VSG switching in Trypanosoma brucei: antigenic variation analysed using RNAi in the absence of immune selection.

ABSTRACT: Trypanosoma brucei relies on antigenic variation of its variant surface glycoprotein (VSG) coat for survival. We show that VSG switching can be efficiently studied in vitro using VSG RNAi in place of an immune system to select for switch variants. Contrary to models predicting an instant switch after inhibition of VSG synthesis, switching was not induced by VSG RNAi and occurred at a rate of 10(-4) per division. We find a highly reproducible hierarchy of VSG activation, which appears to be capable of resetting, whereby more than half of the switch events over 12 experiments were to one of two VSGs. We characterized switched clones according to switch mechanism using marker genes in the active VSG expression site (ES). Transcriptional switches between ESs were the preferred switching mechan

SUBMITTER: Aitcheson N 

PROVIDER: S-EPMC1618954 | biostudies-literature | 2005 Sep

REPOSITORIES: biostudies-literature