The involvment of Giardia lamblia SF2 of RNA helicases during encystation and antigenic variation

GARGANTINI PABLO; SERRADELL MARIANELA C; ALESSANDRO TORRI; LUJAN HUGO DANIEL

Potrero de los Funes, San Luis

Congreso; XLVII Reunion Anual de la Sociedad Argentina de Investigacion en Bioquimica y Biologia Molecular. SAIB; 2011

Helicases are encoded by a large fraction of eukaryotic and prokaryotic genomes and they play important roles in almost every cellular mechanism that involves nucleic acids. On the other hand, RNA is involved in virtually all aspects of gene expression, playing important regulatory roles in biological reactions. Giardia shows two important mechanisms of adaptation to survive both outside and inside the host´s intestine, which are ?encystation? and ?antigenic variation?, respectively. We analyzed the expression of some RNA helicases by qPCR, looking for the involvement of these genes on both process. The relative expressions of these genes were determined in trophozoites after incubation for 16 hours in encystation medium. For the antigenic variation, trophozoites were incubated at short times with a specific antibody recognizing the unique VSP expressed in their surface. We found 4 genes down-regulated and 14 genes up-regulated during encystation. And during antigenic variation at short times, we found 3 genes up-regulated and 5 down-regulated within 1 hour, and 8 genes that were up-regulated and 4 down-regulated at 4 hours after the incubation with the specific antibody. The large DExD/H-box helicase family in Giardia could present this differential expression and regulation, being the cornerstone for the RNA metabolism and signaling in this parasite.