Regulation of blood-testis barrier assembly in vivo by germ cells

The assembly of the blood-testis barrier (BTB) during postnatal development is crucial to support meiosis. However, the role of germcells in BTB assembly remains unclear. Herein, Kit(W)/Kit(WV) micewere used as a study model. These mice were infertile, failing to establish a functional BTB to support meiosis due to c-Kit mutation. Tra nsplantation of undifferentiated spermatogonia derived from normal mice into the testis of Kit(W)/Kit(WV) mice triggered functional BTB assembly, displaying cyclic remodeling during the epithelial cycle. Also, transplanted germ cells were capable of inducing Leydig cell testosterone production, which could enhance the expression of integral membrane protein claudin 3 in Sertoli cells. Early spermatocytes were shown to play a vital role in directing BTB assembly by expressing claudin 3, which likely created a transient adhesion structure to mediate BTB and cytoskeleton assembly in adjacent Sertoli cells. In summary, the positive modulation of germcells on somatic cell function provides useful information regarding somatic-germ cell interactions.