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Team:UCSF/Project/Conjugation/Design
From 2013.igem.org
What is conjugation? In nature, bacterial strains rarely exist as distinct populations. Instead, they are almost always found in mixed populations where they compete for resources. Conjugation is a naturally occurring process in bacteria that allows genetic material to be transferred between a population of bacterial cells. This process promotes gene diversity, and in certain situations, provides a competitive advantage for the recipient cell.
By combining CRISPRi and conjugation, we’ve come up with a system that will allow us to specifically target certain populations within a microbiome. To do this, an engineered cell capable of conjugating must be introduced into a microbiome of interest. The engineered cell, or donor cell is capable of conjugating (proteins necessary for conjugation are contained in the genome) and carries a conjugative plasmid, which codes for a catalytically dead Cas9 (dCas9) protein and guide RNA (gRNA) for a specific gene that is present in the targeted population.
Upon conjugation with the target population, the conjugative plasmid would be transferred. Both dCas9 and gRNA would subsequently be expressed in the recipient cell, and the complex formed will repress the targeted gene specified by the gRNA, shutting down certain cell functions.
