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Multiple events associated with antigenic switching in Trypanosoma brucei
P J Myler1, R F Aline, J K Scholler
1Seattle Biomedical Research Institute, WA 98109-1651.
Molecular and Biochemical Parasitology
|June 1, 1988
Summary
Trypanosoma brucei variant surface glycoprotein (VSG) gene families reside in distinct telomeric sites. Antigenic switching is explained by gene conversion and telomeric activation, often in combination.
Area of Science:
- Molecular biology
- Genetics
- Parasitology
Background:
- Trypanosoma brucei evades the host immune system through antigenic variation.
- Variant surface glycoprotein (VSG) genes are key to this immune evasion strategy.
Purpose of the Study:
- To characterize the genomic locations of VSG gene families in Trypanosoma brucei.
- To understand the mechanisms driving antigenic switching in Trypanosoma brucei.
Main Methods:
- Southern blot analysis of DNA.
- Conventional and pulse field gradient electrophoresis.
- Analysis of VSG gene locations in antigenic variants.
Main Results:
- Identified 9 distinct telomeric sites housing VSG genes across 7 chromosomes.
- VSG genes are expressed from at least 6 telomeric locations.
- Antigenic switches result from gene conversion and/or telomeric activation.
Conclusions:
- VSG gene organization provides a basis for antigenic variation.
- Gene conversion and telomeric activation are the primary mechanisms of antigenic switching.
- Combined processes contribute significantly to antigenic switching frequency.