PGAP
Introduction
Glyceraldehyde-3-phosphate-dehydrogenase (GAP) promoter is one of the strongest constitutive promoter in Pichia pastoris[1].
Characterization
In order to test the function of PGAP, we construct "PGAP-EGFP-terminator" (Figure 1). If PGAP is functional, we can test the fluorescence intensity of EGFP in supernatant samples obtained from the culture of recombinant P.pastoris GS115 strain.
Figure 1 Gene circuit of PGAP-EGFP-terminator
Our results matched the general expected trend (Figure 2). After fermentation experiment in BMMY medium containing 1% methanol. The fluorescence intensity of the samples of recombinant P.pastoris GS115 containing the EGFP gene was essentially unchanged over time. At the same time, we measured the growth curve of the strains.
Figure 2 Fluorescence intensity and OD600 absorbance of samples obtained at different time points from the culture of corresponding recombinant P.pastoris GS115 containing EGFP gene.
Reference
[1] Waterham, H.R., Digan, M.E., Koutz, P.J., Lair, S.V., Cregg, J.M., 1997. Isolation of the Pichia pastoris glyceraldehyde-3-phosphate dehydrogenase gene and regulation and use of its promoter. Gene 186 (1), 37-44.