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)

Apoptosis in the androgen-sensitive Dunning R3327 PAP prostatic adenocarcinoma was studied during the post castration period of 14 days and compared with the ventral prostate. The mRNA expression of testosterone repressed prostatic message-2 and tissue-type plasminogen activator in the Dunning tumor and in the ventral prostate was analyzed by Northern blot experiments and immunohistochemical procedures. The degree of endonuclease-degraded genomic DNA was examined by gel electrophoresis. Apoptotic tumor epithelial cells were identified with in situ end labeling. Epithelial cells incorporating bromodeoxyuridine (BrdUrd) after castration in the ventral prostate and the Dunning tumors were localized with immunostaining. Androgen ablation resulted in an induction of testosterone repressed prostatic message-2 and tissue-type plasminogen activator transcripts in the normal prostate with a peak at approximately 2 to 5 days post castration. These transcript levels in the Dunning prostatic tumors did not show any induction during the same period. Immunohistochemical staining for sulfated glycoprotein-2 and tissue-type plasminogen activator confirmed this difference between the tumor tissue and the ventral prostate at the transcriptional level. The determination of DNA integrity showed similar results in that the degree of DNA fragmentation in the tumor was much lower than the initial and marked degradation of DNA in the ventral prostate. The number of in situ end-labeled epithelial tumor cells were not increased by castration. BrdUrd immunodetection showed that castration induced an initial increase in the number of BrdUrd-positive epithelial cells in the ventral prostate. In the tumors, castration resulted in a decrease in BrdUrd-positive epithelial cells. It was concluded that in the androgen-sensitive prostatic Dunning R3327 PAP adenocarcinoma, the biochemical cascade leading to apoptosis is not activated by androgen withdrawal, as in the ventral prostate.
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PMID:Castration induces apoptosis in the ventral prostate but not in an androgen-sensitive prostatic adenocarcinoma in the rat. 801 87

Thermal stress induces expression of a family of heat shock proteins which may regulate the synthesis of various cellular genes. We investigated the effect of heat shock on polyadenylation in Epstein-Barr Virus (EBV) negative and EBV transformed human Burkitt's lymphoma (BL) B-cell lines. Incubation of the BL B-cell line P3HR-1, carrying the defective EBV genome [EBV nuclear antigen-2 gene deletion] at 46 degrees C for 15 min increased nuclear poly(A) polymerase (PAP) activity. Thereafter, enzymatic activity declined and at 60 min it was reduced to about 50% of that observed in cells incubated at 37 degrees C. In contrast, no significant increase in PAP activity was observed at 15 min or thereafter in an EBV- BL cell line, ST-486, in response to elevated temperature. Furthermore, no heat shock mediated change in nuclear poly(A)-specific endonuclease activity was observed in either P3HR-1 or ST-486 cells suggesting a specific effect on PAP activity. However, thermal stress dependent increase in c-myc expression was detected only in P3HR-I cells. These results suggest an association between EBV transformation and enhanced expression of c-myc and PAP activity. To further determine the role of EBV, and EBV- BL cell line, BL-30, and BL-30 cells infected in vitro with a wild type strain of EBV, BL-30/B95-8, were investigated. BL-30/B-95-8, unlike the parental BL-30 cells, exhibited c-myc and PAP gene upregulation at 15 min but were downregulated at 60 min following exposure of cells to elevated temperatures. These results suggest that infection of human B-cells with EBV is associated with their ability to respond to thermal stress by increased PAP activity which may stabilize mRNA through enhanced polyadenylation.
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PMID:Differential effect of heat shock on RNA metabolism in human Burkitt's lymphoma B-cell lines. 855

Bacteriophage P4 immunity is controlled by a small stable RNA (CI RNA) that derives from the processing of primary transcripts. In previous works, we observed that the endonuclease RNase P is required for the maturation of CI RNA 5'-end; moreover, we found that polynucleotide phosphorylase (PNPase), a 3' to 5' RNA-degrading enzyme, is required for efficient 5'-end processing of CI RNA, suggesting that 3'-end degradation of the primary transcript might be involved in the production of proper RNase P substrates. Here, we demonstrate that another Escherichia coli nuclease, RNase E, would appear to be involved in this process. We found that transcripts of the P4 immunity region are modified by the post-transcriptional addition of short poly(A) tails and heteropolymeric tails with prevalence of A residues. Most oligoadenylated transcripts encompass the whole cI locus and are thus compatible as intermediates in the CI RNA maturation pathway. On the contrary, in a polynucleotide phosphorylase (PNPase)-defective host, adenylation occurred most frequently within cI, implying that such transcripts are targeted for degradation. We did not find polyadenylation in a pcnB mutant, suggesting that the pcnB-encoded polyadenyl polymerase I (PAP I) is the only enzyme responsible for modification of P4 immunity transcripts. Maturation of CI RNA 5'-end in such a mutant was impaired, further supporting the idea that processing of the 3'-end of primary transcripts is an important step for efficient maturation of CI RNA by RNase P.
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PMID:RNase E and polyadenyl polymerase I are involved in maturation of CI RNA, the P4 phage immunity factor. 1205 40