Analysis of smu-1, a gene that regulates the alternative splicing of unc-52 pre-mRNA in Caenorhabditis elegans.
Mutations in the smu-1 gene of Caenorhabditis elegans were previously shown to suppress mutations in the genes mec-8 and unc-52. mec-8 encodes a putative RNA binding protein that affects the accumulation of specific alternatively spliced mRNA isoforms produced by unc-52 and other genes. unc-52 encodes a set of basement membrane proteins, homologs of mammalian perlecan, that are important for body wall muscle assembly and attachment to basement membrane, hypodermis, and cuticle. We show that a presumptive null mutation in smu-1 suppresses nonsense mutations in exon 17 but not exon 18 of unc-52 and enhances the phenotype conferred by an unc-52 splice site mutation in intron 16. We have used reverse transcription-PCR and RNase protection to show that loss-of-function smu-1 mutations enhance accumulation in larvae of an alternatively spliced isoform that skips exon 17 but not exon 18 of unc-52. We have identified smu-1 molecularly; it encodes a nuclearly localized protein that contains five WD motifs and is ubiquitously expressed. The SMU-1 amino acid sequence is more than 60% identical to a predicted human protein of unknown function. We propose that smu-1 encodes a trans-acting factor that regulates the alternative splicing of the pre-mRNA of unc-52 and other genes.
Spike
C A
CA
Department of Genetics, Cell Biology, and Development, University of Minnesota, St. Paul, Minnesota 55108, USA.
Shaw
J E
JE
Herman
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RK
D017398:Alternative Splicing; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D017173:Caenorhabditis elegans / Q000196:embryology / Q000378:metabolism*; D029742:Caenorhabditis elegans Proteins; D002467:Cell Nucleus / Q000378:metabolism; D003001:Cloning, Molecular; D018389:Codon, Nonsense; D005091:Exons; D015801:Helminth Proteins / Q000235:genetics*; D008565:Membrane Proteins; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics*; D010641:Phenotype; D020161:Physical Chromosome Mapping; D011509:Proteoglycans / Q000235:genetics*; D012326:RNA Splicing; D012333:RNA, Messenger / Q000378:metabolism*; D011993:Recombinant Fusion Proteins; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012260:Ribonucleases / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013489:Suppression, Genetic; D015533:Transcriptional Activation; D019076:Transgenes
D029742:Caenorhabditis elegans Proteins; D018389:Codon, Nonsense; D015801:Helminth Proteins; D008565:Membrane Proteins; D009687:Nuclear Proteins; D011509:Proteoglycans; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; C432686:Smu-1 protein, C elegans; C082396:unc-52 protein, C elegans; D012260:Ribonucleases