Blizard Institute - Barts and The London

Defining the processes of nuclear degradation in keratinocytes

Controlled nuclear degradation is required throughout development, homeostasis and injury. Critical though this process is, little is known about the associated mechanisms. An enduring problem is the inability to easily locate degrading nuclei, save for in pathologies that are known to disrupt the nuclear lamina, such as myopathies, progerias and in cancer. This is unlikely to reflect normal nuclear degradation. Keratinocyte terminal differentiation requires complete nuclear degradation and provides a unique opportunity to visualise and define this process from beginning to end.

AKT1-mediated phosphorylation of Lamin A/C is required for nuclear degradation in differentiating keratinocytes (Naeem et al., 2015 Cell Death and Differentiation), and we and others have shown that a modified form of autophagy removes nuclear material containing both lamins and chromatin from differentiated keratinocyte nuclei (Akinduro et al., 2016 J Invest Dermatol). Understanding the mechanisms and timescale of nuclear degradation and finding markers to define these stages has value beyond the keratinocyte, extending to other tissues where nuclear clearance is required, such as the lens and reticulocytes, as well as in diseases of nuclear integrity where these processes are impaired or accelerated.

In this project the student will visualise the nuclear degradation process in keratinocytes and identify key stages in the nuclear degradation process. The student will express Green Fluoresent Protein-labelled nuclear lamins and Red Fluorescent Protein-labelled nuclear proteins. Together this will visualise the nuclear lamina and the nuclear contents. The student will look at this in fixed cultures to identify stages in nuclear degradation and will then visualise nuclear degradation in real-time using live imaging confocal microscopy. If time allows the student will then relate these nuclear degradation stages to changes in gene and protein expression. In this project the student will learn a wide range of cell biology skills, including cell culture, transfection, microscopy as well as western blotting and qPCR approaches.

Applications are invited from candidates with at least an upper-second class honours degree or equivalent in an area relevant to the project. Proficient English language skills are essential. Please contact Dr Ryan O'Shaughnessy (r.f.l.oshaughnessy@qmul.ac.uk) to apply.