We have shown by both light and confocal microscopy studies that the murine SPNR protein, which is associated with manchette microtubules in wild-type testes, is also present on the abnormal manchettes and microtubule aggregates found in the testes of four mouse mutants: azh, hop, tw8, and tw2. We never found localization of SPNR to be independent of microtubules in the testis. If cytoplasmic microtubules are present, SPNR is associated with them, regardless of the type of manchette structure present. antibiotic levaquin
In cases in which we saw an overproliferation of microtubules, we also saw an abundance of SPNR, suggesting that the expression or stability of SPNR is linked to the concentration of manchette microtubules. Variations in tubulin concentration along the length of the manchette, as in tw8 testes, is reflected by the same variation in SPNR staining. When microtubules are degraded in the degenerating spermatids of hop and tw2 testes, SPNR staining overlaps with that of free tubulin. We conclude that SPNR is tightly associated with manchette microtubules.