Title

Identification and molecular cloning of a human selenocysteine insertion sequence-binding protein. A bifunctional role for DNA-binding protein B

UMMS Affiliation

Department of Pediatrics; Department of Physiology

Date

4-16-1998

Document Type

Article

Subjects

Amino Acid Sequence; Animals; *CCAAT-Enhancer-Binding Proteins; Cell Line; Cloning, Molecular; DNA-Binding Proteins; Gene Products, tat; Glutathione Peroxidase; Humans; Iodide Peroxidase; Molecular Sequence Data; NFI Transcription Factors; Nuclear Proteins; Protein Biosynthesis; *Proteins; RNA-Binding Proteins; Recombinant Proteins; Selenocysteine; Selenoproteins; Sequence Analysis; Sequence Analysis, DNA; Sequence Homology, Amino Acid; *Transcription Factors; Y-Box-Binding Protein 1

Disciplines

Life Sciences | Medicine and Health Sciences

Abstract

Prokaryotic and eukaryotic cells incorporate the unusual amino acid selenocysteine at a UGA codon, which conventionally serves as a termination signal. Translation of eukaryotic selenoprotein mRNA requires a nucleotide selenocysteine insertion sequence in the 3'-untranslated region. We report the molecular cloning of the binding protein that recognizes the selenocysteine insertion sequence element in human cellular glutathione peroxidase gene (GPX1) transcripts and its identification as DNA-binding protein B, a member of the EFIA/dbpB/YB-1 family. The predicted amino acid sequence contains four arginine-rich RNA-binding motifs, and one segment shows strong homology to the human immunodeficiency virus Tat domain. Recombinant DNA-binding protein B binds the selenocysteine insertion sequence elements from the GPX1 and type I iodothyronine 5'-deiodinase genes in RNA electrophoretic mobility shift assays and competes with endogenous GPX1 selenocysteine insertion sequence binding activity in COS-1 cytosol extracts. Addition of antibody to DNA-binding protein B to COS-1 electromobility shift assays produces a slowly migrating "supershift" band. The molecular cloning and identification of DNA-binding protein B as the first eukaryotic selenocysteine insertion sequence-binding protein opens the way to the elucidation of the entire complex necessary for the alternative reading of the genetic code that permits translation of selenoproteins.

Rights and Permissions

Citation: J Biol Chem. 1998 Mar 6;273(10):5443-6.

Related Resources

Link to Article in PubMed

Journal Title

The Journal of biological chemistry

PubMed ID

9488664