An increasing data indicates that altered microRNAs(miRNAs)participate in the radiation-induced DNA damage response.However,a correlation of mRNA and miRNA profiles across the entire genome and in response to irradiat...An increasing data indicates that altered microRNAs(miRNAs)participate in the radiation-induced DNA damage response.However,a correlation of mRNA and miRNA profiles across the entire genome and in response to irradiation has not been thoroughly assessed.We analyzed miRNA microarray data collected from HeLa cells after ionizing radiation(IR),quantified the expression profiles of mRNAs and performed comparative analysis of the data sets using target prediction algorithms,Gene Ontology(GO)analysis,pathway analysis,and gene network construction.The results showed that the altered miRNAs were involved in regulation of various cellular functions.miRNA-gene network analyses revealed that miR-186,miR-106b,miR-15a/b,CCND1and CDK6 played vital role in the cellular radiation response.Using qRT-PCR,we confirmed that twenty-two miRNAs showed differential expression in HeLa cells treated with IR and some of these miRNAs affected cell cycle progression.This study demonstrated that miRNAs influence gene expression in the entire genome during the cellular radiation response and suggested vital pathways for further research.展开更多
Ionizing radiation (IR) causes severe cellular damage both directly and indirectly and disrupts RNA integrity. RNA strand breaks are the most frequent type of damage caused by IR. RNA damage is involved in the develop...Ionizing radiation (IR) causes severe cellular damage both directly and indirectly and disrupts RNA integrity. RNA strand breaks are the most frequent type of damage caused by IR. RNA damage is involved in the development of degenerative diseases, including Alzheimer’s disease and Parkinson’s disease. However, the mechanism of mRNA damage and any resulting pathophysiological outcomes are poorly understood. This is partly because there is a lack of sensitive tools to monitor damage randomly occurring in RNA, especially RNA strand break damage in a given RNA. In this work, a method using the reverse transcription polymerase chain reaction (RT-PCR) after poly(A) addition to 3′-end of RNA to determine RNA strand break damage in a specific RNA by poly(A) polymerase has been developed. The levels of damage in specific mRNAs, including ABL1, TP53, GADD45A and ATR from IR-treated HeLa cells were examined. Strand breaks were detected in all mRNAs examined. The study provides a novel and sensitive method based on 3 -end poly(A)-tailing RT-PCR to monitor RNA strand break damage.展开更多
The cyclin-dependent kinase inhibitor p21 WAF1/Cip1 is a critical cell cycle regulator which translocates into the nucleus to participate in DNA repair during DNA damage responses. In the present study, we showed that...The cyclin-dependent kinase inhibitor p21 WAF1/Cip1 is a critical cell cycle regulator which translocates into the nucleus to participate in DNA repair during DNA damage responses. In the present study, we showed that the tumor suppressor, promyelocytic leukemia protein (PML) contributes to the up-regulation of p21 in a p53-independent pathway. Knock-down of PML in p53-null H1299 and HCT 116 (p53 –/– ) tumor cells by specific siRNA resulted in down-regulation of p21 protein expression, inhibition of -irradiation-induced p21 up-regulation, and a decrease in p21 protein half-life. In PML knockdown H1299 cells, the down-regulation of p21 protein expression was reversed by MG132 treatment indicating that the proteasomal degradation of p21 protein was increased. Thus, PML positively regulates p21 expression by inhibiting proteasome-mediated proteolysis. Knockdown of PML decreased the repair of -irradiation-induced double strand breaks (DSBs) as indicated by the delayed disappearance of -H2AX foci and a decreased association between p21 and proliferating cell nuclear antigen (PCNA). Over-expression of p21 significantly restored the delayed DSB repair function. Taken together, these data provide evidence for a p53-independent functional relationship between PML and p21 in -irradiation-induced DNA damage responses, and identify PML as a positive post-translational regulator of p21 in p53-deficient tumor cells.展开更多
By means of comet assay, a study of kinetics curve of DNA damage repair in irradiated SX-9 cells that came from mouse breast cancer proceeded. It was found that while the initial DNA damages had nearly been repaired, ...By means of comet assay, a study of kinetics curve of DNA damage repair in irradiated SX-9 cells that came from mouse breast cancer proceeded. It was found that while the initial DNA damages had nearly been repaired, DNA damages arose for the second time, then they were repaired again. As a result, a phenomenon of "secondary damage" was found during the repair of DNA damages in irradiated SX-9 cells. Further research illuminated that 3-aminobenzamide (3AB), which is an inhibitor of poly (ADP-ribose) polymerase, could change the proceeding of "secondary damage". For this reason it is possible that there exists some inner relationship between the phenomenon of "secondary damage" and the function of poly(ADP-ribose) polymerase.展开更多
基金supported by the National Basic Research Program of China(2010CB912801 and 2007CB914601)the National Natural Science Foundation of China(31170713)the Beijing Municipal Natural Science Foundation(5112029)
文摘An increasing data indicates that altered microRNAs(miRNAs)participate in the radiation-induced DNA damage response.However,a correlation of mRNA and miRNA profiles across the entire genome and in response to irradiation has not been thoroughly assessed.We analyzed miRNA microarray data collected from HeLa cells after ionizing radiation(IR),quantified the expression profiles of mRNAs and performed comparative analysis of the data sets using target prediction algorithms,Gene Ontology(GO)analysis,pathway analysis,and gene network construction.The results showed that the altered miRNAs were involved in regulation of various cellular functions.miRNA-gene network analyses revealed that miR-186,miR-106b,miR-15a/b,CCND1and CDK6 played vital role in the cellular radiation response.Using qRT-PCR,we confirmed that twenty-two miRNAs showed differential expression in HeLa cells treated with IR and some of these miRNAs affected cell cycle progression.This study demonstrated that miRNAs influence gene expression in the entire genome during the cellular radiation response and suggested vital pathways for further research.
基金supported by the National Basic Research Program of China (2007CB914601, 2010CB912801)Beijing Municipal Natural Science Foundation (5112029)
文摘Ionizing radiation (IR) causes severe cellular damage both directly and indirectly and disrupts RNA integrity. RNA strand breaks are the most frequent type of damage caused by IR. RNA damage is involved in the development of degenerative diseases, including Alzheimer’s disease and Parkinson’s disease. However, the mechanism of mRNA damage and any resulting pathophysiological outcomes are poorly understood. This is partly because there is a lack of sensitive tools to monitor damage randomly occurring in RNA, especially RNA strand break damage in a given RNA. In this work, a method using the reverse transcription polymerase chain reaction (RT-PCR) after poly(A) addition to 3′-end of RNA to determine RNA strand break damage in a specific RNA by poly(A) polymerase has been developed. The levels of damage in specific mRNAs, including ABL1, TP53, GADD45A and ATR from IR-treated HeLa cells were examined. Strand breaks were detected in all mRNAs examined. The study provides a novel and sensitive method based on 3 -end poly(A)-tailing RT-PCR to monitor RNA strand break damage.
基金supported by the National Basic Research Program of China (2007CB914604)the National Natural Science Foundation of China (30900276, 30970683, 30600162)
文摘The cyclin-dependent kinase inhibitor p21 WAF1/Cip1 is a critical cell cycle regulator which translocates into the nucleus to participate in DNA repair during DNA damage responses. In the present study, we showed that the tumor suppressor, promyelocytic leukemia protein (PML) contributes to the up-regulation of p21 in a p53-independent pathway. Knock-down of PML in p53-null H1299 and HCT 116 (p53 –/– ) tumor cells by specific siRNA resulted in down-regulation of p21 protein expression, inhibition of -irradiation-induced p21 up-regulation, and a decrease in p21 protein half-life. In PML knockdown H1299 cells, the down-regulation of p21 protein expression was reversed by MG132 treatment indicating that the proteasomal degradation of p21 protein was increased. Thus, PML positively regulates p21 expression by inhibiting proteasome-mediated proteolysis. Knockdown of PML decreased the repair of -irradiation-induced double strand breaks (DSBs) as indicated by the delayed disappearance of -H2AX foci and a decreased association between p21 and proliferating cell nuclear antigen (PCNA). Over-expression of p21 significantly restored the delayed DSB repair function. Taken together, these data provide evidence for a p53-independent functional relationship between PML and p21 in -irradiation-induced DNA damage responses, and identify PML as a positive post-translational regulator of p21 in p53-deficient tumor cells.
文摘By means of comet assay, a study of kinetics curve of DNA damage repair in irradiated SX-9 cells that came from mouse breast cancer proceeded. It was found that while the initial DNA damages had nearly been repaired, DNA damages arose for the second time, then they were repaired again. As a result, a phenomenon of "secondary damage" was found during the repair of DNA damages in irradiated SX-9 cells. Further research illuminated that 3-aminobenzamide (3AB), which is an inhibitor of poly (ADP-ribose) polymerase, could change the proceeding of "secondary damage". For this reason it is possible that there exists some inner relationship between the phenomenon of "secondary damage" and the function of poly(ADP-ribose) polymerase.
