Bovine CACNA1A gene and comparative analysis of the CAG repeats associated to human spinocerebellar ataxia type-6.
A small expansion of a CAG repeat domain in exon 47 of the human CACNA1A gene, which codes for the pore-forming alpha1A subunit of P/Q-type Ca2+ channels, causes spinocerebellar ataxia type-6. Only the human alpha1A protein has been demonstrated to contain the poly(Q) tract, although this locus has also recently been detected in ape genomes. To our knowledge, no further information has been published on other mammal species. Here, we have cloned the full-length alpha1A subunit in a non-primate species, the cow. The results have made it possible to explore the exon organization of the bovine CACNA1A gene as well as the splice alpha1A isoforms expressed by bovine chromaffin cells. We found a splice variant of the protein that, as in humans, also contains a polymorphic poly(Q) tract. Based on this result and using data from different Genome Databases, we performed an interspecies comparison of exon 47 and discovered that the poly(Q) tract is present in all the species studied, with the exception of primitive fish and rodents. Our results provide insight into the evolution of the CAG repeat tract at the C-terminus coding region of the CACNA1A gene.
Andrés-Mateos
Eva
E
Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, Arzobispo Morcillo 4, 28029-Madrid, Spain.
Cruces
Jesús
J
Renart
Jaime
J
Solís-Garrido
Luisa M
LM
Serantes
Rocío
R
de Lucas-Cerrillo
Ana M
AM
Montiel
Carmen
C
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015220:Calcium Channels / Q000235:genetics; D020865:Calcium Channels, P-Type / Q000235:genetics*; D020907:Calcium Channels, Q-Type / Q000235:genetics*; D002417:Cattle; D002478:Cells, Cultured; D019439:Chromaffin Cells / Q000378:metabolism; D003001:Cloning, Molecular; D017931:DNA Primers / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D019143:Evolution, Molecular; D005091:Exons; D006801:Humans; D007438:Introns; D008969:Molecular Sequence Data; D020033:Protein Isoforms / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D013045:Species Specificity; D020754:Spinocerebellar Ataxias / Q000235:genetics*; D018911:Trinucleotide Repeats; D020864:Calcium Channels, N-Type
D015220:Calcium Channels; D020865:Calcium Channels, P-Type; D020907:Calcium Channels, Q-Type; D017931:DNA Primers; D018076:DNA, Complementary; D020033:Protein Isoforms; C105656:CACNA1A protein, human; D020864:Calcium Channels, N-Type