HGNC Approved Gene Symbol: SMTN
Cytogenetic location: 22q12.2 Genomic coordinates (GRCh38): 22:31,064,118-31,104,624 (from NCBI)
Van der Loop et al. (1996) used expression cloning to isolate a novel gene whose expression is restricted to smooth muscle cells. This gene, termed smoothelin (SMTN), encodes a 371-amino acid polypeptide. Sequence analysis revealed that the protein contains a 56-amino acid domain with significant homology to a sequence that flanks the actin-binding domains of dystrophin, utrophin, beta-spectrin, and alpha-actinin. Cell fractionation studies suggested to the authors that smoothelin is a part of the cytoskeleton. By Northern blot analysis, van der Loop et al. (1996) showed that the gene is expressed as a 1.5-kb mRNA in several tissues containing smooth muscle, but not in brain, adipose tissue, cardiac muscle, or skeletal muscle. Transfection of the human cDNA into smooth muscle cells or COS-7 cells produced a 59-kD protein that assembled into a filamentous network. Subcellular localization showed that smoothelin is associated with stress fibers. Van der Loop et al. (1996) found that smoothelin is not detected in primary or long-term smooth muscle cell cultures. They also found that transcription of smoothelin is halted in smooth muscle explants.
Engelen et al. (1997) used fluorescence in situ hybridization and radiation hybrid mapping to localize the SMTN gene to human chromosome 22q12.3. They reported that the SMTN locus is approximately 1.3 Mb from the marker D22S273, distal to the loci TUPLE1 (600237) and D22S75. This mapping places the SMTN locus outside of the deletion associated with DiGeorge syndrome (188400).
By FISH, Rensen et al. (2000) mapped the mouse Smtn gene to chromosome 11A2-A3.
Engelen, J. J. M., Esterling, L. E., Albrechts, J. C. M., Detera-Wadleigh, S. D., van Eys, G. J. J. M. Assignment of the human gene for smoothelin (SMTN) to chromosome 22q12 by fluorescence in situ hybridization and radiation hybrid mapping. Genomics 43: 245-247, 1997. [PubMed: 9244445] [Full Text: https://doi.org/10.1006/geno.1997.9999]
Rensen, S., Merkx, G., Doevendans, P., Geurts van Kessel, A., van Eys, G. Structure and chromosome location of Smtn, the mouse smoothelin gene. Cytogenet. Cell Genet. 89: 225-229, 2000. [PubMed: 10965129] [Full Text: https://doi.org/10.1159/000015619]
van der Loop, F. T. L., Schaart, G., Timmer, E. D. J., Ramaekers, F. C. S., van Eys, G. J. J. M. Smoothelin, a novel cytoskeletal protein specific for smooth muscle cells. J. Cell Biol. 134: 401-411, 1996. [PubMed: 8707825] [Full Text: https://doi.org/10.1083/jcb.134.2.401]