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Xu G.,Institute of Nuclear Agricultural science | Lu H.,Institute of Nuclear Agricultural science | Wang L.,Institute of Nuclear Agricultural science | Chen H.,Institute of Nuclear Agricultural science | And 5 more authors.
DNA Repair | Year: 2010

The bacterium Deinococcus radiodurans can survive extremely high exposure to ionizing radiation. The repair mechanisms involved in this extraordinary ability are still being investigated. ddrB is one gene that is highly up-regulated after irradiation, and it has been proposed to be involved in RecA-independent repair in D. radiodurans. Here we cloned, expressed and characterized ddrB in order to define its roles in the radioresistance of D. radiodurans. DdrB preferentially binds to single-stranded DNA. Moreover, it interacts directly with single-stranded binding protein of D. radiodurans DrSSB, and stimulates single-stranded DNA annealing even in the presence of DrSSB. The post-irradiation DNA repair kinetics of a ddrB/recA double mutant were compared to ddrB and recA single mutants by pulsed-field gel electrophoresis (PFGE). DNA fragment rejoining in the ddrB/recA double mutant is severely compromised, suggesting that DdrB-mediated single-stranded annealing plays a critical role in the RecA-independent DNA repair of D. radiodurans. © 2010 Elsevier B.V. All rights reserved. Source

Lu H.,Zhejiang University | Xia W.,Zhejiang University | Chen H.,Zhejiang Institute of Microbiology | Yin L.,Zhejiang University | And 3 more authors.
Archives of Microbiology | Year: 2011

The extremely radioresistant bacterium Deinococcus radiodurans encodes a number of function-unknown genes, and some of them involve in the radioresistance. The radiation-inducible gene dr0171 has a recA-like expression pattern in the postirradiation recovery and was also supposed to encode a transcriptional regulator to contribute to the radioresistance. Here, we found that the EGFP-tagged DR0171 proteins gathered in the nucleoid regions after radiation. Further, we constructed a null mutant of dr0171 and found that the incapacitation of the dr0171 led to a signiWcant decline in resistance to -rays, UV radiation, and hydrogen peroxide and delayed genomic DNA reconstruction after radiation, indicating that this gene is involved in the postirradiation recovery. The microarray assays showed that the disruption of dr0171 does not lead to a signiWcant change in the transcriptional proWle of D. radiodurans under normal conditions, except after the stress of 6 kGy, radiation was applied. The transcript level of at least 153 genes decreased over twofold in the irradiated dr0171 mutant compared with those in the irradiated wild-type strain, indicating that DR0171 only functions after radiation damage. Taken together, the data presented here indicate that DR0171 serves as a regulator of the transcriptional response to radiation damage in D. radiodurans. © Springer-Verlag 2011. Source

Yang H.-J.,Zhejiang Cancer Hospital | Zheng Y.-B.,Zhejiang Cancer Hospital | Ji T.,Zhejiang Sci-Tech University | Ding X.-F.,Zhejiang Sci-Tech University | And 3 more authors.
Tumor Biology | Year: 2013

Integrin-linked kinase 1 (ILK1), a member of the serine/threonine kinases, has been demonstrated to be associated with numerous biological and pathological processes. However, the role of ILK1 in breast cancer has not been thoroughly elucidated. The purpose of this study was to assess ILK1 expression and to explore its contribution to breast cancer. The ILK1 mRNA expression was measured by real-time quantitative reverse transcriptase-polymerase chain reaction. In addition, ILK1 expression was analyzed by immunohistochemistry in 163 clinicopathologically characterized breast cancer cases. The relationship between ILK1 expression and clinicopathological features was analyzed by appropriate statistics. Kaplan-Meier analysis and Cox proportional hazard regression models were used to investigate the correlation between ILK1 expression and prognosis of breast cancer patients. The relative mRNA expression of ILK1 was significantly higher in breast cancer tissues than in adjacent noncancerous tissues (P < 0.001). In addition, ILK1 expression was significantly correlated with tumor size (P = 0.016), grade (P = 0.024), stage (P = 0.029), lymph node metastases (P = 0.007), and estrogen receptor status (P = 0.002). Kaplan-Meier analysis indicated that patients with high ILK1 expression had poor overall survival (P < 0.001). Multivariate analysis showed that high ILK1 expression was an independent predictor of overall survival. In conclusion, our data suggest for the first time that the increased expression of ILK1 in breast cancer is associated significantly with aggressive progression and poor prognosis. ILK1 may be an important molecular marker for predicting the carcinogenesis, progression, and prognosis of breast cancer. © 2013 International Society of Oncology and BioMarkers (ISOBM). Source

Hu W.,Zhejiang University | Wang T.,Zhejiang Institute of Microbiology | Yang Y.,Brigham and Womens Hospital | Zheng S.,Zhejiang University
Biochemical and Biophysical Research Communications | Year: 2014

miRNA is increasingly being recognized as a key regulator of metabolism in animals. A wealth of evidence has suggested that miRNA mainly binds 3′ UTR of mRNA and modulates the cell activities via repressing the mRNA translation. However, as the translation initiates at 5′ UTR, cis elements like upstream open reading frame (uORF) resided in 5′ UTR may also affect the translation efficiency or elongation. In this study, we performed a systematic analysis of miRNA responsive elements (MREs) and uORF of the same transcript in three model organisms (human, mouse, and Drosophila). Intriguingly, we found that the 3′ UTR length grew with the complexity of species (human > mouse > Drosophila), in sharp contrast with the invariability of 5′ UTR. Additionally, MRE number correlated well with the 3′ UTR length, while uORF number showed a weak correlation with the 5′ UTR length. Further, we found that human genes with conserved peptide upstream open reading frame (CPuORF) tend to have more MREs and lower evolutionary rates, which provides new insights into the correlation between UTR properties and translational control in animals. © 2014 Elsevier Inc. All rights reserved. Source

Lu H.,Zhejiang University | Chen H.,Zhejiang Institute of Microbiology | Xu G.,Zhejiang University | Shah A.M.-U.-H.,Zhejiang University | Hua Y.,Zhejiang University
DNA Repair | Year: 2012

The extremely radioresistant bacterium. Deinococcus radiodurans possesses a rapid and efficient but poorly known DNA damage response mechanism that mobilizes one-third of its genome to survive lethal radiation damage. Deinococcal PprI serves as a general switch to regulate the expression of dozens of proteins from different pathways after radiation, including the DNA repair proteins RecA, PprA and SSB. However, the underlying mechanism is poorly understood. In this study, we analyzed the dynamic alteration in global transcriptional profiles in wildtype and. pprI mutant strains by combining microarrays and time-course sampling. We found that PprI up-regulated transcription of at least 210 genes after radiation, including 21 DNA repair and replication-related genes. We purified PprI and a helix-turn-helix (HTH) domain mutant and found that PprI specifically bound to the promoters of. recA and. pprA in vitro but did not bind nonspecific double-strand DNA. Chromatin immunoprecipitation (ChIP) assays confirmed that PprI specifically interacted with the promoter DNA of. recA and. pprA after radiation. Finally, we showed that a DNA-binding activity-deficient pprI mutant only partially restored resistance of the. pprI mutant strain to γ radiation, UV radiation, and mitomycin C. Taken together, these results indicate that DNA-binding activity is essential for PprI to program the DNA repair process and cellular survival of. D. radiodurans in response to radiation damage. © 2011 Elsevier B.V.. Source

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