Quantitative analysis of incorporation dynamics of conserved Centriole proteins in Drosophila early embryos

Thesis

To divide efficiently, cells of animals and many other higher eukaryotes, rely upon centrosomes to help nucleate the bipolar mitotic spindle. At each division, two centrosomes are required, such that one centrosome is ultimately inherited by each daughter cell. Consequently, centrosomes must duplicate precisely once during each cycle of cell division. At the core of each centrosome is a mother centriole that can duplicate by growing a new daughter centriole off its side, which will later mature into a mother and nucleate its own centrosome. The core components of the centriole are highly conserved across higher eukaryotes, despite this there is still a lack of detail regarding their function and their hierarchy of assembly.

In this thesis, I perform a comparative analysis of the incorporation dynamics of several conserved centriole proteins, using both standard and super-resolution microscopy, and the Drosophila early embryo as a model. I show that the daughter centrioles in the Drosophila early embryo appear to begin assembling earlier than previously reported. Further, I provide evidence that several core centriole proteins may be recruited into a transient centrosomal primordial “soup” in addition to the centriole proper. In addition, I refine the order of assembly of the centriole - allowing incorporation of Sas-6, Ana2, Ana3, CEP135, Ana1 and Asl to be placed on a continuous timeline alongside the cell cycle. Finally, through the use of CEP135 mutants, I show that, CEP135 does not appear to be necessary to recruit Ana1 into centrioles, in contrast to previous findings.

In summary, my work redefines the initial incorporation dynamics of centriole assembly, challenging several previous assumptions and providing new avenues for interrogation of the specific functions of the core centriole proteins.

Authors: Harrison, T

• DOI: 10.5287/ora-m8bobve5y
• Type of award: MSc by Research
• Level of award: Masters
• Awarding institution: University of Oxford
• Language: English
• Keywords: Dynamics; Centrosome; Centriole; Drosophila; Centriolar; Centrioles; Incoroporation; Assembly
• Subjects: Molecular Biology; Biology