TRYPANOSOMA CRUZI BASAL TRANSCRIPTION FACTORS IN THE POST GENOMIC ERA

CRIBB PAMELA; TROCHINE ANDREA; ESTEBAN SERRA

Iguazú, Misiones, Argentina

Congreso; XL Annual Meeting Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2004

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

TRYPANOSOMA CRUZI BASAL TRANSCRIPTION FACTORS IN THE POST GENOMIC ERA Pamela Cribb; Andrea Trochine; Esteban Serra. IBR-Fac. Cs. Bioq. y Farm. UNR. . eserra@arnet.com.ar For a long time it has been accepted that gene expression in trypanosomatids was almost exclusively post-transcriptional. However, in the last years, the description of several transcription factors in these organisms, as well as the determination of a transcription initiation region in Leishmania chromosomes, has led to the idea that transcription may be controled, at least to some extent, at the initiation level. In our laboratory we have cloned and characterized a TATA-binding protein from T. cruzi (TcTBP)  This protein has shown to take part in a complex that binds the SL-RNA gene promoter, the only RNAPol II-dependent promoter described in trypanosomatids. Other protein complexes required for SL-RNA transcription, characterized in related organisms, have been found in T. cruzi too. In order to determine the composition and structure of the transcription initiation complexes in this parasite, we performed both homology- and motif- based searches in the available T. cruzi genomic sequences. We identified several putative basal transcription factors, related to RNAPol II and RNAPol III promoters. The coding sequences of these factors were PCR-amplified and cloned into Two hybrid vectors to analize the interactions between them. TcTBP showed interaction with many of the new cloned basal factors, suggesting that it takes part in different initiation complexes, as seen for TBPs from higher eukariotes.