A biolistic process for in vitro gene transfer into chicken embryos

Chicken embryos kept in culture medium were bombarded using a high helium g as pressure biolistic device. To optimize the factors that affect transform ation efficiency, the lacZ gene under control of the human cytomegalovirus immediate early enhancer/promoter was used as a reporter gene. There was an inverse relationship between survival rate and transformation efficiency. The best conditions obtained for high embryo survival and high transformati on efficiency were achieved with 800 psi helium gas pressure, 500 mmHg vacu um, gold particles, an 8 cm DNA-coated microparticle flying distance to the embryo and embryo placement 0.5 cm from the center of the particle dispers ion cone. Under these conditions, transformation efficiency was 100%, survi val rate 25% and the number of expression units in the embryo body cells ra nged from 100 to 1,000. Expression of green fluorescent protein was also de tected in embryos bombarded under optimal conditions. Based on the results obtained, the biolistic process can be considered an efficient method for t he transformation of chicken embryos and therefore can be used as a model s ystem to study transient gene expression and tissue-specific promoters.