Evolution of a trypanosome surface antigen gene repertoire linked to non-duplicative gene activation
- 1 March 1984
- journal article
- Published by Springer Nature in Nature
- Vol. 308 (5957) , 370-373
- https://doi.org/10.1038/308370a0
Abstract
African trypanosomes activate, one at a time, a large set of genes coding for different variant-specific surface antigens (VSAs). These genes have been classed into two groups. In the first group a permanently silent basic gene copy is duplicated and the expression-linked copy (ELC) transposed to an expression site located at a chromosome end. The process is a gene conversion which changes a variable stretch of the preceding ELC. Genes belonging to the second group do not give rise to an additional copy when expressed by a still unknown mechanism. We report here that the gene for antigenic type AnTat 1.6 is located in a telomeric DNA region and is expressed without being duplicated. In clone AnTat 1.6 and the ensuing ones, the ELC of the preceding VSA (AnTat 1.3) is conserved, but in a inactive conformation. Moreover, the AnTat 1.6 gene is lost from the genome of the AnTat 1.6-derived variants, in which the duplication-linked mechanism of gene activation occurs: the gene appears to be replaced by the incoming ELC. These observations show that a trypanosome surface antigen repertoire may evolve by loss and gain of VSA genes, depending on the alternation of the different recombinational mechanism involved in antigenic variation.Keywords
This publication has 18 references indexed in Scilit:
- Gene conversion as a mechanism for antigenic variation in TrypanosomesCell, 1983
- Relationship between multiple copies of a T. brucei variable surface glycoprotein gene whose expression is not controlled by duplicationCell, 1983
- DNA rearrangements linked to expression of a predominant surface antigen gene of trypanosomesNature, 1983
- Genomic environment of T. brucei VSG genes: presence of a minichromosomeNature, 1982
- Two distinct forms of surface antigen gene rearrangement in Trypanosoma bruceiNature, 1982
- Molecular basis for trypanosome antigenic variationCell, 1982
- Analysis of genomic rearrangements associated with two variable antigen genes of Trypanosoma bruceiNucleic Acids Research, 1982
- Activation of trypanosome surface glycoprotein genes involves a duplication-transposition leading to an altered 3′ endCell, 1981
- Gene duplication and transposition linked to antigenic variation in Trypanosoma brucei.Proceedings of the National Academy of Sciences, 1981
- Novel expression-linked copies of the genes for variant surface antigens in trypanosomesNature, 1980