Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.24.3 (collagenase)
 18,340 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Gastrin-releasing polypeptide (GRP) has been implicated in the development of the human fetal lung. To determine whether GRP has a wider role in fetal development, its actions on DNA synthesis and cell replication by isolated epiphyseal growth plate chondrocytes obtained from ovine fetuses between 35 days gestation and near term (145 days) were examined. Chondrocytes were isolated using collagenase from the proximal tibia and cultured in monolayer. Synthesis of DNA was assessed from the incorporation of [3H]thymidine into previously growth-restricted cells after incubation in medium supplemented with GRP1-27 (40-1280 nM). Increase in cell number was assessed after incubation with test medium for 1 week. GRP caused a dose-dependent increase in both cell number and DNA synthetic rate compared to control incubations. Cell number was increased by 50% in the presence of a maximally effective 160 nM GRP and DNA synthesis by up to 800% utilizing chondrocytes obtained from animals of 75-80 days gestation. The mean (+/- SEM) half-maximal concentration of GRP for the stimulation of DNA synthesis was 97 +/- 12 nM (5 separate fetuses). Concentrations of GRP in excess of 160 nM caused a sharp reduction in both cell replication and DNA synthesis. To determine where within the cell cycle GRP exerted its mitogenic action, synchronized chondrocytes were transiently exposed to fetal bovine serum and cultured with GRP for increasing periods of time before pulse labeling with [3H]thymidine during S phase. GRP was as effective in stimulating DNA synthesis when present for the initial 4 h of G1 as when present for the entire G1 period. Since isolated fetal growth plate chondrocytes release insulin-like growth factor II (IGF II) and basic fibroblast growth factor (basic FGF) the possible mediation of GRP action by the release of these peptides or synergistic interactions were examined. Specific antibodies shown to negate the mitogenic actions of exogenous IGFs or basic FGF on chondrocytes did not alter GRP-stimulated DNA synthesis. The release of radioimmunoassayable IGF II by chondrocytes was not altered in the presence of GRP. Coincubation of GRP with submaximal concentrations of IGF I or basic FGF showed additive effects on DNA synthesis. When the actions of galanin were examined it was found to inhibit basal DNA synthesis by chondrocytes at a concentration of 167 nM. However, 66 nM or greater galanin was able to render 160 nM GRP inactive as a mitogen. These results suggest that GRP may potentially influence skeletal development in the ovine fetus and may interact with locally released peptide growth factors or other neuropeptides.
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PMID:Mitogenic action of gastrin-releasing polypeptide on isolated epiphyseal growth plate chondrocytes from the ovine fetus. 157 94

Glycine-rich proteins (GRPs) have been found in the cell walls of many higher plants and form a third group of structural protein components of the wall in addition to extensins and proline-rich proteins. The primary sequences of GRPs contain more than 60% glycine. GRPs are localized mainly in the vascular tissue of the plant, and their coding genes provide an excellent system to analyze the molecular basis of vascular-specific gene expression. In French bean, the major cell wall GRP has been localized at the ultrastructural level in the modified primary cell wall of protoxylem. Immunological studies showed that it forms a major part of these highly extensible and specialized cell walls. Specific digestion of GRP1.8 from bean by collagenase suggests that it shares structural similarities with collagen. The protein is synthesized by living protoxylem cells as well as xylem parenchyma cells. After cell death, GRPs are exported from neighboring xylem parenchyma cells to the protoxylem wall, a rare example of protein transport between cells in plants. We propose that GRPs are part of a repair system of the plant during the stretching phase of protoxylem.
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PMID:Glycine-rich proteins as structural components of plant cell walls. 1169 24