Characterization of ADAT2/3 molecules in Trypanosoma cruzi and regulation of mucin gene expression by tRNA editing.
Bertotti, S., Fleming, I., Camara, M. L. M., Centeno Camean, C., Carmona, S. J., Aguero, F., Balouz, V., Zahn, A., Di Noia, J. M., Alfonzo, J. D. and Buscaglia, C. A.
Laboratory of Molecular Biology of Protozoa, Instituto de Investigaciones Biotecnologicas 'Dr Rodolfo Ugalde' (IIBio, Universidad Nacional de San Martin, UNSAM, and Consejo Nacional de Investigaciones Cientificas y Tecnicas, CONICET), Av. 25 de Mayo y Francia, Campus UNSAM, San Martin (1650), Buenos Aires, Argentina.
Department of Microbiology, The Ohio State University, 318 W 12th Ave. (Aronoff Building), Columbus, U.S.A.
Trypanosomatics Laboratory, IIBio (UNSAM and CONICET), Buenos Aires, Argentina.
Institut de Recherches Cliniques de Montreal (IRCM), Montreal, Quebec, Canada.
Department of Medicine, University of Montreal, Montreal, Quebec, Canada.
Adenosine-to-inosine conversion at position 34 (A34-to-I) of certain tRNAs is essential for expanding their decoding capacity. This reaction is catalyzed by the adenosine deaminase acting on tRNA (ADAT) complex, which in Eukarya is formed by two subunits: ADAT2 and ADAT3. We herein identified and thoroughly characterized the ADAT molecules from the protozoan pathogen Trypanosoma cruzi, the causative agent of Chagas Disease. TcADAT2 and TcADAT3 spontaneously form a catalytically active complex, as shown by expression in engineered bacteria and/or by the increased ex vivo tRNA A-to-I deamination activity of T. cruzi epimastigotes overexpressing TcADAT subunits. Importantly, enhanced TcADAT2/3 activity in transgenic parasites caused a shift in their in vivo tRNAThrAGU signature, which correlated with significant changes in the expression of the Thr-rich TcSMUG proteins. To our knowledge, this is the first evidence indicating that T. cruzi tRNA editing can be modulated in vivo, in turn post-transcriptionally changing the expression of specific genes. Our findings suggest tRNA editing/availability as a forcible step in controlling gene expression and driving codon adaptation in T. cruzi. Moreover, we unveil certain differences between parasite and mammalian host tRNA editing and processing, such as cytosine-to-uridine conversion at position 32 of tRNAThrAGU in T. cruzi, that may be exploited for the identification of novel druggable targets of intervention.
The Biochemical Journal 479(4): 561-580 (2022)