Survival of motor neuron protein 2 (SMN2)

Survival of motor neuron protein 2 (SMN2) is a gene residing on chromosome 5q13 that encodes the SMN protein—crucial for motor neuron function. It is nearly identical to SMN1 but contains a sequence variant leading to predominant exon 7 skipping and production of a truncated, unstable protein; only about 10–15% of its transcripts give rise to full-length, functional SMN protein[3][1][5]. The SMN protein is essential for assembly of spliceosomal snRNPs and proper pre-mRNA processing within the SMN complex. In spinal muscular atrophy (SMA), loss of SMN1 causes disease, while the SMN2 gene's residual production of functional protein modifies the severity of symptoms. Therapeutic strategies focus on increasing full-length SMN protein from SMN2 by modulating splicing or upregulating gene expression[2][5][1]. The number of SMN2 gene copies directly correlates with severity of SMA: more SMN2 alleles result in milder disease[1][5]. Note: Some aliases cited (GEMIN1, TDRD16B, Gemin-1) refer to separate proteins involved in the SMN complex; they are not correct designations for SMN2[3]. The canonical gene/protein name is "Survival of motor neuron protein 2" (SMN2).

Other names

Survival motor neuron protein 2SMN2Survival of motor neuron 2Survival motor neuron protein (generic)SMNT (less common)SMNC (historical, less common)Component of gems 1 (functional complex member)Gemin-1 (distinct protein, alias sometimes applied incorrectly)tudor domain containing 16B (historically, but now assigned to TDRD16B)BCD541 (nonstandard, sometimes appears in databases)C-BCD541 (rare; not standardized)GEMIN1/TDRD16B/Gemin-1 (historical mix-up, not correct aliases for SMN2)

Increasing exon 7 inclusion by splicing modulation (antisense oligonucleotides, small molecules); Upregulation of SMN2 gene expression (epigenetic drugs like HDAC inhibitors); Stabilization of SMN2 mRNA