Davidson - Research

Research

There are 6 different ammeline riboswitches that have been created by Neil Dixon, John N. Duncan, Torsten Geerlings, Mark S. Dunstan, John E. G. McCarthy, David Leys, and Jason Micklefield. Their research is described in the article Reengineering orthogonally selective riboswitches. The article shows that the two best riboswitches seem to be M6 and M6C, however neither of these riboswitches appear to be truly "off". When there is no ammeline present there is still a production of GFP. This presents a problem because when using a fitness module like antibiotic resistance those cells that are not producing ammeline will still be able to live, not allowing for the evolution that we desire. Another problem comes from the fact that the induction factor (the expression when ammeline is present/the expression when ammeline is absent) is not extremely high.

Figures From Report

Secondary structure model of the parental add A-riboswitch in the ON-state

Data From Testing Different Riboswitches

There are two options that we can do to fix these riboswitch systems

1) Create a better riboswitch that is "off" when ammeline is absent, but still allows for an "on" system when ammeline is present

2) Change the fitness module from antibiotic resistance to a thyA module