Regulation of NHE1 expression in L6 muscle cells.
We examined regulation of expression of the NHE1 promoter on rat L6 cells. Transient transfection of these cells showed that there are two regions critical for basal expression in this cell type. One is from bp -155 to -171 and second more proximal region is between bp -92 and -125. When cells were induced to differentiate by serum withdrawal, mRNA levels rose 2-3-fold. To investigate the mechanisms of this phenomenon a series of stable transfectants were made of the NHE1 promoter in L6 cells. Muscle differentiation caused a significant stimulation of transcriptional activity in the stable cells containing the more distal regions of the promoter. The results show that basal expression of the NHE1 promoter is mediated largely by two proximal regions of the gene. However, during the process of differentiation more distal regions of the gene are involved in elevation of the level of expression.
Yang
W
W
Department of Pediatrics, Faculty of Medicine, University of Alberta, Edmonton, Canada.
Dyck
J R
JR
Fliegel
L
L
D000818:Animals; D001483:Base Sequence; D002118:Calcium / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D016895:Culture Media, Serum-Free / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects; D017930:Genes, Reporter; D051379:Mice; D008969:Molecular Sequence Data; D009124:Muscle Proteins / Q000096:biosynthesis* / Q000235:genetics; D018482:Muscle, Skeletal / Q000166:cytology / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D051381:Rats; D017923:Sodium-Hydrogen Exchangers / Q000096:biosynthesis* / Q000235:genetics; D014162:Transfection
D016895:Culture Media, Serum-Free; D009124:Muscle Proteins; D012333:RNA, Messenger; D017923:Sodium-Hydrogen Exchangers; D002118:Calcium