PhD Studentship in Medical Biosciences (PhD Studentship)
Reference Number: R2302
Project title: bHLH transcription factors in Drosophila intestinal homeostasis
Adult intestinal stem cells (ISCs) are the population with the greatest tumour initiation potential in the gut [1,2]. Understanding how stem cells are regulated in healthy tissue can help develop new strategies for cancer treatment. ISCs maintain homeostasis by neutral competition, whereby ISCs choose stochastically whether to divide either asymmetrically into an ISC and a differentiating cell, or symmetrically into either two ISCs or two differentiating cells [3,4]. This is important for cancer initiation, as cancerous mutations could be ‘flushed out’ of the stem compartment , but also pre-cancerous mutations could expand through the stem cell pool .
Neutral competition also occurs in the Drosophila intestine , where we propose to address the molecular regulation underlying neutral competition. A candidate mechanism is Notch/Delta-dependent lateral inhibition, whereby stem cells would mutually inhibit their self renewal. The phenotypes of Notch signalling mutants are compatible with this view [7-11]. However, lateral inhibition requires an underlying network of of bHLH transcription factors. While there is evidence supporting the existence of such a network , whereby heterodimers of class A/E bHLH factors would promote the stem cell fate and be opposed by factors of the HES family (E(spl) in Drosophila) downstream of Notch, its presence and relationship with lateral inhibition has not been established in the Drosophila intestine.
We aim at identifying a class A bHLH factor involved in ISC maintenance, both by focusing on candidates known to be expressed in the intestine and by screening other known bHLH factors in Drosophila. This work will provide both mechanistic insight into ISC neutral competition and an in vivo setting where to study the roles of bHLH proteins with roles in tumourigenesis and metastasis of gastrointestinal cancers, but whose functions have not been explored in vivo.
Start date: October 2014
Number of Studentships: 1
Footnotes: Please see the Further Information tab for footnotes/references.
This studentship consists of full UK/EU tuition fees, as well as a Doctoral Stipend matching UK Research Council National Minimum (£13,863 p.a. for 2014/15, updated each year).
One studentship is available.
Residency: The studentship is open to applicants worldwide. Non-EU applicants will need to fund the difference between the UK/EU tuition fee rate and the overseas tuition fee rate.
Academic criteria: A degree with at least 2:1 result or equivalent is required. A degree in Biology would be advantageous but any science graduate is encouraged to apply. Good understanding of Genetics would be highly desirable.
How to Apply
Consideration is automatic on applying for Doctor of Philosophy (Biosciences), with a start date of October 2014 via Cardiff University's Online Application Service. In the research proposal section of your application, please specify the project title and supervisors of this project and copy the project description in the text box provided. In the funding section, please select "I will be applying for a scholarship / grant" and specify that you are applying for advertised funding from the School of Biosciences
The deadline for applications is 11 July 2014.
Cardiff University reserves the right to close applications early should sufficient applications be received.
Informal enquiries should be directed to Swapna Khandavalli by emailing KhandavalliS@cardiff.ac.uk or telephoning +44 (0)2920 875 243.
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- Zhu, L. et al. 2009 nature07589. Nature 457, 603–608. (doi:10.1038/nature07589)
- Lopez-Garcia, C., Klein, A. M., Simons, B. D. & Winton, D. J. 2010 Intestinal stem cell replacement follows a pattern of neutral drift. Science 330, 822–825. (doi:10.1126/science.1196236)
- Snippert, H. J. et al. 2010 Intestinal crypt homeostasis results from neutral competition between symmetrically dividing Lgr5 stem cells. Cell 143, 134–144. (doi:10.1016/j.cell.2010.09.016)
- Vermeulen, L., Morrissey, E., van der Heijden, M., Nicholson, A. M., Sottoriva, A., Buczacki, S., Kemp, R., Tavaré, S. & Winton, D. J. 2013 Defining stem cell dynamics in models of intestinal tumor initiation. Science 342, 995–998. (doi:10.1126/science.1243148)
- Snippert, H. J., Schepers, A. G., van Es, J. H., Simons, B. D. & Clevers, H. 2013 Biased competition between Lgr5 intestinal stem cells driven by oncogenic mutation induces clonal expansion. EMBO reports, n/a–n/a. (doi:10.1002/embr.201337799)
- de Navascués, J., Perdigoto, C. N., Bian, Y., Schneider, M. H., Bardin, A. J., Martinez-Arias, A. & Simons, B. D. 2012 Drosophila midgut homeostasis involves neutral competition between symmetrically dividing intestinal stem cells. EMBO J 31, 2473–2485. (doi:10.1038/emboj.2012.106)
- Micchelli, C. A. & Perrimon, N. 2006 Evidence that stem cells reside in the adult Drosophila midgut epithelium. Nature 439, 475–479. (doi:10.1038/nature04371)
- Ohlstein, B. & Spradling, A. 2006 The adult Drosophila posterior midgut is maintained by pluripotent stem cells. Nature 439, 470–474. (doi:10.1038/nature04333)
- Ohlstein, B. & Spradling, A. 2007 Multipotent Drosophila intestinal stem cells specify daughter cell fates by differential notch signaling. Science 315, 988–992. (doi:10.1126/science.1136606)
- Bardin, A. J., Perdigoto, C. N., Southall, T. D., Brand, A. H. & Schweisguth, F. 2010 Transcriptional control of stem cell maintenance in the Drosophila intestine. Development 137, 705–714. (doi:10.1242/dev.039404) .