Abstract
The gene-targeting experiment is a powerful tool for clarifying the functions of each gene product. For instance, establishment of a gene-knockout mouse, undoubtedly, contributes to our understanding of the functions of each gene in vivo. However, assuming that the gene product is expressed in various lineage cells, the phenotype in this knockout mouse exhibits a mixture of defects in various lineage cells. Thus, to compensate for this weak point, cell-based gene-knock experiments are required. Since the DT40 chicken B cell line shows a high frequency of homologous recombination, this cell line can be used for rapid dissection of each gene product at the cellular level.
