The development of a multicellular organism can be thought of as a series of hierarchical
patterning events, dividing groups of cells into nested domains that give rise to
tissues, organs, and specialized cell types.
By building gene regulatory circuits that are capable of patterning populations of
microbes, we can investigate the minimal
genetic architecture required for this most basic developmental process and build synthetic
developmental systems that can be used as a platform for future engineering.
By using a previously developed two-channel synthetic
quorum-sensing-based signaling system we were able to build a genetic regulatory
circuit in which cells sending and receiving either signal repress the
ability to send and receive the other signal,
resulting in bistability on the population level -
that is, cells come to a collective decision about which signaling state they are in.
This leads to the formation of spatial domains of gene expression both at the
level of colonies, and in larger populations.