Cloning and expression of a mammalian peptide chain release factor with sequence similarity to tryptophanyl-tRNA synthetases.
The termination of protein synthesis is encoded by in-frame nonsense (stop) codons. Most organisms use three nonsense codons: UGA, UAG, and UAA. In contrast to sense codons, which are decoded by specific tRNAs, nonsense codons are decoded by proteins called release factors (RFs). Here we report the cloning of a mammalian RF cDNA by the use of monoclonal antibodies specific for rabbit RF. Functional studies showed that, when expressed in Escherichia coli, the protein encoded by this cDNA has in vitro biochemical characteristics similar to those of previously characterized mammalian RFs. DNA sequencing of this eukaryotic RF cDNA revealed a remarkable sequence similarity to bacterial and mitochondrial tryptophanyl-tRNA synthetases, with the greatest similarity confined to the synthetase active site, and no obvious similarity to bacterial RFs.
Institute for Molecular Genetics, Baylor College of Medicine, Houston, TX 77030.
C C
CC
Lee
W J
WJ
Craigen
D M
DM
Muzny
E
E
Harlow
C T
CT
Caskey
D000595:Amino Acid Sequence; D000604:Amino Acyl-tRNA Synthetases / Q000235:genetics*; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002460:Cell Line; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D015723:Gene Library; D008099:Liver / Q000378:metabolism; D008969:Molecular Sequence Data; D010454:Peptide Termination Factors / Q000235:genetics*; D011817:Rabbits; D012689:Sequence Homology, Nucleic Acid; D014162:Transfection; D014369:Tryptophan-tRNA Ligase / Q000235:genetics*
D010454:Peptide Termination Factors; C070289:peptide chain release factor, mammalian; D004247:DNA; D000604:Amino Acyl-tRNA Synthetases; D014369:Tryptophan-tRNA Ligase