Of Sry Nucleic Acid Immunization Of Sex Determination In Mice

In mammal, sex development can be divided into two steps. The first step is sex determination—it is the consequence of the interactions of many genes which can cause differentiation of gonads as testis or ovary; the second step is sex differentiation—it relies on hormones secreted from differentiated gonads, which ultimately results in the establishment of phenotypic sex, male or female. Sex determination is the premise of sex differentiation and following development. The sex determination is started by gene SRY/Sry, which happens between 10.5 d.p.c. and 12.5 d.p.c, and SRY/Sry synchronously presents at this time. Sex determination is a brief but complicated process. All relative researches have shown the key role of SRY/Sry in sex determination in mammal animals.Now several laboratories have got XX male reversal mice by transgening Sry . Our study has illuminated that XX embryo could be reversely developed into male individual by transgening Sry by sperms-mediated transgenic technique. Some other researches also got XY female mice by knocking out Sry gene or making a point mutation in Sry HMG box. The present research, for the first time, is designed to suppress the pathway of Sry during embryo sex determination through DNA immunizing and has got XY female reversal mice .Firstly, the eukaryotic expression Plasmid pCR3.1-Sry was recombined and largely extracted as nucleic acid vaccine. Next, this vaccine at certain concentration and purity was injected into the leg muscle of mature female mice. Response to the DNA vaccine, the immunized mice will produce anti-SRY antibody which can pass placenta barrier and interacted with SRY protein expressed in their embryo. Anti-SRY antibody could effectively recognize the SRY protein in embryo, consequently restrain the function of SRY, finally shut off the differentiation of undifferentiated gonads into testis and therefore, XY female reversal mice appeared. In our research, after immunizing, 15 pregnant female mice gave birth in all. The number of the total offspring is 97, and sex ratio ( (?): (?)) shift from normal 1:1 into 1: 1.11 (p<0.05). To amplify Sry gene of the offspring that phenotypic sex are female with PCR, the results demonstrate that XY female mice have be successfully achieved in this research. Among the reversal mice, some have normal sexual cycle and have be pregnant successfully in mating trial. As the sham immunization, we injected empty pCR3.1 plasmid (without Sry segment) at the same concentration, thus, sex ratio of offspring is normal (1:1) and all the PCR results from...