Complexity of P proteins interactions in the ribosomal stalk of Trypanosoma cruzi.

MAXIMILIANO JURI AYUB; MARTIN EDREIRA; CRISTIAN SMULSKI; CRISTIAN ROCHA; MARIANO LEVIN

San Carlos de Bariloche, Argentina

Congreso; XXXIX Reunion Anual de la Sociedad Argentina de Investigacion en Bioqumica y Biologia Molecular; 2003

Sociedad Argentina de Investigacion en Bioquimica y Biologia Molecular

In all eukaryotic cells, ribosomal P proteins form a lateral protuberance, which is directly involved in translation process. The number of classes and subclasses of P proteins is variable from species to species. In Trypanosoma cruzi, P1, P2á and P2â genes have been cloned. Interactions among these P proteins were evaluated by native PAGE and yeast two hybrid assays, showing strong interaction between P1 and P2â. However, the spatial arrangement of the pentameric P complex remains uncertain. Here we report evidences for the presence of other P proteins. Western blot assays of T cruzi lysates developed with a monoclonal antibody against the conserved C terminal peptide (R13) showed four bands in the 14-20 kDa range. One of these bands was identified as P2â by a specific monoclonal antibody. Moreover, algorithms corresponding to the consensus C terminal region of P proteins were used to search in the last version of the nucleotide TIGR database. This search showed the presence of at least one new class of P protein in a locus containing two copies in tandem. The new P protein was found in the EST database suggesting that this gene is expressed, at least at mRNA level. The protein sequence identity is 40% with P1, 35.8% with P2á and 28.8% with P2â.