The proteins that trigger the growth of embryos are the subject of a new study using zebra fish at NUI Galway. A group of biochemists hopes to improve understanding of genetic processes in the fish; work that may ultimately be applied in the human context, whether it is the growth of the smallest fertilised egg or the highly complex adult.
Zebra fish - not to be confused with the fouling zebra mussel which recently arrived in Irish waters - are like humans in that they have vertebrae.
Embryonic development is usually a difficult process to study in mammals because it proceeds in utero. Most of the current knowledge, for example, has arisen from studies of the fruit fly, an invertebrate (an animal without a backbone).
The Department of Biotechnology at NUI Galway has chosen zebra fish for this research because egg fertilisation and development are external and can easily be monitored in the laboratory without halting the growth process.
The species is a native of the Ganges river in India but should be readily adaptable to Ireland, once water is maintained at 28.5 C. Stocks are being brought to Ireland by a Galway commercial fish supplier.
They will work with an initial stock of between 50 and 60 fish, which at the seven-month stage will be used for breeding.
"We already know the complete genetic information for the development of an embryo is present in the fertilised egg," according to Ms Deirdre O'Connor, a postgraduate student working on the study. It is being supported by Forbairt's Basic Research Programme with £42,000 over three years.
"The process by which our genes are selectively activated is a fundamental mechanism for the development of the embryo. In this research we are examining the regulation of the genes' activity, which is controlled by a family of proteins called homeobox proteins," she explained.
Different versions of these proteins, and in different concentrations, switch on growth in different parts of the embryo. For example, a certain combination will prompt head growth.
"It is fascinating to see what turns genes on and off, and it has huge consequences for our development."
She has a particular interest in one gene which produces a protein known as CEBP, which is important for the development of liver cells.
It has already been established in mice that if the gene producing this protein is not active, they do not have a properly-developed liver and have very low deposits of fat.
Once the team gets the fish to spawn, eggs will be taken at various stages of development. Ribonucleic acid (RNA) will then be extracted which allows for "gene expression" to be evaluated.
Deirdre O'Connor knows this ambitious project could help fill in the bigger picture, and significantly improve our understanding of our genetic make-up and growth patterns.
