INFLUENCE OF EPIGENETIC FACTORS IN THE CONTROL OF ENCYSTATION AND ANTIGENIC VARIATION IN GIARDIA

CARRANZA PG, , LUJÁN HD. TORRI A

Mendoza

Congreso; XLVIII Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2012

During eukaryotic evolution, parasites have faced the challenges of sensing and adapting to environmental and host insults to survive, colonize, and proliferate in a variety of species. , one of the most early-branching eukaryotes and a common cause of intestinal disease, has developed fascinating strategies to persist both outside and inside the intestine of its hosts, such as the encystation-excystation processes and surface antigenic variation. How these events are regulated remains poorly understood. This protozoan lacks several typical eukaryote features, such as canonical transcription factors, linker histone H1, complex promoter regions, relevant 5´- and 3´-UTR in mRNAs, among many other distinctive characteristics, suggesting that posttranscriptional and translational control of gene expression are key for the parasite biology. However, epigenetic factors may also play important roles in the regulation of gene expression. In this work, we describe the presence of common posttranslational histone modifications and their association with cell differentiation processes. We present evidence that the inhibition of the activity of NAD+-dependent and NAD+-independent histone Deacetylases abolishes encystation and increase the rate of switching of the Variant-specific Surface Proteins (VSPs) during antigenic variation of this important human pathogen.