TY - JOUR
T1 - The 3′-untranslated region of human type 2 lodothyronine deiodinase mRNA contains a functional selenocysteine insertion sequence element
AU - Buettner, Christoph
AU - Harney, John W.
AU - Reed Larsen, P.
PY - 1998/12/11
Y1 - 1998/12/11
N2 - Type 2 deiodinase (D2) catalyzes the 5′-deiodination of thyroxine to form 3,5,3′-triiodothyronine. Two mammalian D2 cDNAs have been identified containing 2 kilobases (kb) of the 7-kb mRNA including the complete coding sequence. Both contain in-frame TGA codons, which should serve as selenocysteine codons. However, the selenocysteine insertion sequence (SECIS) elements required for the decoding of UGA as a selenocysteine in the 3′-untranslated region (UTR) of the mRNA are not present. We have identified two overlapping expressed sequence tag clones, which contain the missing 4.4-kb 3′-UTR of the human D2 (hD2) cDNA. Computer analysis predicts a stem loop structure 280 base pairs 5′ to the polyadenylation site, which has potent SECIS activity. A fragment containing these sequences hybridizes to D2 mRNA in human thyroid. A G to A mutation in the essential AUGA motif of this element abolished its function. Transfection of the hD2 coding region plus the 3'-UTR results in the expression of D2, and its in vitro transcribed mRNA programs D2 activity in Xenopus oocytes. This is the first identification of a SECIS element in a mammalian D2 cDNA and establishes that hD2 is a bona fide selenoprotein.
AB - Type 2 deiodinase (D2) catalyzes the 5′-deiodination of thyroxine to form 3,5,3′-triiodothyronine. Two mammalian D2 cDNAs have been identified containing 2 kilobases (kb) of the 7-kb mRNA including the complete coding sequence. Both contain in-frame TGA codons, which should serve as selenocysteine codons. However, the selenocysteine insertion sequence (SECIS) elements required for the decoding of UGA as a selenocysteine in the 3′-untranslated region (UTR) of the mRNA are not present. We have identified two overlapping expressed sequence tag clones, which contain the missing 4.4-kb 3′-UTR of the human D2 (hD2) cDNA. Computer analysis predicts a stem loop structure 280 base pairs 5′ to the polyadenylation site, which has potent SECIS activity. A fragment containing these sequences hybridizes to D2 mRNA in human thyroid. A G to A mutation in the essential AUGA motif of this element abolished its function. Transfection of the hD2 coding region plus the 3'-UTR results in the expression of D2, and its in vitro transcribed mRNA programs D2 activity in Xenopus oocytes. This is the first identification of a SECIS element in a mammalian D2 cDNA and establishes that hD2 is a bona fide selenoprotein.
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U2 - https://doi.org/10.1074/jbc.273.50.33374
DO - https://doi.org/10.1074/jbc.273.50.33374
M3 - Article
C2 - 9837913
SN - 0021-9258
VL - 273
SP - 33374
EP - 33378
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 50
ER -