Male gametogenesis without centrioles.
The orientation of the mitotic spindle plays a central role in specifying stem cell-renewal by enabling interaction of the daughter cells with external cues: the daughter cell closest to the hub region is instructed to self-renew, whereas the distal one starts to differentiate. Here, we have analyzed male gametogenesis in DSas-4 Drosophila mutants and we have reported that spindle alignment and asymmetric divisions are properly executed in male germline stem cells that lack centrioles. Spermatogonial divisions also correctly proceed in the absence of centrioles, giving rise to cysts of 16 primary spermatocytes. By contrast, abnormal meiotic spindles assemble in primary spermatocytes. These results point to different requirements for centrioles during male gametogenesis of Drosophila. Spindle formation during germ cell mitosis may be successfully supported by an acentrosomal pathway that is inadequate to warrant the proper execution of meiosis.
University of Siena, Department of Evolutionary Biology, Via A. Moro 2, I-53100 Siena, Italy.
Maria Giovanna
MG
Riparbelli
Giuliano
G
Callaini
D000818:Animals; D016764:Cell Polarity / Q000502:physiology*; D002502:Centrioles / Q000502:physiology*; D004330:Drosophila / Q000502:physiology*; D029721:Drosophila Proteins / Q000235:genetics; D005718:Gametogenesis / Q000502:physiology*; D005854:Germ Cells / Q000166:cytology*; D008297:Male; D046529:Microscopy, Electron, Transmission; D008856:Microscopy, Fluorescence; D008869:Microtubule-Associated Proteins; D008870:Microtubules / Q000502:physiology; D013094:Spermatozoa / Q000166:cytology*; D008941:Spindle Apparatus / Q000502:physiology*; D013234:Stem Cells / Q000166:cytology*; D013737:Testis / Q000648:ultrastructure
D029721:Drosophila Proteins; D008869:Microtubule-Associated Proteins; C522063:Sas-4 protein, Drosophila