Control of daughter centriole formation by the pericentriolar material

Abstract

Controlling the number of its centrioles is vital for the cell as supernumerary centrioles result in multipolar mitosis and genomic instability 1,2 . Normally, just one daughter centriole forms on each mature (mother) centriole 3,4 ; however, a mother centriole can produce multiple daughters within a single cell cycle 5,6 . The mechanisms that prevent centriole 'overduplication' are poorly understood. Here we use laser microsurgery to test the hypothesis that attachment of the daughter centriole to the wall of the mother inhibits formation of additional daughters 7,8 . We show that physical removal of the daughter induces reduplication of the mother in S-arrested cells. Under conditions when multiple daughters simultaneously form on a single mother, all of these daughters must be removed to induce reduplication. Intriguingly, the number of daughter centrioles that form during reduplication does not always match the number of ablated daughter centrioles. We also find that exaggeration of the pericentriolar material (PCM) via overexpression of the PCM protein pericentrin 9 in S-arrested CHO cells induces formation of numerous daughter centrioles. We propose that that the size of the PCM cloud associated with the mother centriole restricts the number of daughters that can form simultaneously.A typical centrosome in an animal cell consists of two microtubule-based cylindrical structures, termed the centrioles, surrounded by a cloud of pericentriolar material (PCM). Most of the components responsible for the major centrosomal functions, for example, the Υ-tubulin ring complex, reside in the PCM. However, in the absence of centrioles, the PCM cloud becomes structurally unstable, and eventually disperses 10 . Thus, the number of centrioles ultimately defines the number of centrosomes in the cell.Normally, in somatic cells new ('daughter') centrioles form in association with mature ('mother') centrioles. This process, known as "centriole duplication", is initiated when cells enter S phase, and the daughter centriole remains associated with its mother, in a strictly orthogonal configuration (i.e., 'diplosome'), until the second half of the ensuing mitosis 11-13 . Recent work suggested that as long as the daughter remains attached to the mother formation of additional daughters is not possible 7,8 . *Correspondence should be addressed to AK (Wadsworth Center, PO Box 509, Albany, NY 12201−0509, phone: (518)486−5339; fax: (518)486−4901; E-mail: khodj@wadsworth.org). Author contributions Experiments were conducted by J.L.; P.H. was responsible for EM preparation and data collection; V.M. designed, assembled, and maintained the laser microsurgery workstation; A.K. directed the work. Experiments were planned by J.L. and A.K. Competing financial interestsThe authors declare that they have no competing financial interests. Fig. S3). NIH Public AccessUpon ablation of the daughter centriole within a diplosome, the remaining mother consistently (20 of 20 experiments) developed a new daughter (Figs. 1A, S4). The interval be...

One to only two: a short history of the centrosome and its duplication

“…New centriole assembly appears to be controlled at the level of the centrioles and surrounding PCM. Consistent with this notion, increasing the size of the PCM by pericentrin overexpression allows assembly of multiple procentrioles near the mother centriole [81].…”

DrosophilaBld10 Is a Centriolar Protein That Regulates Centriole, Basal Body, and Motile Cilium Assembly

“…Therefore, another function of the centriolar adjunct could be to promote the formation of a second centriole in the vicinity of the centriole/basal body. In support of this idea, recent studies have shown that PCM promotes new centriole assembly, perhaps by concentrating ␥-tubulin (Dammermann et al, 2008;Loncarek et al, 2008).…”

Promoter hijack reveals pericentrin functions in mitosis and the DNA damage response

“…12,13 Pericentrin overexpression caused expansion of the PCM, allowing the formation of multiple daughter centrioles independently of any spatial or numerical control from the mother centrioles. 14 This observation prompted the hypothesis that the mother centriole's principal role in centriole assembly is the regulation and specification of a PCM scaffold, rather than the provision of a template. 14 Loss-of-function analyses of pericentrin have demonstrated roles for the protein in controlling centrosome functions during both mitosis and interphase.…”

“…14 This observation prompted the hypothesis that the mother centriole's principal role in centriole assembly is the regulation and specification of a PCM scaffold, rather than the provision of a template. 14 Loss-of-function analyses of pericentrin have demonstrated roles for the protein in controlling centrosome functions during both mitosis and interphase. Injection of anti-pericentrin antibodies disrupted mitotic spindle formation in frog embryos.…”