Abstract
SummaryBackgroundCentrosomes have important roles in many aspects of cell organization, and aberrations in their number and function are associated with various diseases, including cancer. Centrosomes consist of a pair of centrioles surrounded by a pericentriolar matrix (PCM), and their replication is tightly regulated. Here, we investigate the effects of overexpressing the three proteins known to be required for centriole replication in Drosophila—DSas-6, DSas-4, and Sak.ResultsBy directly observing centriole replication in living Drosophila embryos, we show that the overexpression of GFP-DSas-6 can drive extra rounds of centriole replication within a single cell cycle. Extra centriole-like structures also accumulate in brain cells that overexpress either GFP-DSas-6 or GFP-Sak, but not DSas-4-GFP. No extra centrioles accumulate in spermatocytes that overexpress any of these three proteins. Most remarkably, the overexpression of any one of these three proteins results in the rapid de novo formation of many hundreds of centriole-like structures in unfertilized eggs, which normally do not contain centrioles.ConclusionsOur data suggest that the levels of centriolar DSas-6 determine the number of daughter centrioles formed during centriole replication. Overexpression of either DSas-6 or Sak can induce the formation of extra centrioles in some tissues but not others, suggesting that centriole replication is regulated differently in different tissues. The finding that the overexpression of DSas-4, DSas-6, or Sak can rapidly induce the de novo formation of centriole-like structures in Drosophila eggs suggests that this process results from the stabilization of centriole-precursors that are normally present in the egg.
Highlights
The centrosome is the main microtubule-organizing center in animal cells, and it consists of a pair of centrioles surrounded by an amorphous pericentriolar matrix (PCM) [1]
GFP-DSas-6 associated with centrioles at all stages of the cell cycle in embryos, larval brain cells, and spermatocytes (Figures 1A–1C), and DSas-6 antibodies weakly stained centrioles at all stages of the cell cycle in embryos
We cannot rule out the possibility that some GFP-DSas-6 or endogenous DSas-6 is associated with the PCM
Summary
The centrosome is the main microtubule-organizing center in animal cells, and it consists of a pair of centrioles surrounded by an amorphous pericentriolar matrix (PCM) [1]. Genome-wide RNAi and genetic screens in C. elegans have identified five proteins required for centriole duplication—SPD-2, ZYG-1, SAS-5, SAS-6, and SAS-4 [9,10,11,12,13,14,15,16]. These proteins localize to centrioles and act in sequence to orchestrate centriole duplication in the worm embryo. The loss of SAS-5 or SAS-6 blocks formation of the central tube of the daughter centriole, an early event in the initiation of centriole duplication. SAS-4 is the last protein recruited and it is required for the addition of singlet microtubules to the perimeter of the central tube [18]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
