Astral Microtubules Are Dispensable for Pavarotti Localization During Drosophila Spermatogonial Mitoses.

We analysed here the dynamic of the kinesin-like Pavarotti (Pav) during male gametogenesis of wild-type and Sas4 mutant flies. Pav localizes to the equatorial region and the inner central spindle of late anaphase wild-type spermatogonia and displays a strong concentration at the midbody during late telophase. At metaphase of the first meiotic division, Pav shows widespread localization on the equatorial region of the spermatocytes.

Axonemal tubules in the distal sperm tail of Wolbachia-infected Drosophila simulans males contain ring-like intraluminal structures that persist after axoneme fragmentation.

Wolbachia are obligate intracellular alphaproteobacteria that enhance their spreading by altering the reproductive mechanisms of several invertebrates. Among the reproductive alterations, Wolbachia also causes cytoplasmic incompatibility that leads to embryo death when infected males are crossed with uninfected females, thus selecting infected females. However, the presence of Wolbachia has important fitness costs and infected Drosophila simulans males produce less sperm than their uninfected counterparts.

The cilium like region of the Drosophila bifurca spermatocyte: Elongation of a giant axoneme without intraflagellar transport.

The growth of the ciliary axonemes mainly depends on the evolutionary conserved intraflagellar transport (IFT) machinery. However, insect spermatocytes are characterized by cilium-like regions (CLRs) that elongate in the absence of IFT. It is generally believed that the dynamics of these structures relies on the free diffusion of soluble tubulin from the cytoplasm.

Induces Structural Defects Harmful to Riverside Spermiogenesis.

The relationship between cytoplasmic incompatibility and the obligate intracellular alphaproteobacteria has for a long time been reported. Although the molecular mechanisms responsible for this reproductive alteration are beginning to be understood, the effects of on germ cell structure and dynamics have not yet been fully investigated. We report here that the presence of in infected cysts of elongating spermatids is associated with major structural defects that become more evident in mature sperm.