Troglitazone, a ligand of peroxisome proliferator-activated receptor-{gamma}, stabilizes NUCB2 (Nesfatin) mRNA by activating the ERK1/2 pathway: isolation and characterization of the human NUCB2 gene.
We recently identified a novel satiety peptide, nesfatin-1, containing 82 amino acids derived from the precursor peptide, nucleobindin 2 (NUCB2), from a troglitazone (TZ)-induced cDNA library. We examined the molecular mechanism underlying TZ-induced NUCB2 mRNA expression. Although TZ induced the mRNA expression in HTB185 cells, a nuclear run-on assay revealed no significant change in the transcription of the gene. Surprisingly, HTB185 cells possessed no functional peroxisome proliferator-activated receptor-gamma. We therefore examined the effect of TZ on the mRNA's stability. The half-life of NUCB2 mRNA was approximately 6 h, and incubation with TZ increased this to 27 h. Furthermore, this increase was completely inhibited by an ERK inhibitor, PD98059, and phosphorylated ERK1/2 was significantly increased after 30 min incubation with TZ. In addition, we cloned the entire NUCB2 gene and identified four adenylate/uridylate-rich elements (AREs) in the 3' untranslated region (UTR), to which several proteins of HTB185 extracts treated with TZ bound. The reporter assay fused with 3'UTR showed that the second and third AREs were crucial. Furthermore, the human NUCB2 gene spanned 55 kb and contained 14 exons and 13 introns. The transcriptional start site formed clusters around 246 bp upstream from the translational start site. We confirmed that a construct containing 5889 bp of the promoter region was very active in neuron-derived cell lines but not stimulated by TZ. These findings demonstrated a novel action of derivatives of thiazolidinediones, oral insulin-sensitizing antidiabetic agents, to stabilize the mRNA of NUCB2 through AREs in the 3'UTR by activating the ERK1/2 pathway independently of peroxisome proliferator-activated receptor-gamma.
Yamada
Masanobu
M
Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, 3-39-15 Showa-machi, Maebashi, Gunma 371-8511, Japan. myamada@med.gunma-u.ac.jp
Horiguchi
Kazuhiko
K
Umezawa
Ryohei
R
Hashimoto
Koshi
K
Satoh
Tetsurou
T
Ozawa
Atsushi
A
Shibusawa
Nobuyuki
N
Monden
Tsuyoshi
T
Okada
Shuichi
S
Shimizu
Hiroyuki
H
Mori
Masatomo
M
D001483:Base Sequence; D015152:Blotting, Northern; D015153:Blotting, Western; D002135:Calcium-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D002460:Cell Line; D002839:Chromans / Q000494:pharmacology*; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D006367:HeLa Cells; D006801:Humans; D007004:Hypoglycemic Agents / Q000494:pharmacology; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins; D000080866:Nucleobindins; D047495:PPAR gamma / Q000819:agonists*; D016133:Polymerase Chain Reaction; D020871:RNA Stability / Q000187:drug effects; D012333:RNA, Messenger / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects* / Q000235:genetics; D045162:Thiazolidinediones / Q000494:pharmacology*; D000077288:Troglitazone
D002135:Calcium-Binding Proteins; D002839:Chromans; D004268:DNA-Binding Proteins; D007004:Hypoglycemic Agents; C000630650:NUCB2 protein, human; D009419:Nerve Tissue Proteins; D000080866:Nucleobindins; D047495:PPAR gamma; D012333:RNA, Messenger; D045162:Thiazolidinediones; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D000077288:Troglitazone