SMN1

Survival motor neuron protein also known as component of gems 1 or gemin-1 is a is_associated_with::protein that in humans is encoded by the SMN1 is_associated_with::gene. Two transcript variants are produced by this gene.

Gene
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.

Clinical significance
Mutations in the telomeric copy of this gene are associated with is_associated_with::spinal muscular atrophy; mutations in the is_associated_with::centromeric copy do not lead to disease. The centromeric copy 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. It is thought that gene conversion events may involve the two genes, leading to varying copy numbers of each gene.

Function
The protein encoded by this gene contains Gemin2-binding, Tudor and YG-Box domains. It 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 is_associated_with::ribonucleoproteins (snRNPs). This protein forms heteromeric complexes with proteins such as is_associated_with::SIP1 and is_associated_with::GEMIN4, and also interacts with several proteins known to be involved in the is_associated_with::biogenesis of snRNPs, such as hnRNP U protein and the small nucleolar RNA binding protein.

Interactions
SMN1 has been shown to interact with:


 * is_associated_with::Bcl-2,
 * is_associated_with::Coilin,
 * is_associated_with::DDX20,
 * is_associated_with::DHX9,
 * FBL,
 * FUBP1,
 * GAR1,
 * GEMIN2,
 * is_associated_with::GEMIN4,
 * is_associated_with::GEMIN5,
 * GEMIN7,
 * is_associated_with::HNRNPR,
 * is_associated_with::KPNB1,
 * is_associated_with::P53,
 * SNRPD1,  and
 * SNRPD2.