NUCLEAR PROTEIN IMPORT IN TRYPANOSOMA BRUCEI

MEYER CG; TORRES HN; FLAWIÁ MM; ALONSO GD

San Miguel de Tucumán. Tucumán, Argentina.

Congreso; XLV Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB).; 2009

In eukaryotic cells, the nuclear envelope provides a physical separation between the nucleus and the cytoplasm allowing the precise control of cellular processes as gene expression, signal transduction and cell cycle progression by selectively regulating transport between both compartments. This regulation necessitates the existence of molecular machinery that specifically recognizes a protein in one compartment and translocates it through the nuclear pore to release it in the other compartment. The active transport of macromolecular cargo between the cytoplasmic and nuclear compartments is achieved by specific soluble carrier proteins called karyopherins, with those involved in import termed importins. The alpha subunit of importin binds the nuclear localization signal (NLS) in the cytosol and the beta subunit docks this complex at the cytoplasmatic side of the nuclear pore complex. So far nuclear import machinery in Trypanosomatids has no been described and NLS are barely known in these organisms. We found that Trypanosoma brucei genome encodes a putative Alpha Importin of predicted 58 kDa and a putative Beta Importin of predicted 95 kDa. Both proteins were cloned as fusion proteins to YFP, Cherry FP and HA tag to study subcellular localization and dynamics. We are also performing RNAi experiments using p2T7-177 vector to evaluate the viability of the transfected parasites.