Team:Penn State/MSC Results


Multiple Start Codons Overview

Multiple Start Codons

A frustrating yet commonly observed phenomenon in the lab is the production of unexpected proteins. These occurrences may be explainable by multiple start codons in the mRNA strand. Codon slippage is a theory practically untouched by research, and this project aspires to shed some light on the issue.

Multiple Start Codons

Sample navigation menu:

Overview | Design | Results


The initial circuit for this project has recently been completed. The relative fluorescence of both RFP and sfGFP reporters was tested in a TECANM1000.

The graph above shows the relative fluorescence of two reporters corresponding to two start codons in the circuit. The reporters indicate the ribosome's preference for one start codon over the other in protein translation. Super-folder GFP (sfGFP) is preferred in this construct, as shown by the high amount of relative fluorescence. Though the amount of green fluorescence significantly outweighs the red fluorescence, there is still a measurable amount of RFP expression in the cell. The presence of both reporters indicates that multiple start codons may be possible in DH10B E.coli, since the ribosome recognizes both start codons and initiates the translation of both proteins.

Further Application

This construct tests only a 7-nucleotide separation between start codons. Since these preliminary results show that the recognition of multiple start codons is possible within the cell, further research will continue to investigate the effect of ribosome binding site translation initiation rate, as well as length between codons, on codon slippage. To view the full list of intended sequences which will be tested in this genetic circuit, please visit our parts page.