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Genetic polymorphism and sequence evolut ... llary acidic protein gene, GFAP
Genetic polymorphism and sequence evolution of an alternatively spliced exon of the glial fibrillary acidic protein gene, GFAP
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Isoform GFAPepsilon of the human cytoskeletal protein GFAP carries, as the result of alternative splicing of exon 7a of GFAP, a novel 42-amino-acid-long C-terminal region with binding capacity for the presenilin proteins. Here we show that exon 7a is present in a variety of mammals but absent from GFAP of chicken and fish. Comparison of the mouse and human GFAP exons showed an increased rate of nonsynonymous nucleotide substitutions in exon 7a compared to the other exons. This resulted in 10 nonconservative and 2 conservative amino acid substitutions and suggests that exon 7a has evolved under different functional constraints. Exons 7a of humans and higher primates are 100% identical apart from alanine codon 426, which is conserved in only 9% of the human alleles, while 21 and 70% of the alleles, respectively, have a valine or a threonine codon at that position. Threonine represents a potential phosphorylation site, and positive selection of that effect could explain the high allele frequency.
Singh R, Nielsen AL, Johansen MG, Jørgensen AL
Genomics
2003-08-01 00:00
82
2
185-93
Alternative Splicing,Amino Acid Substitution,Animals,Base Sequence,DNA Primers,Evolution, Molecular,Exons,Gene Components,Gene Frequency,Glial Fibrillary Acidic Protein,Humans,Mice,Molecular Sequence Data,Polymorphism, Genetic,Sequence Alignment,Sequence Analysis, DNA,DNA Primers,Glial Fibrillary Acidic Protein
Institute of Human Genetics, University of Aarhus, DK-8000 Aarhus C, Denmark.
Genomics
0888-7543
S088875430300106X
0
False
12837269
