Thyroid transcription factor-1 exhibits osmosensitive transcription in brain-derived cell lines.
Thyroid transcription factor-1 (TTF-1) belongs to the Nkx family of homeodomain-containing proteins and regulates expression of several important genes in the brain. Our previous studies showed that TTF-1 plays an important role in water homeostasis in the subfornical organ of rats and is involved in cerebrospinal fluid formation by regulation of aquaporin-1 transcription in the choroid plexus. In this study, we examined changes in TTF-1 transcription in response to hypertonicity using promoter assays. TTF-1 was synthesized in several osmosensitive regions of the rat brain. TTF-1 promoter activity was diminished by treatment with hypertonic solutions in a time- and dose-dependent manner in brain-derived cell lines. Additionally, TTF-1 was involved in the regulation of angiotensinogen (Aogen) transcription under a hyperosmotic condition through specific binding domains in the Aogen promoter. These results suggest a possible role of TTF-1 in brain fluid homeostasis in response to changes in the osmotic environment.
Kim
Jae Geun
JG
Department of Biological Sciences, College of Natural Sciences, University of Ulsan, San29, Mugeodong, Namgu, Ulsan 680-749, Republic of Korea.
Bae
Kyung Duk
KD
Yun
Chang Ho
CH
Im
Hye Li
HL
Park
Jeong Woo
JW
Nam-Goong
Il Seong
IS
Kim
Young Il
YI
Lee
Byung Ju
BJ
D000808:Angiotensinogen / Q000235:genetics*; D000818:Animals; D001921:Brain / Q000378:metabolism*; D002460:Cell Line; D005786:Gene Expression Regulation / Q000187:drug effects; D008297:Male; D009687:Nuclear Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D009995:Osmosis; D009997:Osmotic Pressure; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012965:Sodium Chloride / Q000494:pharmacology; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors / Q000032:analysis / Q000235:genetics / Q000378:metabolism*
C000614416:Nkx2-1 protein, rat; D009687:Nuclear Proteins; D012333:RNA, Messenger; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors; D000808:Angiotensinogen; D012965:Sodium Chloride