title: Actin-binding protein ABP140 is a methyltransferase for 3-methylcytidine at position 32 of tRNAs in Saccharomyces cerevisiae.
abstract: Transfer RNAs contain various modified nucleotides that are introduced enzymatically at the post-transcriptional level. In Saccharomyces cerevisiae, 3-methylcytidine (m³C) is found at position 32 of the tRNAs for Thr and Ser. We used a systematic reverse genetic approach combined with mass spectrometry (ribonucleome analysis), and identified the actin-binding protein ABP140 as the protein responsible for m³C formation in both tRNA(Thr1) and tRNA(Ser1). ABP140 consists of an N-terminal actin-binding sequence and a C-terminal S-adenosylmethionine (Ado-Met) binding motif. Deletion of the actin-binding sequence in ABP140 did not affect m³C formation, indicating that subcellular localization of ABP140 to actin filaments is not involved in tRNA modification. m³C formation in tRNA(Thr1) could be reconstituted using recombinant Abp140p in the presence of Ado-Met, whereas m³C did not form in tRNA(Ser1) in vitro, indicating the absence of a factor(s) required for tRNA(Ser1) m³C formation. Thus, ABP140 has been designated TRM140 according to the preferred nomenclature. In addition, we observed a specific reduction of m³C formation in HeLa cells by siRNA-mediated knock down of the human ortholog of TRM140.
authors.affiliation: Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Noma
authors.forename: Sanghyun
authors.initials: S
authors.lastname: Yi
authors.forename: Takayuki
authors.initials: T
authors.lastname: Katoh
authors.forename: Yoshimi
authors.initials: Y
authors.lastname: Takai
authors.forename: Takeo
authors.initials: T
authors.lastname: Suzuki
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Suzuki
mesh_terms: D000199:Actins / Q000378:metabolism; D001483:Base Sequence; D001665:Binding Sites; D003562:Cytidine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D008840:Microfilament Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D012343:RNA, Transfer / Q000737:chemistry* / Q000378:metabolism; D012436:S-Adenosylmethionine / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D012359:tRNA Methyltransferases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
chemical_list: C110542:ABP140 protein, S cerevisiae; D000199:Actins; D008840:Microfilament Proteins; D029701:Saccharomyces cerevisiae Proteins; C043208:3-methylcytidine; D003562:Cytidine; D012436:S-Adenosylmethionine; D012343:RNA, Transfer; D012359:tRNA Methyltransferases