Evolution of a trypanosome surface antigen gene repertoire linked to non-duplicative gene activation

M Laurent, E Pays, K Delinte, E Magnus, N Van Meirvenne, M Steinert

Research output: Contribution to journalA2: International peer reviewed article (not A1-type)

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.
Original languageEnglish
JournalNature
Volume308
Issue number5957
Pages (from-to)370-373
ISSN0028-0836
DOIs
Publication statusPublished - 1984

Keywords

  • B780-tropical-medicine
  • Protozoal diseases
  • Trypanosomiasis-African
  • Sleeping sickness
  • Trypanosoma brucei
  • Vectors
  • Tsetse flies
  • Glossina
  • Genes
  • Surface antigen
  • Repertoire
  • Conversion
  • Evolution

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