Rab1 GTPase Modulates the expression of genes involved in protein trafficking

ROMERO, NAHUEL; DUMUR, CATHERINE; MONETTA, PABLO M; SLAVIN ILEANA AND ALVAREZ, CECILIA

Rosario, Santa Fe, Argentina

Congreso; SAIB; 2006

SAIB

Rab1 GTPase Modulates the expression of genes involved in protein trafficking Romero, Nahuel; Dumur, Catherine; Monetta, Pablo M; Slavin Ileana and Alvarez, Cecilia The GTPase Rab1 is essential for Endoplasmic Reticulum to Golgi transport.  By using genome-wide microarray analysis on HeLa cells expressing Rab1 and mutants we have identified (SAIB 2005) specific Rab1 dependent changes of gene transcription.  Results showed that about 300 probe sets were significantly regulated by expression of Rab1.  Here, different non-related criterions were used to select interesting genes, from the reported microarray results, to be validated by quantitative R90 T-PCR (TaqMan).  Genes that code for proteins involved in membrane traffic (6), transcription factors (2), and two proteins used as controls, were selected.  Our results showed that quantitative RT-PCR results showed very good correlation with Affymetrix values (Pearson´s r > 0.6 in most cases).  Moreover, western blot analysis (using inducible-stable transfected Rab1 cell line) indicated that quantity of proteins coded for three of the selected genes, was also increased in a Rab1-dependent manner.  Finally, to define if expression of Rab1 modulated-genes is achieved by signaling pathways involving the proximal promoter region, they were cloned into a luciferase reporter plasmid and the promoter activity was evaluated in Rab1 inducible-stable transfected cell line.  Our study aims to understand the molecular mechanisms that may explain how Rab1 modulates expression of genes related to protein trafficking.