Three brain sodium channel alpha-subunit genes are clustered on the proximal segment of mouse chromosome 2.
We have used long-range physical mapping and restriction fragment length polymorphisms between two mouse species to determine the chromosomal organization and location of the genes encoding three distinct isoforms of the alpha-subunit of the brain sodium channel. Physical mapping by pulsed-field gel electrophoresis has established that Scn2a and Scn3a (genes encoding type II and type III sodium channel alpha-subunit isoforms) are physically linked and are separated by a maximum distance of 600 kb. The segregation of restriction fragment length variations in backcross progeny of a Mus musculus and Mus spretus mating indicates that Scn 1 a (gene encoding the type I sodium channel alpha subunit) and Scn2a are tightly linked and are separated by a distance of 0.7 cM. Linkage analysis in backcross and recombinant inbred (BXD and AKXD) strains of mice localized the three sodium channel genes to the proximal segment of mouse chromosome 2 and suggested the probable gene order centromere-Hc-Neb-Pmv7-Scn2a/Scn3a-Scn1a-Mpmv 14. These results indicate that the three isoforms of the brain sodium channel alpha-subunit are encoded by three distinct genes that share a common ancestral origin.
Department of Biochemistry, McGill University, Montreal, Canada.
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Malo
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Schurr
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Dorfman
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Canfield
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Levenson
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Gros
D000015:Abnormalities, Multiple / Q000235:genetics; D000818:Animals; D001483:Base Sequence; D001923:Brain Chemistry; D002874:Chromosome Mapping; D003433:Crosses, Genetic; D005796:Genes; D008040:Genetic Linkage; D005819:Genetic Markers; D051379:Mice / Q000235:genetics*; D008969:Molecular Sequence Data; D009115:Muridae / Q000235:genetics; D009137:Muscular Dystrophy, Animal / Q000235:genetics; D010802:Phylogeny; D012150:Polymorphism, Restriction Fragment Length; D011995:Recombination, Genetic; D015222:Sodium Channels / Q000235:genetics*; D013045:Species Specificity
D005819:Genetic Markers; D015222:Sodium Channels