Posttranscriptional mechanisms involved in the control of expression of the stage-specific GP82 surface glycoprotein in Trypanosoma cruzi
Data
2009-02-01
Autores
Gentil, Luciana Girotto 
Cordero, Esteban Mauricio
Carmo, Mirian Silva do
Machado dos Santos, Marcia Regina
Silveira, Jose Franco da
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Artigo
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Resumo
Trypanosoma cruzi metacyclic trypomastigotes express the developmentally regulated GP82 glycoprotein, which is implicated in host cell invasion. Although GP82 mRNA and protein are not present and the mRNAs barely detectable in epimastigotes, nuclear run-on analysis showed that it is transcribed in both stages. This result indicates that accumulation of transcripts in metacyclic forms is not due to increased transcription of the GP82 gene. To investigate whether mRNA stability may be responsible for the differences in the steady-state levels of this mRNA, parasites were treated with actinomycin D or cycloheximide. When treated with actinomycin D, the half-lives estimated for GP82 transcripts were about 6 h ill metacyclic trypmastigotes and 0.5 h in epimastigotes. in the presence of cycloheximide, the levels of GP82 mRNA decayed slightly after 8 h in metacyclic trypomastigotes, whereas in epimastigotes the levels of this mRNA increased. This effect suggests a stabilizing mechanism acting in metacyclic trypomastigotes and a destabilizing mechanism in epimastigotes which Could be mediated by an element present in the 3'-UTR of the transcripts. Consistent with this finding, northern blot analysis showed that GP82 mRNAs were mobilized to polysomes and consequently translated, but only in metacyclic trypomastigotes. (C) 2008 Elsevier B.V. All rights reserved.
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Citação
Acta Tropica. Amsterdam: Elsevier B.V., v. 109, n. 2, p. 152-158, 2009.