Fig. 3: Gdrd protein expresses during spermatid elongation and localizes to the growing axoneme.

a–a” Gdrd protein expression turns on during spermatid elongation. HA-tagged Gdrd protein expressed from a functional rescue construct in a gdrd mutant background is present weakly in mature spermatocytes and peaks in the early spermatids. Gdrd expression, however, is not present at the basal end of the testes, indicating that the protein is not present in individualizing or mature spermatids. b–b” Gdrd localizes to the growing axoneme during early stages of spermatid elongation. Inset in (b') shows that Gdrd localizes to the axoneme as well as a distally located punctate structure (arrow) that is reminiscent of proteins that localize to the ring centriole. c Gdrd localization in spermatid bundles with round nuclei (upper right) or canoe-shaped nuclei (lower left) becomes exclusive to the axonemes. d Spermatid bundles at the basal end of the testes with canoe-shaped nuclei express Gdrd, whereas later-staged spermatid bundles (with needle-shaped nuclei) lose Gdrd expression. e Distal ends of two elongating spermatid bundles. Gdrd localizes to both the growing axonemes and distally located punctate structures. The above images were derived from two independent replicates.