A novel functional gene selection method provides a systematic view of cell migration

Cell migration is a central process that is essential for embryonic development, wound repair, inflammatory response, homeostasis and tumor metastasis. A method of genome-wide selection based on the gain-of-function has been devised to identify novel cell migrationpromoting genes in cultured cells. After the introduction of the retroviral mouse brain cDNA library into NIH3T3 mouse fibroblast cells, migration-promoted cells were selected by a three-dimensional migration assay using cell culture inserts. After five rounds of enrichment, cDNAs were retrieved from the cells that passed the selection processes. Cell migration-promoting activity was con-firmed by independent migration assays for the retrieved cDNAs. Multiple cell migration-promoting genes were successfully isolated by this method. The genes identified can be used to gain a systematic view of cell migration. The gain-of-function selection method described here can be combined with RNAi-mediated loss-of-function screen or selection to be a more powerful tool for the systems biology research of cell migration.