Fundamental Nuclear Factors complexes in Trypanosoma cruzi. Mesa Redonda: Molecular and Cellular Biology Aspects of Trypanosomes.

ESTEBAN SERRA; ANDREA TROCHINE; VANINA VILLANOVA; PAMELA CRIBB

Caxambu - Brasil

Congreso; XXII Annual Meeting of the Brazilian Society of Protozoology. XXXIII Annual Meeting on Basic Research in Chagas´Disease; 2006

Sociedad Brasilera de Protozoología

Even though little is known about transcription in Trypanosomes, enough evidence has been achieved to show unique characteristics, different from those present in other eukaryotes. Due to the lack of true regulatory transcription factors, the assembly of the basal factor complexes, and its interaction with the RNA polymerases (RNPs), chromatin proteins and DNA, seems to be the major regulatory events at the transcription initiation level. Nevertheless, post-transcriptional control remains the most plausible fine tune regulatory mechanism. A number of ortologues of basal nuclear factors were detected experimentally and by data mining of the TriTryp genomes. In our laboratory, we amplified nearly twenty T. cruzi CDCs considered as basal factors implicated in RNAP II y RNAP III transcription. These sequences were cloned into pENTR vectors from the Gateway TM System (Invitrogen) and introduced by recombination to different destination vectors. Interactions among factors were assayed by Two-hybrid System. The most strong interaction detected was between TcTBP and TFIIB-related factor TcBFR. This interaction was mapped at the TcBRF C-terminal domain, and the first repeat of TcTBP. In contrast, TcTBP and TcTFIIB interaction probed to be weak. All currently known components of the SL-binding complex were also assayed for interaction by the same technique. TcTBP showed interaction with TcSNAP50 and TcTFIIA2. As expected, TcSNAP50 interacts with TcSNAP46. These results, with a number of low intensity interactions also detected, allowed us to propose a model for the architecture of the complex.