Detection of stress-induced 5′tRNA halves by poly(A) tailed-RNase H digestion-RT-PCR / 军事医学

Objective To develop a simple and quick method for detection of stress-induced 5′transfer RNA( tRNA) halves.Methods Total RNA purified from stress induced cells was polyadenylated by poly( A) polymerase, and then degen-erate DNA probes were used to hybridize with 3′tRNA-halves of intact tRNAs,while RNase H specifically degraded the 3′tRNA-halves strand in tRNA-DNA probes hybrids.Using the RNase H digestion total RNA as templates, complementary DNA( cDNA) was synthesized by oligo ( dT) n-anchored primers.The primer of 5′tRNA halves and anchored-primer were used to amplify 5′tRNA halves by PCR.Results The results showed that the method of poly ( A )-tailed-RNase H digestion-RT-PCR could be successfully used to detect stress-induced 5′tRNA halves.Conclusion A simple and quick method for detection of 5′tRNA halves has been established,which is a user-friendly tool for 5′tRNA halves detection and function research.

Effect of poly(ADP - ribose) polymerase on the response of guinea pig tracheas induced by peroxynitrite in vitro / 中国病理生理杂志

AIM and METHODS: to elucidater the effect of poly(ADP-ribose) polymerase(PARP) on tracheal hyperreactivity of guinea - pig induced by peroxynitrite, the responses of guinea pig tracheas to histamine af- ter incubation with peroxynitrite in the absence and presence of 3 - aminobenzamide(3 - AB), a highly selective inhibitor for PARP, were observed in vitro. RESULTS: The exposure of tracheal strips to peroxynitrite led to epithelial damage and hyperreacitivity to histamine, both of which were reversed by 3 - AB(l mmol/L or 5mmol/L), whereas incubation of tracheal strips with 3 - AB(5 mmol/L) had no effect on the reponses. CONCLUSION:PARP is involved in the epithelial damage and hyperreactivity of guinea - pig tracheas induced by peroxynitrite. The results suggested that inhibition of excessive activation of PARP may represent a novel strategy for the prevention and therapy of airway hyperreactivity in asthma.

Hormonal regulation of poly(A) polymerase in the testis of rat.

Polyadenylation of mRNA is a post-transcriptional phenomenon and is catalysed by both nuclear and cytoplasmic poly(A) polymerases. In rat testis the specific activity of cytoplasmic poly(A) polymerase increased with age reaching a peak value in 80 days. After this time the activity was maintained at a slightly lower level for the next 280 days. Follicle stimulating hormone, luteinizing hormone, human chorionic gonadotropin, pregnant mare serum gonadotropin and a gonadotropin releasing hormone analogue significantly increased the enzyme activity in immature rat testis. These results show that testicular poly(A) polymerase was probably under the influence of gonadotropic hormones.

Inhibitory effect of gonadotropin releasing hormone in the uterus of rat.

Estradiol-induced incorporation of radioactive uridine and leucine into the uterus of rat was inhibited by simultaneous treatment with an analogue of gonadotropin releasing hormone. The inhibitory action of gonadotropin releasing hormone was not mediated through modulation of estradiol receptor content. However, estradiol-induced increase in the level of poly(A) polymerase was inhibited by gonadotropin releasing hormone analogue, indicating that the inhibitory effect might involve post-transcriptional phenomenon.