Trypanosoma brucei: posttranscriptional control of the variable surface glycoprotein gene expression site.
AUTOR(ES)
Pays, E
RESUMO
The arrest of variable surface glycoprotein (VSG) synthesis is one of the first events accompanying the differentiation of Trypanosoma brucei bloodstream forms into procyclic forms, which are characteristic of the insect vector. This is because of a very fast inhibition of VSG gene transcription which occurs as soon as the temperature is lowered. We report that this effect is probably not controlled at the level of transcription initiation, since the beginning of the VSG gene expression site, about 45 kilobases upstream from the antigen gene, remains transcribed in procyclic forms. The permanent activity of the promoter readily accounts for the systematic reappearance, upon return to the bloodstream form after cyclical transmission, of the antigen type present before passage to the tsetse fly. The abortive transcription of the VSG gene expression site appears linked to RNA processing abnormalities. Such posttranscriptional controls may allow the modulation of gene expression in a genome organized in large multigenic transcription units.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=362464Documentos Relacionados
- Trypanosoma brucei: enrichment by UV of intergenic transcripts from the variable surface glycoprotein gene expression site.
- Trypanosoma brucei brucei: inhibition of glycosylation of the major variable surface coat glycoprotein by tunicamycin.
- Transient activity assays of the Trypanosoma brucei variant surface glycoprotein gene promoter: control of gene expression at the posttranscriptional level.
- The promoter for a variant surface glycoprotein gene expression site in Trypanosoma brucei.
- A transferrin-binding protein of Trypanosoma brucei is encoded by one of the genes in the variant surface glycoprotein gene expression site.