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Hypomutability at the Polyadenine Tract in SMN Intron 3 Shows the Invariability of the a‐SMN Protein Structure
Author(s) -
Sasongko T. H.,
Yusoff S.,
Lee M. J.,
Nishioka E.,
Matsuo M.,
Nishio H.
Publication year - 2008
Publication title -
annals of human genetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.537
H-Index - 77
eISSN - 1469-1809
pISSN - 0003-4800
DOI - 10.1111/j.1469-1809.2007.00409.x
Subject(s) - spinal muscular atrophy , intron , sma* , biology , genetics , open reading frame , gene , mutation , peptide sequence , mathematics , combinatorics
Summary Recently, the axonal‐SMN (a‐SMN) protein, which is generated by the gene responsible for spinal muscular atrophy (SMA), SMN , has been reported. Surprisingly, the a‐SMN transcript includes the entire sequence of SMN intron 3. We had expected a high frequency of insertion/deletion mutations at a polyadenine tract in this intron, since simple repetitive sequence motifs are prone to mutations. Such mutations could change the C‐terminal structure of the a‐SMN protein. However, our study showed that almost all individuals, including healthy individuals, SMA patients and SMA‐like patients, carried only alleles with a normal polyadenine tract. Hypomutability of the polyadenine tract in SMN intron 3 suggests the existence of transcriptional mechanisms preventing alterations to the open reading frame of axonal SMN and not allowing variability in the protein structure of a‐SMN.