SMA-3 smad has specific and critical functions in DBL-1/SMA-6 TGFbeta-related signaling.
A TGFbeta signal transduction cascade controls body size and male tail morphogenesis in the nematode Caenorhabditis elegans. We have analyzed the function of the sma-3 Smad gene, one of three Smad genes that function in this pathway. Null mutations in sma-3 are at least as severe as null mutations in the ligand and type I receptor genes, dbl-1 and sma-6, indicating that the other Smads do not function in the absence of SMA-3. Furthermore, null mutations in sma-3 do not cause defects in egg laying or in regulation of the developmentally arrested dauer larva stage, indicating no overlapping function with another C. elegans TGFbeta signaling pathway. The sma-3 gene is widely expressed at all developmental stages in hermaphrodites and males. The molecular lesions associated with eight sma-3 alleles of varying severity have been determined. The missense mutations cluster in two previously identified regions important for Smad function.
Savage-Dunn
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Department of Biology, City University of New York, Flushing, New York 11367, USA.
Tokarz
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Wang
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Cohen
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S
Giannikas
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Padgett
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RW
D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D030801:Animals, Genetically Modified; D019485:Bone Morphogenetic Proteins / Q000378:metabolism; D017173:Caenorhabditis elegans / Q000196:embryology / Q000235:genetics; D029742:Caenorhabditis elegans Proteins; D015801:Helminth Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D008024:Ligands; D008297:Male; D008969:Molecular Sequence Data; D020125:Mutation, Missense; D009479:Neuropeptides / Q000378:metabolism*; D010641:Phenotype; D011956:Receptors, Cell Surface / Q000378:metabolism*; D015398:Signal Transduction; D013623:Tail / Q000196:embryology; D013997:Time Factors; D016212:Transforming Growth Factor beta / Q000378:metabolism*
D019485:Bone Morphogenetic Proteins; D029742:Caenorhabditis elegans Proteins; C117509:Dbl-1 protein, C elegans; D015801:Helminth Proteins; D008024:Ligands; D009479:Neuropeptides; D011956:Receptors, Cell Surface; C117510:SMA-6 protein, C elegans; D016212:Transforming Growth Factor beta; C097874:sma-3 protein, C elegans