title: The centriolar protein Bld10/Cep135 is required to establish centrosome asymmetry in Drosophila neuroblasts.
abstract: Centrosome asymmetry has been implicated in stem cell fate maintenance in both flies and vertebrates [1, 2]. Drosophila neuroblasts, the neural precursors of the fly's central nervous system [3], contain molecularly and physically asymmetric centrosomes, established through differences in pericentriolar matrix (PCM) retention [4-7]. For instance, the daughter centriole maintains PCM and thus microtubule-organizing center (MTOC) activity through Polo-mediated phosphorylation of Centrobin (Cnb) [7, 8]. The mother centriole, however, quickly downregulates PCM and moves away from the apical cortex, randomly migrating through the cytoplasm until maturation sets in at prophase [4-6, 8]. How PCM downregulation is molecularly controlled is currently unknown, but it involves Pericentrin (PCNT)-like protein (PLP) to prevent premature Polo localization and thus MTOC activity [9]. Here, we report that the centriolar protein Bld10, the fly ortholog of Cep135, is required to establish centrosome asymmetry in Drosophila neuroblasts through shedding of Polo from the mother centrosome. bld10 mutants fail to downregulate Polo and PCM, generating two active, improperly positioned MTOCs. Failure to shed Polo and PCM causes spindle alignment and centrosome segregation defects, resulting in neuroblasts incorrectly retaining the older mother centrosome. Since Cep135 is implicated in primary microcephaly, we speculate that perturbed centrosome asymmetry could contribute to this rare neurodevelopmental disease.
authors: Biozentrum, University of Basel, Klingelbergstrasse 50-70, 4056 Basel, Switzerland.
authors: Priyanka
authors: P
authors: Singh
authors: Biozentrum, University of Basel, Klingelbergstrasse 50-70, 4056 Basel, Switzerland.
authors: Anjana
authors: A
authors: Ramdas Nair
authors: Biozentrum, University of Basel, Klingelbergstrasse 50-70, 4056 Basel, Switzerland. Electronic address: clemens.cabernard@unibas.ch.
authors: Clemens
authors: C
authors: Cabernard
mesh_terms: D000818:Animals; D018385:Centrosome / Q000502:physiology*; D017931:DNA Primers / Q000235:genetics; D004330:Drosophila / Q000235:genetics / Q000502:physiology*; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D007091:Image Processing, Computer-Assisted; D018613:Microscopy, Confocal; D058953:Neural Stem Cells / Q000502:physiology*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D034622:RNA Interference; D017422:Sequence Analysis, DNA
chemical_list: C542499:CEP135 protein, Drosophila; D017931:DNA Primers; D029721:Drosophila Proteins; C072004:polo protein, Drosophila; D017346:Protein Serine-Threonine Kinases