Figure Burney et. al 2009 One of the graphs observed in order to choose miRNA candidates to characterize. The three miRNAs, miR-34c-5p, miR-9, miR-34-b are shown to be downregulated and have a significant fold difference (p*=0.05 p**<0.05) compared to their respective levels in healthy eutopic endometrial cells. These measurements were from an endometrial biopsy and taken using quantitative polymerase chain reaction (qPCR), similar to the other sources we also studied.
Our circuit utilizes the natural function of miRNA to regulate gene expression. Depending on the miRNA activity in a cell, different levels of our desired gene will be expressed. This allows our circuit to produce a differential output depending on whether the cell has dysregulated miRNA. This is achieved by attaching 4 tandem sites complementary to the affected miRNA following a gene of interest. This is called the miRNA target site (miRNA-ts).
These 4 tandem sites for miRNA binding were tested by coding for them distal to the gene for red fluorescent protein. We were able to see a ten fold repression upon increasing the concentration of siRNA from 0 to 1 nM. Saturation appeared at about 10 nM.
Unlike more common cell lines like MCF7 and HEK293, tHESC is not a highly characterized cell line. This meant that the levels of our eight miRNA candidates were completely unknown in tHESC. We set out to characterize our miRNA target sites (miRNA-ts) in tHESC using a miRNA sensor.
