A new yeast translation initiation factor suppresses a mutation in the eIF-4A RNA helicase.
We have isolated a gene, STM1, which encodes a new translation initiation factor from Saccharomyces cerevisiae. The gene acts, if present on a multicopy plasmid, as a suppressor of a temperature-sensitive mutation in eIF-4A. The single copy STM1 gene is not essential, but disruption causes a slow growth phenotype. Analysis of polysomes from a strain carrying a disrupted stm1 allele shows a clear defect in translation initiation as shown by a strong reduction in polysomes and an increase in the monosomes. Sequence analysis revealed interesting features of the putative Stm1 protein. Comparison of the entire protein sequence with databanks showed some similarity with the human eIF-4B protein. The Stm1 protein has potential RNP1 and RNP2 motifs characteristic for RNA-binding proteins. The protein also contains six highly conserved direct repeats of 21-26 amino acids and one partial repeat.
Coppolecchia
R
R
Department of Microbiology, University of Basel, Switzerland.
Buser
P
P
Stotz
A
A
Linder
P
P
D000595:Amino Acid Sequence; D001483:Base Sequence; D015152:Blotting, Northern; D004271:DNA, Fungal; D039601:Eukaryotic Initiation Factor-4A; D039642:Eukaryotic Initiation Factors; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D005800:Genes, Fungal; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D010448:Peptide Initiation Factors / Q000235:genetics* / Q000378:metabolism; D010641:Phenotype; D010957:Plasmids; D014176:Protein Biosynthesis; D020365:RNA Helicases; D012316:RNA Nucleotidyltransferases / Q000235:genetics* / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid; D013489:Suppression, Genetic; D013696:Temperature
D004271:DNA, Fungal; D039642:Eukaryotic Initiation Factors; D005656:Fungal Proteins; D010448:Peptide Initiation Factors; D029701:Saccharomyces cerevisiae Proteins; C083432:TIF3 protein, S cerevisiae; D039601:Eukaryotic Initiation Factor-4A; D012316:RNA Nucleotidyltransferases; D020365:RNA Helicases