The specificities of four yeast dihydrouridine synthases for cytoplasmic tRNAs

J Biol Chem. 2004 Apr 23;279(17):17850-60. doi: 10.1074/jbc.M401221200. Epub 2004 Feb 16.


Dihydrouridine is a highly abundant modified nucleoside found widely in tRNAs of eubacteria, eukaryotes, and some archaea. In cytoplasmic tRNA of Saccharomyces cerevisiae, dihydrouridine occurs exclusively at positions 16, 17, 20, 20A, 20B, and 47. Here we show that the known dihydrouridine synthases Dus1p and Dus2p and two previously uncharacterized homologs, Dus3p (encoded by YLR401c) and Dus4p (YLR405w), are required for all of the dihydrouridine modification of cytoplasmic tRNAs in S. cerevisiae. We have mapped the in vivo position specificity of the four Dus proteins, by three complementary approaches: determination of the molar ratio of dihydrouridine in purified tRNAs from different dus mutants; microarray analysis of a large number of tRNAs based on differential hybridization of uridine and dihydrouridine-containing tRNAs to the complementary oligonucleotides; and the development and use of a novel dihydrouridine mapping technique, employing primer extension. We show that each of the four Dus proteins has a distinct position specificity: Dus1p for U(16) and U(17), Dus2p for U(20), Dus3p for U(47), and Dus4p for U(20a) and U(20b).

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Chromatography, High Pressure Liquid
  • Cytoplasm / metabolism*
  • DNA Primers / chemistry
  • Down-Regulation
  • Models, Chemical
  • Nucleic Acid Hybridization
  • Oligonucleotide Array Sequence Analysis
  • Oxidoreductases / chemistry*
  • RNA / chemistry
  • RNA, Transfer / chemistry
  • RNA, Transfer / metabolism*
  • Saccharomyces cerevisiae / enzymology*
  • Temperature
  • Up-Regulation
  • Uridine / chemistry*


  • DNA Primers
  • RNA
  • RNA, Transfer
  • Oxidoreductases
  • tRNA-dihydrouridine synthase
  • Uridine