Identification of a functional AP1 element in the rat vasopressin gene promoter.
Arginine vasopressin (AVP) is expressed in paraventricular, supraoptic, and suprachiasmatic nuclei of the hypothalamus, where transcription of the AVP gene is activated by various forms of stress, such as hyperosmolality, inflammation, and photic stimulation. In vasopressinergic neurons, the expression of the Fos/Jun family proteins is known to be rapidly induced after these stimuli as well. However, it is still unknown whether these proteins actually mediate AVP gene expression. In this study we examined in vitro the role of Fos/Jun protein in transcriptional regulation of the AVP gene using the BE(2)M17 neuroblastoma cell line. We found that 5'-promoter activity of the rat AVP gene (-803/+26) markedly increased when all combinations of the Fos/Jun family proteins were overexpressed. Coexpression of the cAMP-responsive element-binding protein-binding protein and steroid receptor coactivator-1a further enhanced the Fos/Jun-mediated transcription. Using site-directed mutagenesis and EMSA techniques, we identified an activation protein 1 (AP1)-like element (-134/-128; TGAATCA) in the AVP gene 5'-promoter region, which is the sole responsible site for the Fos/Jun-mediated transcription. We also found that 12-O-tetradecarbonyl phorbol 13-acetate stimulates AVP gene transcription partly via the AP1 site through the activation of ERK signaling. Together, these results suggest that a variety of Fos/Jun family member proteins stimulate transcription of the AVP gene through the AP1 site we identified. Furthermore, this effect may be activated by both protein kinase A and protein kinase C signaling pathways.
Yoshida
Masanori
M
Department of Endocrinology, Toyota Memorial Hospital, Toyota 471-8513, Japan. masanori_yoshida@mail.toyota.co.jp
Iwasaki
Yasumasa
Y
Asai
Masato
M
Takayasu
Shinobu
S
Taguchi
Takafumi
T
Itoi
Keiichi
K
Hashimoto
Kozo
K
Oiso
Yutaka
Y
D000818:Animals; D001127:Arginine Vasopressin / Q000235:genetics*; D002478:Cells, Cultured; D017868:Cyclic AMP-Dependent Protein Kinases / Q000502:physiology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000502:physiology; D051548:Histone Acetyltransferases; D020935:MAP Kinase Signaling System / Q000502:physiology; D008565:Membrane Proteins / Q000502:physiology; D051379:Mice; D056920:Nuclear Receptor Coactivator 1; D010750:Phosphoproteins / Q000502:physiology; D011401:Promoter Regions, Genetic; D011493:Protein Kinase C / Q000502:physiology; D051381:Rats; D020218:Response Elements; D018808:Transcription Factor AP-1 / Q000502:physiology*; D014157:Transcription Factors / Q000502:physiology
D008565:Membrane Proteins; C408142:Pag1 protein, rat; D010750:Phosphoproteins; D018808:Transcription Factor AP-1; D014157:Transcription Factors; D001127:Arginine Vasopressin; D051548:Histone Acetyltransferases; C538861:Ncoa1 protein, mouse; D056920:Nuclear Receptor Coactivator 1; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C; D048049:Extracellular Signal-Regulated MAP Kinases