Partial human genome RNAi screen to identify genes involved in brain size regulation and cancer development.

Summary

The most common cause of autosomal recessive primary microcephaly (MCPH), a neurodevelopmental disorder characterized by reduced brain size and mental retardation, is mutation in the Abnormal Spindle Microcephaly Assembly (ASPM) gene (formerly named Abnormal Spindle Microtubule Associated gene)(1). ASPM is localized at the spindle poles during mitosis. ASPM knockdown using small interfering RNAs (siRNAs) results in reorientation of the mitotic spindle/cleavage furrow and cytokinesis failure (2). ASPM is an extremely important protein as changes in cell division orientation during neurodevelopment has serious consequences on the size of the developing brain and spindle misorientation results in cancer development through induction of genomic instability, tissue disorganisation, metastasis and expansion of cancer stem cells.

Reverse genetic screens using libraries of small interfering RNAs are a powerful tool in identifying multiple genes involved in developmental and disease pathways (3). To identify genes involved in brain size regulation and cancer formation two siRNA screens (human protein kinase and human ubiquitin libraries) have been performed using loss of ASPM at the spindle pole as the screen readout. The student will (i) analyse the screen results to identify genes involved in ASPM regulation and localisation, mitotic progression and division orientation and cellular cytotoxicity (ii) perform siRNA knockdown experiments to validate candidate gene hits (iii) perform molecular and cell biology studies to further characterise the nature of the hits, how they modify or interact with ASPM and what is the specific function of the interaction in relation to cell division, to identify candidate MCPH genes and identify novel cancer therapeutic targets.

Timeliness and training opportunities:

Cell division is one of the most fundamental cellular processes and this project aims to further our understanding of the regulation of mitosis with specific reference to neurogenesis and cancer formation. The project will provide interdisciplinary training in functional genomics approaches (comprising high-throughput screening and image analysis) followed by molecular and cell biology studies (immunofluorescence microscopy, Western blotting, Co-Immunoprecipitation studies, cloning, and specific functional assays based on the nature of the candidate hits). There will be an early emphasis on image analysis and the interpretation of large datasets, which will provide important transferable bio-analytical and bioinformatics skills.

References:

• Bond et al., (2002), Nat Genet. 32:316-20. PMID: 12355089
• Higgins et al., (2010) BMC Cell Biol 11:85. PMID: 21044324
• Wheyway et al., (2015) Nat Cell Biol. 17:1074-1087 PMID:26167768

A degree in biological sciences, dentistry, medicine, midwifery, nursing, psychology or a good honours degree in a subject relevant to the research topic. A Masters degree in a relevant subject may also be required in some areas of the Faculty. For entry requirements for all other research degrees we offer, please contact us.

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