Gene Targeting

Publisher Summary

This chapter summarizes the historic background and the current state of gene targeting technology with specific regard to neuroscience research. Random mutagenesis is a very powerful method for elucidating gene function in simpler model organisms. Given the size of the genome and slow reproductive cycles, however, a more direct approach is required for mammalian models. The capacity of most mammalian somatic cells to carry out homologous recombination between endogenous loci and exogenous DNA. Pluripotent embryonic stem cell lines have been established that maintain the ability to intermingle with the early mouse embryo and contribute to the germline, thereby conferring heritability, even after extensive culturing in vitro. The process of homologous recombination had been known to exist in yeast and during the prophase I of meiotic cell division during gametogenesis. In somatic cells, however, this faculty was generally believed to be absent, until the appearance of curious results of gene conversion in human fetal globin genes and head-to-tail concatemerizations of microinjected plasmid DNA copies in the process of genomic integration strongly suggested that this mechanism operates in any cell. Subsequently, unequivocal evidence was furnished opening the door for specific gene modifications in somatic mammalian cells.