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Survival of motor neuron 2, centromeric
PDB 1g5v EBI.jpg
PDB rendering based on 1g5v.
Available structures
PDB Ortholog search: PDBe, RCSB
Symbols SMN2 ; BCD541; C-BCD541; GEMIN1; SMNC; TDRD16B
External IDs OMIM601627 MGI109257 HomoloGene292 GeneCards: SMN2 Gene
Species Human Mouse
Entrez 6607 20595
Ensembl ENSG00000172062 ENSMUSG00000021645
UniProt Q16637 P97801
RefSeq (mRNA) NM_017411 NM_001252629
RefSeq (protein) NP_059107 NP_001239558
Location (UCSC) Chr 5:
69.35 – 69.37 Mb
Chr 13:
100.12 – 100.14 Mb
PubMed search [1] [2]

Survival of motor neuron 2, centromeric also known as SMN2 is a protein which in humans is encoded by the SMN2 gene.[1][2]


This gene is 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. The telomeric and centromeric copies of this gene are nearly identical and encode the same protein. While mutations in the telomeric copy are associated with spinal muscular atrophy, mutations in this gene, the centromeric copy, do not lead to disease. This gene may be a modifier of disease caused by mutation in the telomeric copy. The critical sequence difference between the two genes is a single nucleotide in exon 7, which is thought to be an exon splice enhancer. Note that the nine exons of both the telomeric and centromeric copies are designated historically as exon 1, 2a, 2b, and 3-8. It is thought that gene conversion events may involve the two genes, leading to varying copy numbers of each gene.[2]


The full length protein encoded by this gene localizes to both the cytoplasm and the nucleus. Within the nucleus, the protein localizes to subnuclear bodies called gems which are found near coiled bodies containing high concentrations of small ribonucleoproteins (snRNPs). This protein forms heteromeric complexes with proteins such as SIP1 and GEMIN4, and also interacts with several proteins known to be involved in the biogenesis of snRNPs, such as hnRNP U protein and the small nucleolar RNA binding protein. Four transcript variants encoding distinct isoforms have been described.[2]

See also[edit]


  1. ^ Lefebvre S, Bürglen L, Reboullet S, Clermont O, Burlet P, Viollet L, Benichou B, Cruaud C, Millasseau P, Zeviani M (January 1995). "Identification and characterization of a spinal muscular atrophy-determining gene". Cell 80 (1): 155–65. doi:10.1016/0092-8674(95)90460-3. PMID 7813012. 
  2. ^ a b c "Entrez Gene: survival of motor neuron 2, centromeric". 

Further reading[edit]

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