Next generation transgenic technologies for the chick

The chick embryo is a well-established model for the study of vertebrate development, particularly because it is possible to access the embryos in ovo and carry out experimental manipulations that include grafting of embryonic material, application of growth factors, transient transfection with gene constructs by electroporation or infection with retroviral vectors. The chicken is also a model species for investigation of the general physiology of birds, for example photoperiodism and seasonality. The domestic fowl is of course an important agricultural species and there is significant research in the UK into aspects of the genetics and physiology of the chicken relevant to poultry breeding and production. A significant tool that was missing from the repertoire of technologies available to researchers studying the chicken was the ability to make genetic modifications. We established an effective method for production of transgenic birds, by injection of lentiviral vectors into chick embryos in new laid eggs, followed by culture of injected embryos to hatch. We are proposing additional development of transgenic tools for genetic modification of the chick. Our aim is to improve the efficiency of production of transgenic birds and demonstrate that we can use novel tools to investigate gene function directly in birds. These advances will support research in basic biology of vertebrate development through to understanding aspects of disease susceptibility and resistance in poultry.

The main output from this project was the development of a very efficient method for introduction of novel genes into the chicken via culture of primordial germ cells from chick embryos, the precursors of the sperm and eggs in adult birds. We also showed that we could apply technologies developed elsewhere for regulation of transgene expression and gene knockdown by expression of short interfering RNAs.