Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01178 (oxytocin)
 15,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Abstract An antiserum to neurohypophyseal prohormones was generated by immunization of rabbits with a synthetic peptide fragment bridging the prohormone cleavage site between the vasopressin (AVP) and human AVP-neurophysin sequences of pro-pressophysin. Polyclonal antibodies directed against this peptide cross-reacted with intact human pro-pressophysin (ED(50) of 260fmol), but not with either of the final products of enzymatic processing, AVP and human AVP-neurophysin. Gel electrophoresis and Western immunoblotting of pituitary or hypothalamic extracts from multiple species including mouse, cow and man identified a protein band of molecular weight consistent with intact pro-pressophysin; in hypothalamic extracts from normally-hydrated rats no protein bands were stained, but in extracts from Brattleboro rats a faint band in the area of pro-oxyphysin was identified. Immunohistochemical studies using the antiserum demonstrated the presence of only very small amounts of immunoreactive prohormone in a few widely scattered cells in the hypothalami of normally-hydrated rats. However, after 5 days of solute loading with 2% NaCl as drinking solution, staining for intact prohormone was prominent in the supraoptic and paraventricular nuclei of the hypothalamus. Combined immunoperoxidase-immunofluorescence labeling for prohormone and either AVP-neurophysin or oxytocin-neurophysin revealed prohormone staining in both types of magnocellular neurons in rat hypothalami. These studies suggest that during states of accelerated synthesis and secretion of neurohypophyseal hormones some accumulation of intact prohormone occurs in both AVP and oxytocin magnocellular neurons.
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PMID:Generation and characterization of an antiserum directed against neurohypophyseal prohormones. 1921 63

The expression of hormone-inducible genes is determined by the interaction of trans-acting factors with hormone-inducible elements and elements mediating basal and cell-specific expression. We have shown earlier that the gene encoding the hypothalamic nonapeptide oxytocin (OT) is under the control of an estrogen response element (ERE). The present study was aimed at identifying cis-acting elements mediating basal expression of the OT gene. A construct containing sequences -381 to +36 of the human OT gene was linked to a reporter gene and transiently transfected into a series of neuronal and nonneuronal cell lines. Expression of this construct was cell specific: it was highest in the neuroblastoma-derived cell line, Neuro-2a, and lowest in NIH 3T3 and JEG-3 cells. By 5' deletion analysis, we determined that a segment from -49 to +36 was capable of mediating cells-pecific promoter activity. Within this segment, we identified three proximal promoter elements (PPE-1, PPE-2, and PPE-3) that are each required for promoter activity. Most notably, mutation of a conserved purine-rich element (GAGAGA) contained within PPE-2 leads to a 10-fold decrease in promoter strength. Gel mobility shift analysis with three different double-stranded oligonucleotides demonstrated that each proximal promoter element binds distinct nuclear factors. In each case, only the homologous oligonucleotide, but neither of the oligonucleotides corresponding to adjacent elements, was able to act as a competitor. Thus, a different set of factors appears to bind independently to each element. By reinserting the homologous ERE or a heterologous glucocorticoid response element upstream of intact or altered proximal promoter segments we determined that removal or mutation of proximal promoter elements decreases basal expression, but does not abrogate the hormone responsiveness of the promoter. In conclusion, these results indicate that an important component of the transcriptional activity of the OT promoter resides in a small region extending only 50 bases upstream of the cap site and that this activity is the result of a cooperative interaction of at least three distinct proximal promoter elements.
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PMID:Identification of cis-acting regulatory elements in the human oxytocin gene promoter. 1991 35


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