Antigenic variation in African trypanosomes: the importance of chromosomal and nuclear context in VSG expression control. (10th October 2013)

• Record Type: Journal Article
• Authors: Glover, Lucy; Hutchinson, Sebastian; Alsford, Sam; McCulloch, Richard; Field, Mark C.; Horn, David
• Is Part Of: Cellular microbiology. Volume 15:Number 12(2013:Dec.)
• Page Start: 1984
• Page End: 1993
• Publication Date: 2013-10-10
• Subjects: Microbiology -- Periodicals; Cytology -- Periodicals; Host-parasite relationships -- Periodicals; Microbiology -- Periodicals; Cells -- Periodicals; Microbiologie -- Périodiques; Microbiologie; Relation hôte-parasite; Cytologie; Cellule; Réponse cellulaire; Ressource Internet (Descripteur de forme); Périodique électronique (Descripteur de forme); 579.05
• DOI: 10.1111/cmi.12215
• Languages: English
• ISSNs: 1462-5814

Abstract

<abstract abstract-type="main"> <title>Summary</title> <p>African trypanosomes are lethal human and animal parasites that use antigenic variation for evasion of host adaptive immunity. To facilitate antigenic variation, trypanosomes dedicate approximately one third of their nuclear genome, including many minichromosomes, and possibly all sub‐telomeres, to variant surface glycoprotein (VSG) genes and associated sequences. Antigenic variation requires transcription of a single <italic>VSG</italic> by RNA polymerase I (Pol‐I), with silencing of other <italic>VSG</italic>s, and periodic switching of the expressed gene, typically via DNA recombination with duplicative translocation of a new <italic>VSG</italic> to the active site. Thus, telomeric location, epigenetic controls and monoallelic transcription by Pol‐I at an extranucleolar site are prominent features of <italic>VSG</italic>s and their expression, with telomeres, chromatin structure and nuclear organization all making vitally important contributions to monoallelic <italic>VSG</italic> expression control and switching. We discuss <italic>VSG</italic> transcription, recombination and replication control within this chromosomal and sub‐nuclear context.</p> </abstract>