Figure 4.

Tg737 and Polaris expression and localization during sperm maturation. (A) Polaris expression was analyzed using the β-galactosidase reporter in the seminiferous tubules of the adult testis. Tg737 expression was detected in cells at the periphery and not in cells located near the tubule lumen. (B) In contrast to the β-galactosidase results, no Polaris expression could be detected in the cells of the periphery of the seminiferous tubules, but high levels were present in mature sperm within the seminiferous tubules. Polaris was concentrated on the same side of the hook in the mouse sperm in the region of the centriole (inset). Polaris could also be detected in the flagella axoneme. (C and D) A nearly identical staining pattern was seen for β-tubulin in the mature sperm; however, β-tubulin invariantly extended further up the sperm head (inset).