title: Cloning, chromosomal localization, and physical linkage of the beta and gamma subunits (SCNN1B and SCNN1G) of the human epithelial amiloride-sensitive sodium channel.
abstract: Three subunits of the amiloride-sensitive Na+ channel, named alpha, beta, and gamma, have previously been cloned in rat colon. The human lung alpha chain (SCNN1A) has also been cloned and its gene localized on chromosome 12p13. We now report the molecular cloning of the human lung beta (SCNN1B) and gamma (SCNN1G) chains. In situ hybridization and pulsed-field electrophoresis experiments demonstrate that both genes are located within a common 400-kb fragment on chromosome 16p12-p13. Screening of the cDNA library reveals two forms of the beta subunit that differ by the presence or absence of a 464-bp fragment in the 3' region. A frameshift in the short form modifies the COOH terminal sequence of the corresponding protein. Since several similar frameshifts mutations have recently been reported in patients affected by a rare form of hypertension, the existence of COOH truncated forms of the beta chain might be of physiological importance.
mesh_terms: D000584:Amiloride / Q000494:pharmacology; D000595:Amino Acid Sequence; D001483:Base Sequence; D002874:Chromosome Mapping; D002885:Chromosomes, Human, Pair 16; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000032:analysis; D053503:Epithelial Sodium Channels; D004848:Epithelium; D006801:Humans; D008969:Molecular Sequence Data; D015222:Sodium Channels / Q000187:drug effects / Q000235:genetics*
chemical_list: D018076:DNA, Complementary; D053503:Epithelial Sodium Channels; C507045:SCNN1A protein, human; C507048:SCNN1B protein, human; C507052:SCNN1G protein, human; C507050:Scnn1b protein, rat; C507054:Scnn1g protein, rat; D015222:Sodium Channels; D000584:Amiloride