An apparent rare-codon effect on the rate of translation of a Neurospora gene.
As the result of two mutually compensating frameshift mutations, three successive codons with third-position A were generated in the Neurospora crassa am (NADP-specific glutamate dehydrogenase: GDH) gene. These codons do not occur at all elsewhere in the gene and only infrequently in other highly expressed Neurospora genes. The double-frameshift strain produces only 25 to 35% of the normal level of GDH, whether measured as enzyme activity or as immunoprecipitable protein, but its level of GDH mRNA is normal. Although the modified enzyme is somewhat more heat-sensitive than the wild-type in vitro, its stability in vivo was found to be indistinguishable from that of the wild-type. It is concluded that the introduction of consecutive rare codons reduces the efficiency of translation of the mRNA. The possible mechanisms of such an effect are discussed.
Kinnaird
J H
JH
Department of Genetics, University of Edinburgh, Scotland.
Burns
P A
PA
Fincham
J R
JR
D000595:Amino Acid Sequence; D001483:Base Sequence; D015152:Blotting, Northern; D003062:Codon; D004271:DNA, Fungal; D004591:Electrophoresis, Polyacrylamide Gel; D016368:Frameshift Mutation; D005969:Glutamate Dehydrogenase / Q000235:genetics* / Q000378:metabolism; D007700:Kinetics; D008969:Molecular Sequence Data; D009492:Neurospora crassa / Q000201:enzymology / Q000235:genetics*; D014176:Protein Biosynthesis
D003062:Codon; D004271:DNA, Fungal; D005969:Glutamate Dehydrogenase