ABSTRACTWe have shown that tubulin mRNA accumulation is regulated at the transcriptional level during metacyclogenesis ofTrypanosoma cruzi, although the contribution of post-transcriptional mechanisms is also indicated. mRNA heterogeneity is not restricted to β-tubulin, and differential regulation of α-tubulin mRNAs is observed during this stage of the parasite's life cycle. Treatment of epimastigotes with the microtubule-depolymerizing agent vinblastine resulted in growth inhibition and morphological alterations. Vinblastine also induced a rise in the pool of free tubulin subunits, concomitant with diminished tubulin synthesis and reduced mRNA levels. Tubulin gene transcription remained unaltered during vinblastine treatment, suggesting post-transcriptional control. These observations are in agreement with the autoregulatory model of tubulin gene expression described for a variety of cell types. We conclude thatT. cruziutilizes transcriptional and post-transcriptional control mechanisms for tubulin gene expressio
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