Selenocysteine-containing thioredoxin reductase in C. elegans

Vadim N. Gladyshev, Michael Krause, Xue Ming Xu, Konstantin V. Korotkov, Gregory V. Kryukov, Qi An Sun, Byeong Jae Lee, John C. Wootton, Dolph L. Hatfield

Research output: Contribution to journalArticlepeer-review

76 Scopus citations


Mammalian thioredoxin reductases contain a TGA-encoded C-terminal penultimate selenocysteine (Sec) residue, and show little homology to bacterial, yeast, and plant thioredoxin reductases. Here we show that the nematode, Caenorhabditis elegans, contains two homologs related to the mammalian thioredoxin reductase family. The gene for one of these homologs contains a cysteine codon in place of TGA, and its product, designated TR-S, was previously suggested to function as thioredoxin reductase. The other gene contains TGA and its product is designated TR-Se. This Sec-containing thioredoxin reductase lacks a canonical Sec insertion sequence element in the 3'-untranslated area of the gene. TR-Se shows greater sequence similarity to mammalian thioredoxin reductase isozymes TR1 and TR2, whereas TR-S is more similar to TR3. TR-Se was identified as a thioredoxin reductase selenoprotein by labeling C. elegans with 75Se and characterizing the resulting 75Se-labeled protein by affinity and other column chromatography and gel-electrophoresis. TR-Se was expressed in Escherichia coli as a selenoprotein when a bacterial SECIS element was introduced downstream of the Sec TGA codon. The data show that TR-Se is the major naturally occurring selenoprotein in C. elegans, and suggest an important role for selenium and the thioredoxin system in this organism.

Original languageEnglish
Pages (from-to)244-249
Number of pages6
JournalBiochemical and Biophysical Research Communications
Issue number2
StatePublished - Jun 7 1999

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology


Dive into the research topics of 'Selenocysteine-containing thioredoxin reductase in C. elegans'. Together they form a unique fingerprint.

Cite this