Trm11p and Trm112p Are both Required for the Formation of 2-Methylguanosine at Position 10 in Yeast tRNA

Abstract

N²-Monomethylguanosine-10 (m²G10) and N² ,N²-dimethylguanosine-26 (m² ₂G26) are the only two guanosine modifications that have been detected in tRNA from nearly all archaea and eukaryotes but not in bacteria. In Saccharomyces cerevisiae, formation of m² ₂G26 is catalyzed by Trm1p, and we report here the identification of the enzymatic activity that catalyzes the formation of m²G10 in yeast tRNA. It is composed of at least two subunits that are associated in vivo: Trm11p (Yol124c), which is the catalytic subunit, and Trm112p (Ynr046w), a putative zinc-binding protein. While deletion of TRM11 has no detectable phenotype under laboratory conditions, deletion of TRM112 leads to a severe growth defect, suggesting that it has additional functions in the cell. Indeed, Trm112p is associated with at least four proteins: two tRNA methyltransferases (Trm9p and Trm11p), one putative protein methyltransferase (Mtc6p/Ydr140w), and one protein with a Rossmann fold dehydrogenase domain (Lys9p/Ynr050c). In addition, TRM11 interacts genetically with TRM1, thus suggesting that the absence of m²G10 and m² ₂G26 affects tRNA metabolism or functioning.

SUPPLEMENTAL MATERIAL

Supplemental material for this article may be found at http://mcb.asm.org/.

ACKNOWLEDGMENTS

We thank E. Bertrand, R. Bordonné, and M. Sitbon for stimulating discussions. We are grateful to E. Schwob and L. Dirick for their help with yeast analysis and for sharing supplies and equipment.

This work was supported by a grant from the Association pour la Recherche sur le Cancer (no. 5914), the Fondation pour la Recherche Médicale, the Ligue Nationale contre le Cancer, and the Centre National de la Recherche Scientifique. J.M.B. was supported by a EMBO/HHMI Young Investigator award and by a fellowship from the Foundation for Polish Science. H.G. was supported by a grant from the CNRS (Programme Interdépartemental de Géomicrobiologie des Environnements Extrêmes, Geomex 2002-2003). S.K.P. was a fellow from the Ministère des Affaires étrangères and then from the Ligue Nationale contre le Cancer.