Localized all-cell knock-out (LACKO) strategy is needed for studying adult stage diseases.

Knock-out (KO) mouse models have been increasingly used to dissect the roles of genes in development, diseases, and injuries. The conventional KO approach allows study of the role of the targeted genes in all cells, but it sometimes results in embryonic lethality. Using the classical conditional KO approach, reseachers can avoid embryonic lethality, but they cannot modulate genes in a temporally controllable way. The inducible KO technique, which has been used to study the role of a gene in life processes at the adult stage, avoids the potential interfering role of changed structures and functions of the tissues/organs resulting from the early KO of the gene in the non-inducible conditional knock-out approach. However, it is difficult to develop clinically applicable therapies for some diseases or injuries based on the results obtained from inducible KO studies since the total summed role of the genes of interest in those diseases or injuries cannot be determined and, therefore, the potential therapeutic effects of the applied modulators of the activity of the targeted genes cannot be predicted. To solve this problem of the classical conditional and inducible KO approaches, researchers need to simultaneously knock out a gene in all cells locally-a process called the localized all-cell KO (LACKO) strategy. We describe the concept of this new strategy in detail in this article.