Regulation of early embryo development by extra

Principal Supervisor name and department:
Dr. Jose Gutierrez-Marcos, SLS
Second Supervisor name and department:
Dr. Ann Dixon, Chemistry
Where will the student be based?
Split between two departments (60% SLS and 40%
PhD project title: Regulation of early embryo development by extra-embryonic secreted peptides
Project description:
Although much is known about the role of non-peptide hormones in regulating growth and
development in animals and plants, relatively little is known about the significant role played by
small signalling peptides in regulating such processes. Recently, an increasingly large number of
genes encoding small, secreted peptides in animals and plants have been implicated in mediating
cell–cell interactions. For example, there are demonstrated roles for peptide signals in defence
responses, cell proliferation and differentiation, maintenance of stem cell identity, and in
reproduction. Although both genetic and biochemical methods have thus far been used to identify
and characterise such peptides, we remain ignorant of their biophysical properties and how their
physical structure relates to function and performance. This project aims to establish a link between
the physical and chemical properties of a group of newly identified peptide ligands that regulate
early embryogenesis in plants. Surprisingly, these peptides are secreted from extra-embryonic tissues
and interact with a discrete class of transmembrane receptors to regulate the asymmetric division of
the zygote. Therefore the principal aim of this project is to decipher how these peptides mediate
such specific developmental response in early embryos.
Key experimental skills involved:
The student will carry out a series of experiments designed to determine the peptide structure and
the interactions with transmembrane receptors. Analytical ultracentrifugation (AUC) will be used to
determine protein size, shape and oligomeric state, as well as key thermodynamic properties
including the free energy of dissociation for any SCR oligomers and complexes formed. Protein
nuclear magnetic resonance (NMR) methodologies will also be used to confirm the first highresolution solution state structures of these proteins. NMR methods could also provide information
of the dynamics of these proteins and their interactions with other key ligands and proteins.
Complementing these techniques, mutagenesis in combination with in vivo and invitro genetic
complementation assays will provide information on the biological significance of the peptides.
Because these peptides share striking homology to other secreted peptides found in distantly related
plant species, it is envisaged that this project will become a template for future analyses in crop plant
Costa LM, Yuan J, Rouster J, Paul W, Dickinson H, Gutierrez-Marcos JF. (2012) Maternal control of
nutrient allocation in plant seeds by genomic imprinting. Current Biology 24;22(2):160-5.
Ohki S, Makoto T, and M Mori (2011) The NMR structure of stomagen reveals the basis of stomatal
density regulation by plant peptide hormones. Nature Communincation 2; 512-515
Contact details for application enquiries:
Jose Gutierrez-Marcos, Email:
Keywords: cell-cell communication, signalling, peptide, NMR, structure
Please state below which hazards may be connected with this studentship:
The studentship will entail work involving:
Chemicals – high toxicity and category 1 or 2 substances
Organo-phosphate or carbamate pesticides
√ if applies
Skin or respiratory sensitising agents (e.g. insect parts, organic
dusts from animals, spores, pollen, antibiotics, fibres, chemical
sensitisers, wood dust etc)
Significant manual handling
Mechanical repetition where the frequency and duration are
Working in areas where there are temperature extremes
Driving vehicles (tractors, fork lifts, ATVs etc)
Crop planting, harvesting, recording or grading
Working in close proximity to bees or other stinging insects
Working at height [>2 m] (using various types of access
Working with noisy or vibrating equipment
Working at night (between 11.00pm and 6.00am)
Food handling
Other significant hazards (specify)