The Influence Of Mutant P53-p53^N236S On Mouse Embryonic Development In The Background Of Wrn-null

Embryonic development is a special biological process in living things. In essence, embryonic development starts from the ordered expression of amphicytula genome. It not only contains cell multiplication, differentiation and migration, but also contains germ layer formation, histogenesis and organofaction. At last, it will form a complete organism. Besides multiplication and differentiation, embryonic development relates to apoptosis. Research shows that a multitude of oncogenes and tumor-suppressing genes involve in the regulation of embryonic development.As a tumor-inhibiting factor, p53 plays an extremely important role in embryonic development. In some stage of embryonic development of mice and human, p53 expresses highly in some tissues and organs. Knock out some biological factor which can regulate p53-such as MDM2-will cause mice embryonic lethal. p53 is also important to neural development. Research has shown that p53-null and some mutation of p53 can cause neural tube defects (NTDs).As a member of RecQ DNA helicase family, Wrn keeps the stability of genome by keeping the stability of telomere. By participating in S phase checkpoint, Wrn can regulate the cell multiplication. If Wrn was induced mutation or knocked out, it may lead to the Werner Syndrome (WS). Now we don’t know how it works between p53 and Wrn in embryonic development.p53N236S (hereinafter referred to as p53s) is a missense mutation of p53 which was found by the Laboratory of molecular genetics of aging and tumor of Medical college of KMUST. The p53s has been confirmed potential of oncogene. In order to further study the relationship between p53s and Mice, the laboratory builds the p53s/s mouse model which comes from the C57BL/6 strain. And then we have got the Wrn-/-p53s/s mouse model by hybridizing p53s/s mouse with Wrn-/-C57BL/6 mouse. In preliminary study, we found that the number of p53s/s female mouse and Wrn-/-p53s/s female mouse was much less than expectation. The Wrn-/-p53s/s mouse which comes from Wrn-/-p53s/s ((?))×Wrn-/-p53s/+(♀) was much less than Wrn-/-p53s+s mouse, too. It means that some of th p53s/s and Wrn-/-p53s/s mouse embryos were dead in embryonic development.So our study planned using the p53s/ sand Wrn-/-p53s/s mouse as the experimental animal model. We applied the technique of PCR, H.E staining, immunohistochemical method and detection of apoptosis. We intended to illuminate the relationship between p53N236s and embryonic development on condition that Wrn was knocked out. We hoped we can expound the new function of p53s in embryonic development and we could key for the study of p53 and Wrn in embryonic development.By the study, we found that most of p53s/s and Wrn-/-p53s/s female mice E11.5 embryos had NTDs-exencephaly and spina bifida. Exencephaly could translate anencephaly after El 8.5 and finally the anencephaly embryos died. The incidence of NTDs of p53s/s and Wrn-/-p53s/s female mice embryos were obvious more than Homozygote p53s male embryos and heterozygote embryos. The result of NTDs embryos vertical plane H.E staining showed that the brains of NTDs embryos were disorder, and the scalps of NTDs embryos were lost. In cellular level, we found that NSCs in the brains of NTDs p53s/s and Wrn-/-p53s/s female embryos were in high speed of multiplication and apoptosis. The result of NTDs embryos transverse plane H.E staining showed that the neural tubes in p53s/s female embryos stagnated differentiation. Besides, our study showed that Wrn-null made mice embryos died easily than wild type. The result of NTDs embryos transverse plane H.E staining showed that the speed of the neural tubes differentiation of Wrn-/-p53s/s female were faster than p53s/s. Wrn-/-p53s/s female embryos died much earlier than any other genotypes and sexes.In summary, we found that homozygote p53N236s made female mice embryos NTDs and die in the later stage of development. Homozygote p53N236S could inhibit normal neural development in female mice embryos. Wrn-null made mice embryos died easily than wild type. Wrn-null and homozygote p53N236S may have potential interaction in mice embryonic development. Our study illuminated the new mechanism of p53 and Wrn in embryonic development preliminarily and provided reference for resaerching the relationhip of p53 and embryonic neural development.