Ppp2ca Gene Inactivation Affect Spermatogenesis In Male Mice And Hippocampus Specific Knockout Construct And Phenotypic Dicer1 Protein In Mice

Objective:Spermatogenesis is a spatially and temporally regulated multi-step process, consisting of many mechanisms to control the differentiation of several cell types from PGCs to mature sperm, such as meiosis and mitosis. Protein phosphatase2A (PP2A) is a ubiquitous serine/threonine phosphatase which can combine with Shugoshin protein to regulate the process of mitosis and meiosis. The experiment intends to research the function of Ppp2ca in spermatogenesis by generating the Ppp2ca conditional knockout mice and inactivation of Ppp2ca in mice testes.Method:Generated the Ppp2ca conditional knockout mice, and crossed it with transgenic mice Ddx4-Cre to get the mutant mice with Ppp2ca deletion as early as in germ cells at E12.5. The impact of Ppp2ca deficient in germ cells on spermatogenesis was assessed by performing the assays of western, slices of testicular tissue, sperm smear and flow cytometry experiment etc.Results:The mice with the genotype of Ppp2caflox/flox; Ddx4-Cre were obtained. The Ppp2ca knockout efficiency was assessed by western and genomic PCR. The mouse testis weight and tissue sections were detected at4weeks,5weeks and8weeks. The size and weight of testes in Ppp2ca mutant mice were more than half decreased. The H&E staining of testes sections showed the mutant tubules contained a large number of vacuolation structures, chromatin agglutination in the germ cells were abnormal, and there was a lack of normal spermatozoa in the testes. A large number of cells with abnormal DNA content were detected in mutant mice when performing flow cytometry experiment. Compared with control, the male mutant mouse were infertility by Fertility testing.Conclusion:Spermatogenesis was mostly arrested in the germ cells when Ppp2ca was inactivated at E12.5, a large number of vacuolation structures were found in the mutant tubules, and the size and weight of testes in Ppp2ca mutant mice were more than half decreased, which culminated in the sterility of male mice. These indicated that Ppp2ca was indispensable in the process of spennatogenesis. Objective:Dicerl(RNAase III enzyme) was knocked out in a spatial or temporal-specific manner in the hippocampus, and preliminary observations were conducted to find out the role Dicerl played in the growth and development of the mouse hippocampus.Methods:The Frizzled9-CreERTM mice in which Cre enzyme was exclusively detected in the hippocampus bred with Dicerl (flox/flox) mouse to obtain Dicer1(flox/+);Frizzled9-CreERTM mice, then bred with the Dicerl (flox/flox) mouse again to obtain Dicerl (flox/flox);Frizzled9-CreERTM mice. Using tamoxifen (TM) to induce the expression of Cre enzyme, Dicerl was specifically knocked out in the hippocampus in mice then observed the phenotype of mice.Results:The TM induced Dicerl Conditional Null Allele in the Hippocampus almost died about40days after birth; the CA3region in the hippocampus was thinner. It probably caused by the lack of Dicerl enzyme in the hippocampus.Conclusion:Dicerl plays an important role in the production of miRNA. Dicerl Conditional Null Allele in the Hippocampus cannot develop and grow normally and prone to death.