Mammalian Selenoprotein in Which Selenocysteine (Sec) Incorporation Is Supported by a New Form of Sec Insertion Sequence Element

• DOI: 10.1128/mcb.22.5.1402-1411.2002
• Publication Date: 2002-07-27T09:56:57Z
• Authors: Konstantin V. Kor...; Sergey V. Novoselov; Dolph L. Hatfield; Vadim N. Gladyshev
• Keywords: Selenocysteine; Insertion sequence; Sequence (biology); Selenoprotein; Selenoprotein P

Selenocysteine (Sec), the 21st amino acid in protein, is encoded by UGA. The Sec insertion sequence (SECIS) element, which stem-loop structure present 3′ untranslated regions (UTRs) of eukaryotic selenoprotein-encoding genes, essential for recognition UGA as a codon rather than stop signal. We now report identification new selenoprotein, designated selenoprotein M (SelM). 3-kb human SelM-encoding gene has five exons and located on chromosome 22 but not been correctly identified either Celera or public Human Genome Project. characterized mouse SelM cDNA sequences expressed various mammalian cell lines. 3" UTR human, mouse, rat genes lacks canonical SECIS element. Instead, incorporated response to conserved mRNA structure, cytidines are place adenosines previously considered invariant. Substitution did alter incorporation; however, other mutant structures support synthesis, demonstrating that this form element functional. variety tissues, with increased levels brain. It localized perinuclear structures, its N-terminal signal peptide necessary protein translocation.