Expression of oat arginine decarboxilase (ADC) gene in Trypanosoma cruzi epimastigotes

SERRA MP; CARRILLO C; HUBER MA; GONZÁLEZ NS; ALGRANATI ID

Bariloche, Rio Negro, Argentina

Congreso; XXXIX Reunión Anual de la SAIB; 2003

SAIB

EXPRESSION OF OAT ARGININE DECARBOXYLASE (ADC) GENE IN TRYPANOSOMA CRUZI EPIMASTIGOTES. M.P. Serra, C. Carrillo, A. Huber, N.S. González and I.D. Algranati. Fundación Insttituto Leloir y Facultad de Ciencias exactas y Naturales (UBA).e-mail:ialgranati@leloir.org.ar   Trypanosoma cruzi epimastigotes cultivated in a semisynthetic medium can normally proliferate only when putrescine or spermidine is added to the medium. This auxotrophy for polyamines is caused by parasite inability to synthesize putrescine. Previous work from our laboratory has shown that wild-type strains of T. cruzi do not contain ornithine decarboxilase (ODC) enzymatic activity due to the absence of the corresponding gene in the parasite genome. Recent experiments carried out to search for the putative conversion of arginine into agmatine, which would allow putrescine biosynthesis through the only other possible metabolic pathway leading to polyamines, also gave negative results in all the strains of T. cruzi assayed. We were able to demonstrate that the absence of ADC enzymatic activity in wild-type T. cruzi is not caused by inhibition of the enzyme expression inside the parasite. In fact after transfections of T. cruzi with a recombinant plasmid bearing the coding region of oat ADC inserted in an appropriate vector, we have obtained transgenic T. cruzi showing an appreciable level of transient expression of ADC enzymatic activity. The heterologous ADC has been characterized by identification of its products, agmatine and CO2, as well as by the stoichiometry of the catalysed reaction and the specific inhibition by difluoromethylarginine (DFMA).