A transient microtubule-based structure uncovers a new intrinsic asymmetry between the mother centrioles in the early Drosophila spermatocytes.

Abstract

Parent centrioles are characterized in most organisms by individual morphological traits and have distinct asymmetries that provide different functional properties. By contrast, mother and daughter centrioles are morphologically undistinguishable during Drosophila male gametogenesis. Here we report the presence of previously unrecognized microtubule-based structures that extend into the peripheral cytoplasm of the Drosophila polar spermatocytes at the onset of the first meiosis and are positive for the typical centriolar protein Sas-4 and for the kinesin-like protein Klp10A. These structures have a short lifespan and are no longer found in early apolar spermatocytes. Remarkably, each polar spermatocyte holds only one microtubule-based structure that is associated with one of the sister centriole pairs and specifically with the mother centriole. These findings reveal an inherent asymmetry between the parent centrioles at the onset of male meiosis and also uncover unexpected functional properties between the mother centrioles of the same cells.