TbTRF, the duplex telomere DNA binding protein in T. brucei, which is consistent with the observation that TbTRF binds TERRA directly. Our study will help better understand the role of TERRA in antigenic variation and in maintaining telomere/subtelomere integrity.
Keywords: TERRA, Trypanosoma brucei, telomere integrity