?-TuRC Heterogeneity Revealed by Analysis of Mozart1.

ABSTRACT: Microtubules are essential for various cell processes [1] and are nucleated by multi-protein ?-tubulin ring complexes (?-TuRCs) at various microtubule organizing centers (MTOCs), including centrosomes [2-6]. Recruitment of ?-TuRCs to different MTOCs at different times influences microtubule array formation, but how this is regulated remains an open question. It also remains unclear whether all ?-TuRCs within the same organism have the same composition and how any potential heterogeneity might influence ?-TuRC recruitment. MOZART1 (Mzt1) was recently identified as a ?-TuRC component [7, 8] and is conserved in nearly all eukaryotes [6, 9]. Mzt1 has so far been studied in cultured human cells, yeast, and plants; its absence leads to failures in ?-TuRC recruitment and cell division, resulting in cell death [7, 9-15]. Mzt1 is small (?8.5 kDa), binds directly to core ?-TuRC components [9, 10, 14, 15], and appears to mediate the interaction between ?-TuRCs and proteins that tether ?-TuRCs to MTOCs [9, 15]. Here, we use Drosophila to investigate the function of Mzt1 in a multicellular animal for the first time. Surprisingly, we find that Drosophila Mzt1 is expressed only in the testes and is present in ?-TuRCs recruited to basal bodies, but not to mitochondria, in developing sperm cells. mzt1 mutants are viable but have defects in basal body positioning and ?-TuRC recruitment to centriole adjuncts; sperm formation is affected and mutants display a rapid age-dependent decline in sperm motility and male fertility. Our results reveal that tissue-specific and MTOC-specific ?-TuRC heterogeneity exist in Drosophila and highlight the complexity of ?-TuRC recruitment in a multicellular animal.

SUBMITTER: Tovey CA 

PROVIDER: S-EPMC6065531 | biostudies-literature | 2018 Jul

REPOSITORIES: biostudies-literature