A Prospero-related homeodomain protein is a novel co-regulator of hepatocyte nuclear factor 4alpha that regulates the cholesterol 7alpha-hydroxylase gene.
*Gene Expression Regulation; Aged; Amino Acid Motifs; Bile Acids and Salts/metabolism; Cell Line; Cell Nucleus/metabolism; Cells; Cholesterol 7-alpha-Hydroxylase/*chemistry/*genetics; Cultured/metabolism; Enzymologic; Female; Genes; Genetic; Gluconeogenesis; Glutathione Transferase/metabolism; Hepatocyte Nuclear Factor 4/metabolism/*physiology; Hepatocytes/metabolism; Homeodomain Proteins/metabolism/*physiology; Humans; Immunoprecipitation; Liver/metabolism; Luciferases/metabolism; Male; Messenger/metabolism; Middle Aged; Phosphoenolpyruvate Carboxykinase (ATP)/metabolism; Plasmids/metabolism; Protein Structure; Reporter; Response Elements; Reverse Transcriptase Polymerase Chain Reaction; RNA; Small Interfering/metabolism; Tertiary; Time Factors; Transcription; Transcriptional Activation; Transfection; Tumor Suppressor Proteins; Two-Hybrid System Techniques
Prox1, an early specific marker for developing liver and pancreas in foregut endoderm has recently been shown to interact with alpha-fetoprotein transcription factor and repress cholesterol 7alpha-hydroxylase (CYP7A1) gene transcription. Using a yeast two-hybrid assay, we found that Prox1 strongly and specifically interacted with hepatocyte nuclear factor (HNF)4alpha, an important transactivator of the human CYP7A1 gene in bile acid synthesis and phosphoenolpyruvate carboxykinase (PEPCK) gene in gluconeogenesis. A real time PCR assay detected Prox1 mRNA expression in human primary hepatocytes and HepG2 cells. Reporter assay, GST pull-down, co-immunoprecipitation, and yeast two-hybrid assays identified a specific interaction between the N-terminal LXXLL motif of Prox1 and the activation function 2 domain of HNF4alpha. Prox1 strongly inhibited HNF4alpha and peroxisome proliferators-activated receptor gamma coactivator-1alpha co-activation of the CYP7A1 and PEPCK genes. Knock down of the endogenous Prox1 by small interfering RNA resulted in significant increase of CYP7A1 and PEPCK mRNA expression and the rate of bile acid synthesis in HepG2 cells. These results suggest that Prox1 is a novel co-regulator of HNF4alpha that may play a key role in the regulation of bile acid synthesis and gluconeogenesis in the liver.
Song Kwang-Hoon; Li Tiangang; Chiang John Y L
The Journal of biological chemistry
2006
2006-04
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1074/jbc.M513420200" target="_blank" rel="noreferrer noopener">10.1074/jbc.M513420200</a>
Sensory nerves and neuropeptides in uterine cervical ripening.
Animal; Animals; Calcitonin Gene-Related Peptide/biosynthesis; Capsaicin/pharmacology; Cervical Ripening/*metabolism; Cervix Uteri/*innervation/*metabolism; Complementary/metabolism; Female; Genetic; Immunohistochemistry; Labor; Messenger/metabolism; Neurokinin-1/biosynthesis; Neurons/metabolism; Neuropeptides/*biosynthesis; Nitric Oxide Synthase/biosynthesis; Obstetric; Plasmids/metabolism; Postpartum Period; Pregnancy; Rats; Receptors; RNA; Secretogranin II; Sprague-Dawley; Substance P/biosynthesis; Transcription
At the time of parturition (fetal delivery) the uterine cervix must "ripen," becoming soft, pliable, and dilated to accommodate the fetus' delivery. The fundamental processes underlying cervical ripening remain poorly understood. Knowledge that abundant autonomic and sensory nerves supply the uterine cervix, that transection of afferent nerves supplying the cervix blocks parturition, and that some of the changes in the cervix resemble those seen in inflammatory reactions suggests nerves may have a role in the cervical ripening changes. The present study utilized immunohistochemistry, plasma extravasation, and solution hybridization-nuclease protection assay to elucidate the complement of primary afferent nerves and some receptors in the rat cervix during pregnancy, and to determine if they may have roles in the ripening process at term. This study revealed an abundance of nerves associated with the cervical vasculature and myometrial smooth muscle containing immunoreactivity for substance P, calcitonin gene-related peptide, secretoneurin, and nitric oxide synthase throughout pregnancy. Many of these are small unmyelinated capsaicin-sensitive C-fibers. Substance P- (NK1-) and calcitonin gene-related peptide receptors were apparent on uterine cervix vasculature from pregnant, parturient, and postpartum rats. NK1 receptor mRNA was maximal at 20 days of pregnancy. Plasma extravasation of i.v. administered Evans Blue or Monastral Blue was most pronounced at parturition (shortly after NK1 mRNA is maximal); this was similar to plasma extravasation evoked by i.v. administration of substance P or capsaicin-treatment. This study revealed new data about the nervous system of the rat uterine cervix and that these nerves and their transmitters could very well be part of a neurogenic inflammatory process involved in cervical ripening.
Collins J J; Usip S; McCarson K E; Papka R E
Peptides
2002
2002-01
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1016/s0196-9781(01)00593-9" target="_blank" rel="noreferrer noopener">10.1016/s0196-9781(01)00593-9</a>