Tektin 3 is required for progressive sperm motility in mice.

Tektins are evolutionarily conserved flagellar (and ciliary) filamentous proteins present in the axoneme and peri-axonemal structures in diverse metazoan species. We have previously shown that tektin 3 (TEKT3) and tektin 4 (TEKT4) are male germ cell-enriched proteins, and that TEKT4 is essential for coordinated and progressive sperm motility in mice. Here we report that male mice null for TEKT3 produce sperm with reduced motility (47.2% motility) and forward progression, and increased flagellar structural bending defects. Male TEKT3-null mice however maintain normal fertility in two different genetic backgrounds tested, in contrast to TEKT4-null mice. Furthermore, male mice null for both TEKT3 and TEKT4 show subfertility on a mixed B6;129 genetic background, significantly different from either single knockouts, suggesting partial nonredundant roles for these two proteins in sperm physiology. Our results suggest that tektins are potential candidate genes for nonsyndromic asthenozoospermia in humans.