ABSTRACT
Ubiquitinating enzyme damaged-DNA binding protein 2 (DDB2) is a rind of DDB1 and CUL4-associated factors (DCAF), and identifies belonging to the family of ubiquitinating E3 enzymes. DDB2 combines with CUL4-DDB1 to form the ubiquitin ligase complex, and identifies targets protein substrate specificity to make the substrate ubiquitin and degradation. It affects the development of tumors through various pathways, such as DNA damage repair, cell cycle regulation and apoptosis, cell invasion and metastasis, cell premature senescence, cell proliferation and cancer stem cell population. This paper reviews the progress of the relationship between DDB2 and the development, treatment and prognosis judgment of tumors.
ABSTRACT
DNA found at the scene of a crime is often damaged and degraded to small fragments and remained in low quantity. Therefore, there are some difficulties in forensic STR typing of these DNA samples. In this study, to overcome these limitations as different approach, we applied repairing enzyme to damaged DNA. The efficacy of a repair enzyme system (PreCR Repair Mix) was evaluated by using several types of artificially damaged and naturally damaged DNA. The results showed that autosomal STR amplification produced increased yield in the DNA damaged by UV irradiation, oxidation, or acid/heat, and DNA from dried blood spot and dried saliva spot by treatment of a repair enzyme, but not in DNA extracted from old skeletal remains. In conclusion, a repair enzyme will be efficiently applied to forensic samples which were damaged by UV irradiation, oxidation, and acid/heat.
Subject(s)
Crime , DNA , SalivaABSTRACT
Retrieval of ancient DNA (aDNA) sequences from organism remains provide direct view of their evolutionary history. However, researches on aDNA have suffered from lots of technical problems. Specifically, discredited sequences were generated from damaged aDNA templates, and expensive and time-consuming methods were employed. Here, a method which could recover the endogenous aDNA as well as to reduce the cost and research period is described. This is achieved by improving the ancient DNA extraction method of isopropanol precipitation, and reevaluating the method of PCR after N-glycosylase (UNG) treatment, which could remove the damaged DNA from the aDNA extract. The efficiency of these methods were tested by comparing with traditional methods using ancient specimens of pig teeth aged between 4 300 years before present (BP) and 3 900 BP. The results showed that: firstly, the extraction efficiency of the improved method of isopropanol precipitation and current method with silica-based spin column were all 60%. Furthermore, the research period at least could be reduced by half with the application of the improved methods and the cost to 1/10 of the current method. Secondly, sequences obtained through the method of PCR after UNG treatment were 100% authentic. In contrast, 66%～ 88% sequences were authentic based on the results obtained with the method of multiple PCRs without UNG treatment. And the research cost and period needed by the method with UNG treatment were only half of the later one. These results demonstrate that the improved extraction method of isopropanol precipitation combined with the method of PCR after UNG treatment could increase the success rate of authentic DNA amplified and at least reduce the research cost and period by half. Therefore, this method can be applied in the large-scale detection of ancient specimens.