The spatial and temporal expression of Tekt1, a mouse tektin C homologue, during spermatogenesis suggest that it is involved in the development of the sperm tail basal body and axoneme

Tektins comprise a family of filament-forming proteins that are known to be coassembled with tubulins to form ciliary and flagellar microtubules. Rece ntly we described the sequence of the first mammalian tektin protein, Tekt1 (from mouse testis), which is most homologous with sea urchin tektin C. We have now investigated the temporal and spatial expression of Tekt1 during mouse male germ cell development. By in situ hybridization analysis TEKT1 R NA expression is detected in spermatocytes and in round spermatids in the m ouse testis, Immunofluorescence microscopy analysis with anti-Tekt1 antibod ies showed no distinct labeling of any subcellular structure in spermatocyt es, whereas in round spermatids anti-Tekt1 antibodies co-localize with anti -ANA antibodies to the centrosome. At a later stage, elongating spermatids display a larger area of anti-Tekt1 staining at their caudal ends; as sperm iogenesis proceeds, the anti-Tekt1 staining disappears. Together with other evidence, these results provide the first intraspecies evidence that Tekt1 is transiently associated with the centrosome, and indicates that Tekt1 is one of several tektins to participate in the nucleation of the flagellar a xoneme of mature spermatozoa, perhaps being required to assemble the basal body.