The sigma(70)-like motif: a eukaryotic RNA binding domain unique to a superfamily of proteins required for ribosome biogenesis.
Little is understood about the role of nucleolar RNA binding proteins in ribosome biogenesis, although there is a clear need for them based on the strict folding requirements of the pre-rRNA. We have identified a superfamily of RNA binding proteins whose members are required for different stages of ribosome biogenesis. The Imp4 superfamily is composed of five individual families (Imp4, Rpf1, Rpf2, Brx1, and Ssf) that all possess the sigma(70)-like motif, a eukaryotic RNA binding domain with prokaryotic origins. The Imp4 superfamily members associate with RNAs that are consistent with their distinct roles in ribosome biogenesis and suggest the mechanisms by which they function.
Wehner
Karen A
KA
Yale University School of Medicine, Department of Genetics, New Haven, CT 06520, USA.
Baserga
Susan J
SJ
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001665:Binding Sites; D002466:Cell Nucleolus / Q000378:metabolism; D012321:DNA-Directed RNA Polymerases / Q000737:chemistry / Q000502:physiology*; D005057:Eukaryotic Cells / Q000378:metabolism*; D008954:Models, Biological; D008969:Molecular Sequence Data; D005810:Multigene Family; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology; D010802:Phylogeny; D011485:Protein Binding; D012313:RNA / Q000378:metabolism; D012335:RNA, Ribosomal / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D020718:Ribonucleoproteins, Small Nucleolar / Q000737:chemistry; D012269:Ribosomal Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology; D012270:Ribosomes / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012808:Sigma Factor / Q000737:chemistry / Q000502:physiology*; D013329:Structure-Activity Relationship
C451024:BRX1 protein, S cerevisiae; C120534:IMP4 protein, S cerevisiae; D009687:Nuclear Proteins; D012335:RNA, Ribosomal; D016601:RNA-Binding Proteins; C451023:RPF2 protein, S cerevisiae; D020718:Ribonucleoproteins, Small Nucleolar; D012269:Ribosomal Proteins; C451022:Rpf1 protein, S cerevisiae; C114037:SSF1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D012808:Sigma Factor; C117377:ribonucleoprotein, U3 small nucleolar; D012313:RNA; C081775:RNA polymerase sigma 70; D012321:DNA-Directed RNA Polymerases