The use of microinjection to study gene function in the zebrafish has become widespread in recent years. This includes ectopic expression of genes by introducing DNA (1 ) or RNA into embryos or injection of blocking molecules, such as RNA encoding truncated proteins (2 ) or antibodies, to perturb the function of endogenouse gene products (3 ,4 ). The method involves microinjection of DNA and RNA molecules into the cytoplasm of one-cell-stage embryos using pressure microinjector and micromanipulator as described below.
