Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.7.7 (DNA polymerase)
 17,007 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The protective effect of Mr 70,000 heat shock protein (HSP-70) during thermotolerance has been previously observed. However, it is not known what cellular processes or components may be protected by this protein during the tolerance state. In the studies reported here, the protective effects of purified HSP-70, the nonspecific heat-stable proteins fetuin and trypsin inhibitor (ovomucoid), and other proteins and agents such as bovine serum albumin, D2O, or glycerol on protein and DNA synthesis during heating were investigated in vitro. In vitro protein synthesis at 30, 40, and 42 degrees C was measured by globin mRNA translation. Protein synthesis was inhibited 40 to 70% when incubated for 60 min at 40 and 42 degrees C. However, protein synthesis was protected when either fetuin or ovomucoid was present during protein synthesis at elevated temperatures. The protection was concentration dependent. The HSP-70 purified from Chinese hamster (HA-1) cells was also able to confer protection to the translation system, but at much lower concentrations than either fetuin or ovomucoid. Other proteins, such as bovine serum albumin, or other agents, such as D2O or glycerol which are known protectors of cellular survival during heating, did not protect the translation system. Similar experiments were performed with DNA synthesis in vitro. Purified DNA polymerase alpha was added to the activated calf thymus DNA in an in vitro replication system. A temperature of 46 degrees C for 60 min inhibited replication by 40%. Addition of heat-stable proteins, purified HSP-70, bovine serum albumin, D2O, or glycerol did not confer protection to the replication system. These studies provide new evidence that HSP-70 may confer protection to a component of the protein synthesis machinery during thermotolerance.
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PMID:Effects of heat shock proteins (Mr 70,000) on protein and DNA synthesis at elevated temperatures in vitro. 246 56

Effects of various nucleoside analogues on X-ray-induced-PLD recovery (PLDR) were examined in plateau phase Chinese hamster HA-1 cells. Among the chemicals tested, 3'-dA (3'-deoxyadenosine) and ara-A (9-beta-D-arabinofuranosyladenine) were most potent inhibitors of PLDR at their slightly toxic doses. N6-butyryl-3'-dA and 3'-dG (3'-deoxyguanosine) were the most effective in suppressing PLDR at non-toxic doses. A specific inhibitor of DNA polymerase beta, 2', 3'-ddT (dideoxythymidine) was intermediately effective. However, possibly due to the lower intracellular incorporation or phosphorylation, 3'-deoxy-pyrimidine analogues and formycin B were less or non-effective. The enhancement of antitumor effect of cyclophosphamide by ara-A and 3'-dG was observed in SCC VII tumors in vivo. The involvement of DSB (or chromosome aberration) and SSB as well as base damage or crosslinks in PLD is suggested, since recently they have been shown not to be rejoined when treated with various agents such as hyperthermia and ara-A.
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PMID:PLDR inhibitors: their biological and clinical implications. 660 38