Two papers reporting on mouse models for studying cellular reprogramming are published this week in Nature Methods.
Induced pluripotent stem cells are derived from mature cells by introduction of a set of transcription factors that cause the cells to regress to an embryonic stem cell-like state. This reprogramming process is still poorly understood and there is a need for tools to enable its study.
Konrad Hochedlinger, Rudolf Jaenisch, and their respective colleagues now independently report reprogrammable mouse strains that will be useful for this purpose. Both teams introduced the genes that encode the four reprogramming factors as a single set into a defined location in the mouse genome. This solves problems of variability in factor expression, which affects reprogramming, as well as difficulties in maintaining the mouse strains. The factors could be activated using added chemicals. This methodology should make it possible to reprogram any type of mouse cell in a controlled fashion.
These reprogrammable mouse models will enable the controlled study of reprogramming in different cell types and genetic backgrounds. They will also allow for the comparison of genetically identical embryonic stem cells and induced pluripotent stem cells, a crucial question in the field.