Structural and Functional Characterization of Human Potassium Channel Subunit β1 (KCNA1B)
Section snippets
Isolation and analysis of cDNA clones
A human brain cDNA library in λgt10 (Clontech.) was hybridized in 6 × SET (15 mM Tris-HCl (pH 7.4), 75 mM NaCl, 0.5 mM EDTA), 1% SDS, 30% formamide, 5 × Denhardt's solution and 0.1 mg/ml denatured herring testis DNA at 42°C with a rat Kvβ1.1 cDNA probe (Rettig et al., 1994) labelled by random priming (Feinberg and Vogelstein, 1983) with (α- 32P)dCTP. Filters were washed in 1 × SET, 0.1% SDS at 50°C. Exposure to X-ray films (Kodak XAR5) was overnight with an amplifying screen (Cronex Hi+,
Characterization of the Kvβ1 gene
The characteristics of the derived Kvβ1 protein sequences Kvβ1.1, Kvβ1.2, Kvβ1.3 (Rettig et al., 1994; England et al. (1995a), England et al. (1995b); McCormack et al., 1995; Majumder et al., 1995; Morales et al., 1995) suggested that they are splice variants produced from a common Kvβ1 gene. This was confirmed by genomic DNA sequence analysis and by genomic mapping. The Kvβ1 (KCNA1B) gene has been mapped by hybridizing Kvβ1.2 probes to somatic cell hybrid panels to chromosome 3 (England et
DISCUSSION
Kv channels purified from rat (Rehm and Lazdunski, 1988) and bovine brain (Parcej and Dolly, 1989) are heterooligomeric complexes consisting of two different types of subunits: membrane-bound pore-forming α subunits and the smaller, auxiliary β subunits. They appear to be tightly associated with cytoplasmic, amino terminal domains of the Kv1α subunits (Sewing et al., 1996; Yu et al., 1996). Thus, Kv channels may form α4β4 heteromultimers in vivo (Parcej et al., 1992). It may be hypothesized
Acknowledgements
The work in this paper was supported by the Deutsche Forschungsgemeinschaft and the Fonds der Chemischen Industrie.
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