Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.30.2 (endonuclease)
 18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

During the perinatal period, oligodendroglial precursor cells proliferate rapidly, then cease dividing and differentiate into oligodendroglia. Many of these newly formed oligodendroglia are destined to die. We now demonstrate that oligodendroglia generated in passaged cultures of rat forebrain oligodendroglial precursor cells after removal of basic fibroblast growth factor (basic FGF) from the medium often undergo internucleosomal DNA nicking and nuclear fragmentation, features characteristic of apoptosis. These alterations are rare in cultures maintained continuously in basic FGF. As in many other cellular lineages susceptible to apoptosis, these degenerative changes can be prevented by treatment with the endonuclease antagonist, aurintricarboxylic acid, or by inhibiting de novo RNA or protein synthesis. Supplementation of the basic FGF-free medium with insulin, insulin-like growth factor-1, platelet-derived growth factor, or ciliary neuronotrophic growth factor also diminishes DNA nicking. Both oligodendroglial differentiation and DNA nicking are induced in basic FGF-treated cultures by inhibiting DNA synthesis with aphidicholin or excess thymidine, thus suggesting a close linkage between the anti-apoptotic, anti-differentiation, and mitogenic effects of basic FGF on the oligodendroglial lineage.
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PMID:Apoptosis occurs in the oligodendroglial lineage, and is prevented by basic fibroblast growth factor. 774 24

In previous studies we had found that at late stages of development, when the early patterning control mechanism have ceased to act, the chick limb bud is able to form fully differentiated extradigits by subjecting the interdigital spaces to ectoderm removal. In this study we attempted to mimic this phenomenon by using local microinjections of substances which presumably have a biological action on the interdigital mesenchyme. Microinjection of staurosporine results in the formation of fully differentiated extradigits. The action of this drug appears to be due to the induction of chondrogenesis after the inhibition of the protein kinase C. Zinc chloride administration also causes ectopic chondrogenesis but it seems to act by arresting the interdigital cell death program through endonuclease inhibition. A clear differentiation of the zinc-induced cartilages into extradigits was no detected. This can be explained by the accompanying damage caused by zinc in the growing limb mesenchyme as deduced by the high incidence of hypophalangy in the normal digits. Both TGF beta 1 and TGF beta 2 have a weak effect as inducers of interdigital chondrogenesis; presumably they act by inducing chondrogenetic differentiation. Neither FGF nor EGF has any effect when administered by local microinjection. These results show that ectopic interdigital chondrogenesis induced by drug administration results in the differentiation of extradigits. This suggests that once a cartilage is formed in the autopodium it triggers a new signalling stage which leads to the morphogenesis of a digit. This morphogenetic process involves the patterning of skeleton, joints and tendons. In accordance with these observations, it can be proposed that early patterning of the limb results in the establishment of an autopodium with a defined but still plastic skeletal distribution pattern, while morphogenesis of each autopodial element would take place at a second stage by the activation of new signalling processes.
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PMID:In vivo experimental induction of interdigital tissue chondrogenesis in the avian limb bud results in the formation of extradigits. Effects of local microinjection of staurosporine, zinc chloride and growth factors. 830 89

Oxidative stress is considered a major mediator of apoptosis in several cellular systems. Peroxynitrite is a highly toxic oxidant formed by the reaction of nitric oxide with superoxide. Primary embryonic murine fibroblasts, exposed to 1 mM peroxynitrite, resulted in delayed cell death characterized by membrane blebbing, cytoplasmic shrinkage, nuclear condensation, and DNA fragmentation that were more characteristic of apoptosis than necrosis. In addition, both morphological alterations and DNA fragmentation were inhibited by the endonuclease inhibitor aurintricarboxylic acid. Pretreatment of fibroblasts with acidic fibroblast growth factor (FGF-1) markedly enhanced peroxynitrite-induced apoptosis, an observation restricted to immediate-early transcriptional and activated tyrosine phosphorylation processes. FGF-1 pretreatment had no modulatory effect on cell death elicited by other reactive oxygen species, suggesting that enhancement of apoptosis involves a unique relationship between peroxynitrite and the growth factor. Exposure of cells to peroxynitrite resulted in immediate tyrosine nitration of several polypeptides, including major targets with estimated molecular masses of 62, 68, and 77 kDa. Pretreatment with FGF-1 did not alter targets of peroxynitrite-mediated tyrosine nitration, but rather increased the total amount of this amino acid modification. Treatment with other reactive oxygen species failed to induce tyrosine nitration. Collectively, these efforts demonstrate that FGF-1 transiently renders primary fibroblasts more sensitive to peroxynitrite-induced apoptosis. In addition, results presented here predict a pivotal role for FGF-1 and peroxynitrite-induced cytotoxicity during the resolution of inflammation and repair processes in vivo.
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PMID:Acidic fibroblast growth factor enhances peroxynitrite-induced apoptosis in primary murine fibroblasts. 891 32