Gestational and tissue-specific regulation of C1C-2 chloride channel expression.
Chloride channels supply critical functions in epithelial cells throughout the body. Although function of the volume- and voltage-gated C1C-2 is uncertain, its wide tissue distribution of mRNA suggests C1C-2 has important housekeeping functions. This study's objective was to identify the extent of not only C1C-2 mRNA expression but also protein expression as a measure of the capacity for C1C-2 chloride secretion in epithelial tissues. Using quantitative ribonuclease protection assay, we found that C1C-2 mRNA transcripts were abundant in fetal and postnatal brain, fetal kidney, liver, intestine, and lung. In contrast to brain, C1C-2 mRNA transcripts were downregulated during late gestation in lung, kidney, and intestine. The lung expressed the least C1C-2 mRNA. Immunoblotting demonstrated similar tissue- and gestation-dependent variations in C1C-2 protein expression. To determine if there is a correlation between the sites of C1C-2 protein expression and cystic fibrosis transmembrane conductance regulator (CFTR), another epithelial chloride channel, a polyclonal COOH-terminal C1C-2 antibody and an anti-R domain CFTR anti-body were used. C1C-2 and CFTR were expressed in different sites in lung and kidney.
Murray
C B
CB
Eudowood Division of Respiratory Sciences, Johns Hopkins Medical Institutions, Baltimore, Maryland 21287, USA.
Chu
S
S
Zeitlin
P L
PL
D000375:Aging; D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000378:metabolism; D000090007:CLC-2 Chloride Channels; D018118:Chloride Channels / Q000096:biosynthesis*; D005314:Embryonic and Fetal Development; D005260:Female; D005333:Fetus; D018507:Gene Expression Regulation, Developmental; D005865:Gestational Age; D007150:Immunohistochemistry; D007413:Intestinal Mucosa / Q000378:metabolism; D007668:Kidney / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008168:Lung / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000096:biosynthesis*; D009928:Organ Specificity; D011247:Pregnancy; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D014158:Transcription, Genetic
D000090007:CLC-2 Chloride Channels; D018118:Chloride Channels; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger