Mak21p of Saccharomyces cerevisiae, a homolog of human CAATT-binding protein, is essential for 60 S ribosomal subunit biogenesis.
Mak21-1 mutants are unable to propagate M1 double-stranded RNA, a satellite of the L-A double-stranded RNA virus, encoding a secreted protein toxin lethal to yeast strains that do not carry M1. We cloned MAK21 using its map location and found that Mak21p is homologous to a human and mouse CAATT-binding protein and open reading frames in Schizosaccharomyces pombe and Caenorhabditis elegans. Although the human protein regulates Hsp70 production, Mak21p is essential for growth and necessary for 60 S ribosomal subunit biogenesis. mak21-1 mutants have decreased levels of L-A coat protein and L-A double-stranded RNA. Electroporation with reporter mRNAs shows that mak21-1 cells cannot optimally express mRNAs which, like L-A viral mRNA, lack 3'-poly(A) or 5'-cap structures but can normally express mRNA with both cap and poly(A). The virus propagation phenotype of mak21-1 is suppressed by ski2 or ski6 mutations, each of which derepresses translation of non-poly(A) mRNA.
Edskes
H K
HK
Laboratory of Biochemistry and Genetics, NIDDK, National Institutes of Health, Bethesda, Maryland 20892-0830, USA.
Ohtake
Y
Y
Wickner
R B
RB
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins; D016366:Open Reading Frames; D012270:Ribosomes / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D004268:DNA-Binding Proteins; C115485:MAK21 protein, S cerevisiae; D009363:Neoplasm Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors