Mineralocorticoid hormone receptor and the epithelial sodium channel in a human leukemic cell line

A Cell extract from the HEL (human erythroblastic leukemia) cell line was p ositive for both the epithelial sodium channel (ENaC) and the mineralocorti coid receptor (MCR) as glycosylated 82-84 kDa bands, and a single 102 kDa b and, respectively, in Western blots using polyclonal antibodies raised agai nst these proteins. The immunofluorescent labeling of the MCR in all cell l ines showed a nucleocytoplasmic localization of the receptor whereas the EN aC was exclusively membrane-bound. These results were confirmed by confocal microscopy. The expression of the MCR in HEL cells was evident as a predic ted band of 843 bp (234 amino acids) after total RNA from HEL cells had bee n reverse transcribed and then amplified by PCR; the ENaC was similarly evi dent as a predicted band of 520 bp. In both cases, near 100% identity was o bserved between the deduced amino acid sequences of the PCR products and th ose from known human sources. The multiplication of HEL cells was influence d by antagonists (RU 26752, ZK 91587) targeted for specificity to the MCR a nd this was reversed by the natural hormone aldosterone. These steroids als o provoked chromatin condensation in the HEL population.