       Document 0407
 DOCN  M9640407
 TI    RNA-binding proteins that specifically recognize the selenocysteine
       insertion sequence of human cellular glutathione peroxidase mRNA.
 DT    9604
 AU    Shen Q; McQuilkin PA; Newburger PE; Department of Pediatrics, University
       of Massachusetts Medical; School, Worcester 01655, USA.
 SO    J Biol Chem. 1995 Dec 22;270(51):30448-52. Unique Identifier : AIDSLINE
       MED/96107197
 AB    Translational incorporation of the unusual amino acid selenocysteine in
       eukaryotes requires a coding region UGA codon (which otherwise serves as
       a termination signal), a selenocysteine insertion sequence (SECIS) in
       the 3'-untranslated region of the mRNA, and selenocysteyl-tRNA. The
       mechanisms involved in SECIS recognition by the eukaryotic translational
       machinery remain unknown. We report the detection of RNA-binding
       proteins that specifically recognize the SECIS from human cellular
       glutathione peroxidase (GPX1) transcripts. RNA gel shift assays showed
       three retarded bands after incubation with COS-1 whole cell lysate or
       S-100 cytosol fraction or with extracts from hepatoma cell lines HepG2
       and Hep3B. The specificity of the binding was demonstrated by
       competition by cold unlabeled SECIS RNA and by lack of competition by
       other RNA species with similar stem-loop secondary structures, such as
       the human immunodeficiency virus (HIV) transactivation-response region
       of HIV mRNA element, and mutated SECIS constructs. UV cross-linking and
       SDS-polyacrylamide gel electrophoresis revealed at least two proteins,
       with estimated molecular masses of 55,000 and 65,000 Da, that bind to
       the SECIS. Examination of a series of insertion and deletion SECIS
       mutants indicated recognition of the SECIS primarily through the basal
       stem region, although the upper stem, loop, and two of three short
       conserved sequences also appear to contribute to the affinity of the
       binding.
 DE    Base Sequence  Binding Sites  Cloning, Molecular  Comparative Study  DNA
       Primers  Glutathione Peroxidase/*BIOSYNTHESIS  Human  HIV/METABOLISM
       Molecular Sequence Data  Mutagenesis, Insertional  Nucleic Acid
       Conformation  Polymerase Chain Reaction  Recombinant
       Proteins/BIOSYNTHESIS  RNA-Binding Proteins/*METABOLISM  RNA,
       Messenger/CHEMISTRY/*METABOLISM  RNA, Viral/CHEMISTRY/METABOLISM
       Selenocysteine/*METABOLISM  Structure-Activity Relationship  Substrate
       Specificity  Support, Non-U.S. Gov't  Support, U.S. Gov't, P.H.S.
       JOURNAL ARTICLE

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).

