Functional analysis of germ line cells using gene manipulated mouse

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We have developed an easy and very efficient system to separate male and female embryos before implantation stage with non invasive manner. When male and female eggs prepared by this system were aggregated to produce sex chimera, the advantage of this system is the easiness of pointing out the sex of individual cells that form organs by observing the transgenically incorporated green fluorescent protein gene in X chromosome. By analyzing the genital organs in thus prepared sex chimeras, we have found many spermatogonia like cells of female origin in phenotypically male testes. The pattern of the genomic imprinting of these genes was found out to be male type in spite of their original sex was female.With the collaboration to Prof. Nakatsuji's group, it was also found out that these "female spermatogonia" cells entered meiosis in early stages of development However, on the other hand, some cells originated from female became huge cells like eggs in the testis of sex chimera animals, whi … More le the majority of the female cells developed into male type spermatogonia. The complexity of the sex differentiation of germ cells was elucidated by producing these sex chimera mice and simultaneously provided a tool to analyze the mechanism of male-female differentiation in germ line cells.Pig-a, an X-linked gene, is a key component of glycosylphosphatidylinositol (GPI) anchor biosynthesis based on the fact that lack of this gene causes deficiencies of hundreds of GPI-anchored proteins. Dr. Kondoh has produced a transgenic mouse line that expressed enhanced green fluorescent protein in GPI-anchored form and monitored GPI-anchor-positive cells in situ. It was found out that ACE has phospholipase activity other than the dipeptidyl-peptidase. It was suggested that testicular ACE is indispensable because it may release GPI anchored proteins from sperm surface to make fertile sperm. The results indicated that the necessity of re-evaluation of the involvement of ACE in reproductive biology. Less