Inducible Asymmetric Cell Division and Cell Differentiation in a Bacteria

Multicellular organisms achieve greater complexity through cell divisions that generate different cell types. We engineered a simple genetic circuit that induces asymmetric cell division and subsequent cell differentiation in Escherichia coli. The circuit involves a scaffolding protein, PopZ, that is stably maintained at a single cell pole over multiple asymmetric cell divisions. PopZ was functionalized to degrade the signaling molecule, c-di-GMP. By regulating synthesis of functionalized PopZ via small molecules or light, we can chemically or optogenetically control the relative abundance of two distinct cell types, characterized by either low or high c-di-GMP levels. Differences in c-di-GMP levels can be transformed into genetically programmable differences in protein complex assembly or gene expression, which in turn produce differential behavior or biosynthetic activities. Programmable bacterial cell differentiation is a new genetic tool of synthetic biology and biotechnology. We called this strategy as Microbial Stem Cell Technology (MiST), which enables a growing microbial culture to stably maintain two or more distinct cell types in a ratio that can be genetically programmed and/or dynamically controlled during cultivation. It is contemplated that employing of MiST would increase product yield in microbial fermentations and advanced engineering of biomaterials.