Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.27.4 (ribonuclease)
 6,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Transforming growth factor alpha (TGF-alpha) is expressed in the brain and affects cells by binding to the epidermal growth factor receptor (EGF-R). Using a ribonuclease protection assay, we found that TGF-alpha steady state mRNA levels in the mouse striatum peak during the first week of postnatal life. Temporally this peak correlates with the height of gliogenesis in the subependymal layer (SEL), which lies along the striatal border of the lateral ventricle. In vitro studies demonstrate that TGF-alpha can stimulate the proliferation of astrocytes, so glial fibrillary acidic protein (GFAP) mRNA levels were measured as well and it was observed that the peak of GFAP expression followed that of TGF-alpha by 1 week. Furthermore, in a TGF-alpha deficient mouse, waved-1 (wa-1), a significant reduction of GFAP mRNA levels and immunostaining for GFAP was found in the striatum. Bromodeoxyuridine labeling combined with immunohistochemistry of normal postnatal day 6 brain showed that the proliferating cells in the SEL are EGF-R immunoreactive. In the waved-1 SEL, there were fewer BrdU positive cells and there was a reduced level of [3H]thymidine incorporation. EGF-R immunoreactive cells were found in the SEL of the adult mouse brain. Taken together, our data suggest that the TGF-alpha/EGF-R signaling pathway is involved in postnatal mitogenic events in the brain.
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PMID:Striatal TGF-alpha: postnatal developmental expression and evidence for a role in the proliferation of subependymal cells. 765 13

The molecular mechanisms by which endometriosis persists in locations outside the uterus are unclear. Recently, the epidermal growth factor receptor (EGF-R) has been postulated to have a role in the disease process of endometriosis. To explore this, we determined the levels of EGF-R protein and messenger ribonucleic acid (mRNA) expression in endometriotic tissues and compared the levels to that of eutopic endometrium. Using rabbit anti-EGF-R antibody, we found more intense immunohistochemical staining for EGF-R in glandular cells than in stromal cells of both endometriomas and endometriotic implants. No difference in staining intensity was noted between endometriotic tissues and eutopic endometrium. A ribonuclease protection assay was used to determine mRNA levels for EGF-R. PhosphoImager analysis revealed the following levels of mRNA for EGF-R; eutopic endometrium, 1.00 +/- 0.27 (arbitrary units; mean +/- SEM; n = 6 patients); cyst walls of endometriomas, 0.21 +/- 0.12 (n = 10 patients); endometriotic implants, 0.29 +/- 0.13 (n = 9 patients); and pelvic adhesions, 0.03 +/- 0.03 (n = 5 patients). Endometriotic tissues had significantly less mRNA for EGF-R than eutopic endometrium (P < 0.05, by Newman-Keuls test). Our findings support the hypothesis that EGF-R may be associated with the disease process of endometriosis.
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PMID:Quantitative analysis of epidermal growth factor receptor gene expression in endometriosis. 796 80

Betacellulin (BTC) is relatively a more recently discovered member of the EGF family of growth factors. As a prelude to its expression and functional studies in rat models of gut damage/repair, we have cloned rat BTC and examined its expression in the gastrointestinal tract. Rat BTC was found to be nearly identical to mouse betacellulin. A single 3 kb mRNA species was detected by Northern blotting, and ribonuclease protection analysis showed that its expression was ubiquitous but low in abundance throughout the gut. BTC mRNA and protein were found expressed in the gastric surface and upper pit epithelium as well as in some cells of gastric glands. In the jejunum, BTC mRNA and protein were localised to the crypt epithelium and in villous goblet cells. In the colon, BTC mRNA and protein were found produced in crypt and surface epithelium as well as in goblet cells. Taken together, the wide spread expression in the gut epithelium and in mucous cells in particular suggests an important and unique role for BTC in the gastrointestinal tract.
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PMID:Cloning of rat betacellulin and characterization of its expression in the gastrointestinal tract. 1133 56

The epidermal growth factor receptor (EGFR) and related family members (ERBB2, ERBB3, and ERBB4) previously have been shown to play pivotal roles in the development of female reproductive tissues, in blastocyst implantation, and in placental differentiation. We have cloned and sequenced several naturally occurring alternative transcripts of the human and mouse EGFR genes, which encode novel receptor isoforms containing varying portions of the extracellular ligand-binding domain, but lacking the transmembrane and cytoplasmic domain sequences. The human 1.8-kb and 3-kb alternative EGFR transcripts encode secreted 60-kDa and cell surface-associated 110-kDa EGFR isoforms, respectively. We have developed quantitative ribonuclease protection assays to study the expression of these alternative transcripts in human tissues. Similar to the full-length EGFR mRNAs, the highest expression level of these alternative transcripts occurs in placenta. We speculate that both of these EGFR isoforms may be important regulators of EGF-mediated cell growth and differentiation in human placenta.
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PMID:Characterization and expression of novel 60-kDa and 110-kDa EGFR isoforms in human placenta. 1281 37