Expression of both genes of reversibly glycosylated polypeptide of rice plants

VERÓNICA DE PINO; SILVIA MORENO

Puerto Iguazu. Misiones

Congreso; XXXXI Reunion de la Sociedad Argentina de Investigaciones en Bioquímica y Biología Molecular; 2004

Sociedad Argentina de Investigaciones en Bioquímica y Biología Molecular

EXPRESSION OF BOTH GENE OF REVERSIBLY GLYCOSYLATED POLYPEPTIDE OF RICE PLANTS Verónica De Pino and Silvia Moreno Fundación Instituto Leloir (formerly “Fundación Campomar”), Instituto de Investigaciones Bioquímicas, Buenos Aires- CONICET. Patricias Argentinas 435, (1405) Buenos Aires, Argentina. E-mail : smoreno@leloir.org.ar   Reversibly glycosylated polypeptides (RGPs) are involved in plant polysaccharide synthesis such as in hemicellulose and starch synthesis [1]. Previously, we reported the presence of an RGP protein in rice (Oryza sativa) seeds and in vitro plants which posse activity upon incubation with UDP-Glc, UDP-Xyl, UDP-Gal. When OsRGP reaction was carried out in the presence of UDP-[14C]Glc as sugar  donor   and   then  1 mM UDP was added in a chase-out experiment, we observed that OsRGP reaction seems to be reversible. Here, we studied the expression of the RGP protein in ungerminated seeds, early-germinated seeds (two days of culture), or in vitro plants (5, 8 and 10 days of culture) with the aim to analyze protein regulation. Also, we investigate whether the protein is regulated by hormone involved in plant growing.  We found a clear activity and protein induction after AIA+BAP treatment. Different plant developmental states shown different electrophoretic mobility of the 38-kDa subunit. In order to investigate if a post traducctional modification or different isoforms are present, we perform northern blot analysis using two specific probes corresponding to both genes described in rice (RGP1 and RGP2). We conclude that OsRGPs polypeptides are developmentally and also hormonally regulated.