Team:UT Dallas/project part3

From 2013.igem.org

Quorum sensing molecules are naturally used by S. Mutans to regulate population growth and competency. At normal levels, Competency Stimulating Peptide (CSP) allows a local population of S. Mutans to share plasmids and grow. When the concentration of CSP gets too high CSP activates a genetic pathway that causes some cells to activate cell-death. This allows the colony to remain at sustainable levels. We can take advantage of this natural population control to cause the equilibrium concentration of S. mutans in the oral cavity to decrease drastically. E. coli can produce CSP constitutively at a high rate. When placed in the mouth, these engineered E. coli will raise the concentration of CSP and cause the death of any nearby S. mutans cells. The natural quorum signaling system involves five gene products encoded by: ComA, ComB, ComC, ComD, ComE. The comC gene encodes a competence-stimulating peptide (CSP) precursor. ComC and ComDE lie adjacent on the chromosome and, together with their gene products, constitute a peptide (CSP)-signaling system including a generating pathway (comC) and a responding pathway (comDE). The other two genes, cslA and cslB, are located in a separate region of the chromosome and encode a CSP-specific secretion apparatus consisting of an ATP-binding cassette (ABC) transporter (ComA) and its accessory protein (ComB), which are involved in the processing and export of the CSP.

What We Did: We attempted to use these quorum sensing molecules which are naturally used by S. Mutans. When placed in the mouth, our engineered E. Coli cells sense the presence of S.mutans and raise the concentration of CSP and cause the death of any nearby harmful cells.