Identification of the second tonicity-responsive enhancer for the betaine transporter (BGT1) gene.
When certain cells are exposed to a hypertonic solution, transcription of the BGT1 gene is markedly increased. The ensuing rise in betaine transport leads to cellular accumulation of betaine that protects the cells from the stress of hypertonicity. We have previously identified a tonicity-responsive enhancer (TonE1) in the 5' flanking region of the BGT1 gene. It was recognized, however, that full activation of transcription requires additional sequence upstream from the TonE1. Now we report that there is another TonE (named TonE2) 72 base pairs upstream from the TonE1. TonE1 and TonE2 act synergistically to stimulate transcription of BGT1 in response to hypertonicity.
Miyakawa
H
H
Division of Nephrology, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA.
Rim
J S
JS
Handler
J S
JS
Kwon
H M
HM
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002352:Carrier Proteins / Q000235:genetics*; D002460:Cell Line; D004285:Dogs; D004742:Enhancer Elements, Genetic; D050485:GABA Plasma Membrane Transport Proteins; D006982:Hypertonic Solutions / Q000494:pharmacology*; D007668:Kidney / Q000378:metabolism; D008156:Luciferases / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis; D020218:Response Elements; D015534:Trans-Activators / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects; D014162:Transfection
D002352:Carrier Proteins; D050485:GABA Plasma Membrane Transport Proteins; D006982:Hypertonic Solutions; D012333:RNA, Messenger; D015534:Trans-Activators; C072207:betaine plasma membrane transport proteins; D008156:Luciferases