Molecular Genetics Studentship Further Particulars 2010

Background

The genetic disorder Werner’s Syndrome (WS) is a progeroid condition in which patients show symptoms of accelerated ageing. While individual progeroid syndromes do not accurately recapitulate all aspects of normal ageing, they can inform on the underlying fundamental biological events. WS is known to be caused by mutation of the WRN locus, which encodes a RecQ-type helicase, with an additional unique 3’-5’ exonuclease activity. Unlike vertebrates, Drosophila does not possess a single WRN polypeptide with both helicase and exonuclease activities – instead these discrete activities are encoded by separate loci. We have identified a homologue of the human WRN exonuclease, DmWRNexo (1)⁠ and demonstrated that DmWRNexo protein has 3'-5' exonuclease activity (2)⁠. DmWRNexo mutants show a very high frequency of chromosome rearrangement and are highly sensitive to the Topoisomerase I inhibitor camptothecin, both characteristics of human WS cell lines (1)⁠. A second 3'-5' exonuclease related to WRN appears to be the Drosophila orthologue of EXDL2 (3)⁠, an exonuclease of uncertain function but implicated in DNA repair, particularly repair of interstrand crosslinks. Drosophila mutant for DmEXD2 have phenotypes similar to those of DmWRNexo mutants. Preliminary data suggests a role for human EXDL2 in mitochondrial genome stability.

Aims and objectives

Aim: This project seeks to investigate the role of DmWRNexo and DmEXD2 in DNA repair and nuclear and mitochondrial genome stability.

Objectives: (each of which leads to subsidiary objectives):

Investigate the nature of DmWRNexo maternal effect lethality, using a variety of transgenic techniques coupled with cell biological and biochemical approaches. Identify candidate partner RecQ helicases for DmWRNexo and DmEXD2
Generate novel alleles of DmEXD2, and use these together with existing alleles to evaluate impact on genome stability, maternal effect lethality and mitochondrial genome stability, particularly with regard to the repair of interstrand crosslinks. Identify/characterise candidate partner RecQ helicases for DmWRNexo and DmEXD2
Identify/characterise candidate partner RecQ helicases for DmWRNexo and DmEXD2. Characterise further the roles of DmWRNexo and DmEXD2.

Methods

The student will use sophisticated Drosophila genetic techniques, together with cell biological and molecular approaches. Full training will be given.

Time table

Year 1: Initiate transposable element excision/deletion mutagenesis screens for DmEXD2 and DmWRNexo, characterise resulting mutants.

Year 2: Use new alleles together with existing alleles and transgenic strains to: further define function and interactions with other proteins; further investigate maternal effect lethality; initiate molecular and genetic analysis of nuclear and mitochondrial genome stability

Year 3: Detailed molecular and genetic analysis of nuclear and mitochondrial genome stability in a variety of mutant and transgenic configurations.

Facilities: All equipment and infrastructure necessary for successful completion of the proposed project available

Training: The Open University provides a structured Research and Training regime to ensure students receive appropriate research-specific transferable skill training, including risk assessment, research ethics, teamwork, leadership, public understanding of science, presentation and writing skills. During the studentship, the student will assemble a portfolio documenting progress. Project-specific training includes a thorough grounding in Drosophila molecular genetic techniques and molecular biology and biochemistry techniques. Full pastoral and intellectual support will be provided by independent academic advisors.

References

Molecular Genetics Studentship Further Particulars 2010

1. Saunders, R. D., Boubriak, I., Clancy, D. J., Cox, L. S. , Aging Cell. 7, 418-425 (2008) http://view.ncbi.nlm.nih.gov/pubmed/18346216.

2. Boubriak, I. et al., Biogerontology. 10, 267-277 (2009) http://view.ncbi.nlm.nih.gov/pubmed/18956248.

3. Cox, L. S., Clancy, D. J., Boubriak, I., Saunders, R. D. , Annals of the New York Academy of Sciences. 1119, 274-288 (2007).

Molecular Genetics Studentship Further Particulars 2010

For detailed information and how to apply call Michelle Duke on 01908 659672 or email . Closing date for applications 27 September 2010