SMN1

Survival of motor neuron 1 (SMN1), also known as component of gems 1 or GEMIN1, is a gene that encodes the SMN protein in humans.

Gene

SMN1 is the telomeric copy of the gene encoding the SMN protein; the centromeric copy is termed SMN2. SMN1 and SMN2 are part of a 500 kbp inverted duplication on chromosome 5q13.

This duplicated region contains at least four genes and repetitive elements which make it prone to rearrangements and deletions. The repetitiveness and complexity of the sequence have also caused difficulty in determining the organization of this genomic region. SMN1 and SMN2 are nearly identical and encode the same protein.

The critical sequence difference between the two is a single nucleotide in exon 7 which is thought to be an exon splice enhancer. It is thought that gene conversion events may involve the two genes, leading to varying copy numbers of each gene.

Clinical significance

In 1995, two SMA-related genes, were identified in 5q13 region . The SMN1 gene, located in the telomeric side, is the gene responsible for SMA, its defect causes SMA with different phenotypes, while the SMN2 gene, located in the centromeric side, is a modifier gene for SMA, it is associated with the severity of the disease

Mutations in SMN1 are associated with spinal muscular atrophy.

Mutations in SMN2 alone do not lead to disease, although mutations in both SMN1 and SMN2 result in embryonic death.

Further reading

• Hausmanowa-Petrusewicz I, Jedrzejowska M (2002). "Spinal muscular atrophy of childhood at the edge of the centuries". Functional Neurology. 16 (4 Suppl): 247–53. PMID 11996521.
• Paushkin S, Gubitz AK, Massenet S, Dreyfuss G (June 2002). "The SMN complex, an assemblyosome of ribonucleoproteins". Current Opinion in Cell Biology. 14 (3): 305–12. doi:10.1016/S0955-0674(02)00332-0. PMID 12067652.
• van der Steege G, Draaijers TG, Grootscholten PM, Osinga J, Anzevino R, Velonà I, Den Dunnen JT, Scheffer H, Brahe C, van Ommen GJ (1995). "A provisional transcript map of the spinal muscular atrophy (SMA) critical region". European Journal of Human Genetics. 3 (2): 87–95. doi:10.1159/000472281. PMID 7552146. S2CID 46083524.
• Bussaglia E, Clermont O, Tizzano E, Lefebvre S, Bürglen L, Cruaud C, Urtizberea JA, Colomer J, Munnich A, Baiget M (November 1995). "A frame-shift deletion in the survival motor neuron gene in Spanish spinal muscular atrophy patients". Nature Genetics. 11 (3): 335–7. doi:10.1038/ng1195-335. PMID 7581461. S2CID 10588736.
• Gennarelli M, Lucarelli M, Capon F, Pizzuti A, Merlini L, Angelini C, Novelli G, Dallapiccola B (August 1995). "Survival motor neuron gene transcript analysis in muscles from spinal muscular atrophy patients". Biochemical and Biophysical Research Communications. 213 (1): 342–8. doi:10.1006/bbrc.1995.2135. PMID 7639755.
• Liu Q, Dreyfuss G (July 1996). "A novel nuclear structure containing the survival of motor neurons protein". The EMBO Journal. 15 (14): 3555–65. doi:10.1002/j.1460-2075.1996.tb00725.x. PMC 451956. PMID 8670859.
• van der Steege G, Grootscholten PM, Cobben JM, Zappata S, Scheffer H, den Dunnen JT, van Ommen GJ, Brahe C, Buys CH (October 1996). "Apparent gene conversions involving the SMN gene in the region of the spinal muscular atrophy locus on chromosome 5". American Journal of Human Genetics. 59 (4): 834–8. PMC 1914786. PMID 8808598.
• Bürglen L, Lefebvre S, Clermont O, Burlet P, Viollet L, Cruaud C, Munnich A, Melki J (March 1996). "Structure and organization of the human survival motor neurone (SMN) gene". Genomics. 32 (3): 479–82. doi:10.1006/geno.1996.0147. PMID 8838816.
• Parsons DW, McAndrew PE, Monani UR, Mendell JR, Burghes AH, Prior TW (November 1996). "An 11 base pair duplication in exon 6 of the SMN gene produces a type I spinal muscular atrophy (SMA) phenotype: further evidence for SMN as the primary SMA-determining gene". Human Molecular Genetics. 5 (11): 1727–32. doi:10.1093/hmg/5.11.1727. PMID 8922999.
• Talbot K, Ponting CP, Theodosiou AM, Rodrigues NR, Surtees R, Mountford R, Davies KE (March 1997). "Missense mutation clustering in the survival motor neuron gene: a role for a conserved tyrosine and glycine rich region of the protein in RNA metabolism?". Human Molecular Genetics. 6 (3): 497–500. doi:10.1093/hmg/6.3.497. PMID 9147655.
• Hahnen E, Schönling J, Rudnik-Schöneborn S, Raschke H, Zerres K, Wirth B (May 1997). "Missense mutations in exon 6 of the survival motor neuron gene in patients with spinal muscular atrophy (SMA)". Human Molecular Genetics. 6 (5): 821–5. doi:10.1093/hmg/6.5.821. PMID 9158159.
• Coovert DD, Le TT, McAndrew PE, Strasswimmer J, Crawford TO, Mendell JR, Coulson SE, Androphy EJ, Prior TW, Burghes AH (August 1997). "The survival motor neuron protein in spinal muscular atrophy". Human Molecular Genetics. 6 (8): 1205–14. doi:10.1093/hmg/6.8.1205. PMID 9259265.
• Battaglia G, Princivalle A, Forti F, Lizier C, Zeviani M (October 1997). "Expression of the SMN gene, the spinal muscular atrophy determining gene, in the mammalian central nervous system". Human Molecular Genetics. 6 (11): 1961–71. doi:10.1093/hmg/6.11.1961. PMID 9302277.
• Liu Q, Fischer U, Wang F, Dreyfuss G (September 1997). "The spinal muscular atrophy disease gene product, SMN, and its associated protein SIP1 are in a complex with spliceosomal snRNP proteins". Cell. 90 (6): 1013–21. doi:10.1016/S0092-8674(00)80367-0. PMID 9323129.
• Iwahashi H, Eguchi Y, Yasuhara N, Hanafusa T, Matsuzawa Y, Tsujimoto Y (November 1997). "Synergistic anti-apoptotic activity between Bcl-2 and SMN implicated in spinal muscular atrophy". Nature. 390 (6658): 413–7. Bibcode:1997Natur.390..413I. doi:10.1038/37144. PMID 9389483. S2CID 1936633.
• Chen Q, Baird SD, Mahadevan M, Besner-Johnston A, Farahani R, Xuan J, Kang X, Lefebvre C, Ikeda JE, Korneluk RG, MacKenzie AE (February 1998). "Sequence of a 131-kb region of 5q13.1 containing the spinal muscular atrophy candidate genes SMN and NAIP". Genomics. 48 (1): 121–7. doi:10.1006/geno.1997.5141. PMID 9503025.
• Francis JW, Sandrock AW, Bhide PG, Vonsattel JP, Brown RH (May 1998). "Heterogeneity of subcellular localization and electrophoretic mobility of survival motor neuron (SMN) protein in mammalian neural cells and tissues". Proceedings of the National Academy of Sciences of the United States of America. 95 (11): 6492–7. Bibcode:1998PNAS...95.6492F. doi:10.1073/pnas.95.11.6492. PMC 27826. PMID 9600994.
• Gambardella A, Mazzei R, Toscano A, Annesi G, Pasqua A, Annesi F, Quattrone F, Oliveri RL, Valentino P, Bono F, Aguglia U, Zappia M, Vita G, Quattrone A (November 1998). "Spinal muscular atrophy due to an isolated deletion of exon 8 of the telomeric survival motor neuron gene". Annals of Neurology. 44 (5): 836–9. doi:10.1002/ana.410440522. PMID 9818944. S2CID 22595601.
• Parsons DW, McAndrew PE, Iannaccone ST, Mendell JR, Burghes AH, Prior TW (December 1998). "Intragenic telSMN mutations: frequency, distribution, evidence of a founder effect, and modification of the spinal muscular atrophy phenotype by cenSMN copy number". American Journal of Human Genetics. 63 (6): 1712–23. doi:10.1086/302160. PMC 1377643. PMID 9837824.

External links

• Prior TW, Russman BS (2013). Pagon RA, Adam MP, Ardinger HH, Wallace SE, Amemiya A, Bean LJ, Bird TD, Fong CT, Mefford HC, Smith RJ, Stephens K (eds.). "Spinal Muscular Atrophy". GeneReviews [Internet]. PMID 20301526. Archived from the original on 2020-11-27. Retrieved 2024-02-06.

This article incorporates text from the United States National Library of Medicine, which is in the public domain.