Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P01189 (beta-endorphin)
 21,003 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The pro-opiomelanocortin gene is widely expressed in human tissues, although both transcriptional initiation sites and regulation appear to be tissue specific. In order to determine how promoter and enhancer choice is effected, we have studied the methylation pattern of the gene in a number of normal tissues, tumours and cell lines. Variability of this pattern was observed in the 5'-flanking DNA, particularly at the HpaII site located at -304 bp upstream from the pituitary CAP site. This site was generally methylated in tissues likely to express the predominant extrapituitary (800 nucleotide) message, while in tissues known to express the normal pituitary (1150 nucleotide) message and longer species, a tendency towards undermethylation was observed. Although the sites at which variable methylation occurs did not correspond to established binding sites for regulatory proteins, many of these regions remain to be determined and thus it is possible that methylation may be influential in the tissue-specific regulation of this gene.
 ...
PMID:Variable methylation of the 5'-flanking DNA of the human pro-opiomelanocortin gene. 201 57

Enucleation techniques combining mild centrifugation in the presence of cytochalasin B permit cells to be separated into nuclear fragments (karyoplasts) and cytoplasmic fragments (cytoplasts). These fragments, though stable for a short time, will ultimately degenerate by the procedures described in this report. One can, however, fuse cytoplasts to karyoplasts by using polyethylene glycol and obtain viable reconstituted cells whose properties may be useful for understanding some aspects of the nuclear-cytoplasmic interactions associated with tumorigenicity and steroidogenesis. However, the presence of cybrids, hybrids, and parental whole cell contaminants along with the reconstituted cell population make it necessary to have genetic markers that reside in both the nucleus and cytoplasm in order to preferentially identify reconstituted cells derived from a karyoplast fused to a cytoplast. By utilizing the Y-1 cell line, which is tumorigenic and responds to corticotropin by secreting steroids, and the AMT-BU-A1 (AMT) cell line, which is nontumorigenic and does not respond to corticotropin but has a nuclear marker, BrdUrd(r), and a cytoplasmic marker, CAP(r), we have reconstituted cells containing Y-1 karyoplasts and AMT cytoplasts. In this report we extend our previous techniques by describing an identification procedure that allowed us to isolate cells reconstituted from AMT karyoplasts fused to Y-1 cytoplasts. The results of these experiments support the concept that with these cell lines the nucleus (karyoplast) is ultimately sufficient to control the phenotypic expression or suppression of tumorigenicity and steroidogenesis.
 ...
PMID:Alternative method for identifying reconstituted cells. 624 55

Fluid secretion by insect Malpighian tubules is controlled by haemolymph-borne factors. The mealworm Tenebrio molitor provides the first known example of antagonistic interactions between endogenous neuropeptides acting on Malpighian tubules. The two corticotropin-releasing-factor (CRF)-related diuretic peptides previously isolated from Tenebrio molitor, Tenmo-DH(37) and Tenmo-DH(47), were found to stimulate Tenebrio molitor tubules in vitro in a dose-dependent manner with EC(50) values of 0.12 nmol l(-1) and 26 nmol l(-1) respectively. However, no synergistic or additive effect was observed when these two peptides were tested simultaneously. We then investigated antagonism between second messengers: dose-response curves were constructed for stimulation of Tenebrio molitor tubules by cyclic AMP and their inhibition by cyclic GMP. When both cyclic nucleotides were included in the bathing Ringer, the stimulatory effect of cyclic AMP was neutralised by cyclic GMP. Similarly, the stimulatory effect of Tenmo-DH(37) was reversed on addition of an antidiuretic peptide (Tenmo-ADF), which was recently isolated from Tenebrio molitor and acts via cyclic GMP. The cardioacceleratory peptide CAP(2b), originally isolated from Manduca sexta, also increases intracellular cyclic GMP levels and inhibited fluid secretion by Tenebrio molitor tubules, with an EC(50) value of 85 nmol l(-1). This inhibitory effect was reversed by Tenmo-DH(37). Endogenous diuretic and antidiuretic peptides, effective at low concentrations and acting via antagonistic second messengers, have the potential for fine control of secretion rates in the Malpighian tubules of Tenebrio molitor.
 ...
PMID:Antagonistic control of fluid secretion by the Malpighian tubules of Tenebrio molitor: effects of diuretic and antidiuretic peptides and their second messengers. 1189 63