The ability to control the self-renewal of stem cells represents a “holy grail” for biomedicine. However, the mechanisms underlying this crucial stem cell property are poorly understood. In skeletal muscle, stem cells self-renew via the formation of a limited number of so-called reserve cells from myoblasts, the muscle progenitor cells. Unlike myoblasts, reserve cells do not terminally differentiate but return to quiescence. The mechanisms of this fate decision are largely unknown. A technical challenge is to control the function of endogenous candidate regulators with high temporal and spatial precision.
The Kassel lab at KIT has identified a putative role for a transcriptional co-regulator in the fate decision between differentiation and the return to quiescence. However, this factor is also involved in earlier stages of differentiation. Thus, novel tools are needed to manipulate its function in a spatially and temporally highly controlled manner.
The Di Ventura lab at Uni Heidelberg develops innovative optogenetic tools to precisely and reversibly control the subcellular localization and activity of proteins. Recently, they engineered a tool to control with light the nuclear localization of a protein of interest by photocaging a nuclear localization peptide signal within the LOV2 domain.
The global aim of this collaborative project is to develop optogenetic tools for controlling myoblast fate decision. Our approach to control endogenous candidate proteins with a very high temporal and spatial precision is to engineer the LOV2 domain to photocage short effector peptides which affect the function of target proteins. As a test case, we will use a peptide which inhibits our candidate transcriptional co-regulator, in order to dissect its function during myoblast fate decision.
Importantly, these novel tools and principles will enrich the synthetic biology toolbox for manipulating cellular processes with high spatiotemporal precision in other areas of stem cell research and biology in general.