Identification of factors controlling eye regeneration in a multi-ocular planarian flatworm

Humans are generally considered to have poor regenerative capacities. In contrast, many other organisms are capable of complex structural regeneration. Planarian flatworms have emerged as excellent models for regeneration research, and provide important insight into cancer, stem cell regulation and ageing. Asexual Schmidtea mediterranea reproduce naturally via fission, and can regenerate entire animals from small body parts, including new heads complete with brains and a medial pair of eyes (ocelli). There is now considerable knowledge about the genes regulating eye regeneration in this species due in large part to its amenability to gene knockdown via RNAi, and the availability of considerable genomic resources. However, little is known about how eye number and position are regulated by signals emanating from the Central Nervous System (CNS) or other patterning molecules (Wnt etc).

Regeneration research in the Somorjai group is aimed at using invertebrate models to elucidate mechanisms promoting repair after injury. We have begun to study the process of eye development and regeneration in planarians from the Polycelis complex. Our laboratory colony is sexually reproducing; in addition to producing on average 4 progeny per cocoon, individuals have regeneration capabilities comparable to those of Schmidtea mediterranea. We can therefore easily study both juvenile development and adult regeneration processes. Polycelis also differ from other standard laboratory species in having a large number of laterally placed eyes, evenly spaced along the body margin and at a considerable distance from the brain and CNS. When juveniles hatch, they have several pairs of eyes only, which rapidly increase in number as the flatworms grow. The timing and patterning of eye regeneration in mature adults however appear to be somewhat different, suggesting a complex relationship between the developing and mature CNS and eye formation.

We have already successfully developed in situ hybridisation and immunohistochemistry techniques in the laboratory, and genomic resources are publically available. In this PhD project, you will use bioinformatics, molecular biology including gene cloning and whole mount in situ hybridisation, immunohistochemistry, confocal microscopy and RNAi to develop Polycelis as a model for eye regeneration. Specific objectives include:
1. characterisation of known eye gene markers in Polycelis during development and/regeneration. These could include ovo, sine oculis etc.
2. characterisation of eye development and regeneration in relation to CNS development.
3. development of RNAi gene knockdown in Polycelis to assess candidate functions causing phenotypes in eye number, spacing, medio-lateral position etc.
4. comparative studies of interesting novel candidates in Schmidtea mediterranea to assess the generality of your conclusions.

This project is a collaborative project with the laboratory of Dr Francesc Cebria, University of Barcelona. The ideal candidate will have experience with some of all of the techniques required for the project; however, training will be provided. Possession of a Masters degree in a relevant biological field is desirable.

Please send informal enquiries to Dr. Ildiko Somorjai: [Email Address Removed]

Lab webpage: http://www.st-andrews.ac.uk/profile/imls