An enhancer screen identifies a gene that encodes the yeast U1 snRNP A protein: implications for snRNP protein function in pre-mRNA splicing.
In an enhancer screen for yeast mutants that may interact with U1 small nuclear RNA (snRNA), we identified a gene that encodes the apparent yeast homolog of the well-studied human U1A protein. Both in vitro and in vivo, the absence of the protein has a dramatic effect on the activity of U1 snRNP containing the mutant U1 snRNA used in the screen. Surprisingly, the U1A gene is inessential in a wild-type U1 RNA background, as growth rate and the splicing of endogenous pre-mRNA transcripts are normal in these strains that lack the U1A protein. Even in vitro, the absence of the protein has little effect on splicing. On the basis of these observations, we suggest that a principal role of the U1A protein is to help fold or maintain U1 RNA in an active configuration.
Liao
X C
XC
Howard Hughes Medical Institute, Department of Biology, Brandeis University, Waltham, Massachusetts 02254.
Tang
J
J
Rosbash
M
M
D000483:Alleles; D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics; D005800:Genes, Fungal; D006801:Humans; D008957:Models, Genetic; D008961:Models, Structural; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D009690:Nucleic Acid Conformation; D009838:Oligodeoxyribonucleotides; D016366:Open Reading Frames; D016133:Polymerase Chain Reaction / Q000379:methods; D017433:Protein Structure, Secondary; D012322:RNA Precursors / Q000235:genetics* / Q000378:metabolism; D012326:RNA Splicing; D012342:RNA, Small Nuclear / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D015183:Restriction Mapping; D017412:Ribonucleoprotein, U1 Small Nuclear / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D017386:Sequence Homology, Amino Acid
D009838:Oligodeoxyribonucleotides; D012322:RNA Precursors; D012342:RNA, Small Nuclear; D017412:Ribonucleoprotein, U1 Small Nuclear