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.[5][6]
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 kb 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.[6] 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.[6]
Clinical significance
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.
Hausmanowa-Petrusewicz I, Jedrzejowska M (2002). "Spinal muscular atrophy of childhood at the edge of the centuries". Functional Neurology. 16 (4 Suppl): 247–53. PMID11996521.
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. PMID12067652.
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. PMID7552146.
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. PMID7581461.
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. PMID7639755.
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. PMID8838816.
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. doi:10.1038/37144. PMID9389483.
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. PMID9503025.
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. PMID9818944.