Heterologous expression of archaeal selenoprotein genes directed by the SECIS element located in the 3' non-translated region.
Previous in silico analysis of selenoprotein genes in Archaea revealed that the selenocysteine insertion (SECIS) motif necessary to recode UGA with selenocysteine was not adjacent to the UGA codon as is found in Bacteria. Rather, paralogous stem-loop structures are located in the 3' untranslated region (3' UTR), reminiscent of the situation in Eukarya. To assess the function of such putative SECIS elements, the Methanococcus jannaschii MJ0029 (fruA, which encodes the A subunit of the coenzyme F420-reducing hydrogenase) mRNA was mapped in vivo and probed enzymatically in vitro. It was shown that the SECIS element is indeed transcribed as part of the respective mRNA and that its secondary structure corresponds to that predicted by RNA folding programs. Its ability to direct selenocysteine insertion in vivo was demonstrated by the heterologous expression of MJ0029 in Methanococcus maripaludis, resulting in the synthesis of an additional selenoprotein, as analysed by 75Se labelling. The selective advantage of moving the SECIS element in the untranslated region may confer the ability to insert more than one selenocysteine into a single polypeptide. Evidence for this assumption was provided by the finding that the M. maripaludis genome contains an open reading frame with two in frame TGA codons, followed by a stem-loop structure in the 3' UTR of the mRNA that corresponds to the archaeal SECIS element.
Rother
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Lehrstuhl für Mikrobiologie der Universität München, Maria-Ward-Strasse 1a, D-80638 München, Germany.
Resch
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A
Gardner
W L
WL
Whitman
W B
WB
Böck
A
A
D020413:3' Untranslated Regions; D000595:Amino Acid Sequence; D019843:Archaeal Proteins / Q000235:genetics* / Q000378:metabolism; D001426:Bacterial Proteins; D001483:Base Sequence; D004251:DNA Transposable Elements; D019848:Gene Expression Regulation, Archaeal; D017017:Methanococcus / Q000235:genetics*; D008969:Molecular Sequence Data; D011506:Proteins / Q000235:genetics* / Q000378:metabolism; D017279:Selenocysteine / Q000378:metabolism; D051140:Selenoproteins; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000235:genetics
D020413:3' Untranslated Regions; D019843:Archaeal Proteins; D001426:Bacterial Proteins; D004251:DNA Transposable Elements; C104848:FruA protein, Myxococcus xanthus; D011506:Proteins; D051140:Selenoproteins; D014157:Transcription Factors; C432140:VhuD protein, Methanococcus maripaludis; D017279:Selenocysteine