Characterization of endogenous promoters of GapC1 and GS for recombinant protein expression in Phaeodactylum tricornutum

The endogenous promoter of glutamine synthetase (GS) strongly drove green fluorescent protein (GFP) expression during all growth phases of the diatomPhaeodactylum tricornutum and under multiple growth conditions, including nitrogen starvation and increased light intensity. These results indicate that the GS promoter could be utilized as a strong promoter for the genetic engineering of P. tricornutum. AbstractAlthough diatoms have been utilized as a cellular factory to produce biopharmaceuticals, recombinant proteins, and biofuels, only a few numbers of gene promoters are available. Therefore, the development of novel endogenous promoters is essential for the production of a range of bioactive substances. Here, we characterized the activities of endogenous promotersglyceraldehyde-3-phosphate dehydrogenase (GapC1) andglutamine synthetase (GS) ofPhaeodactylum tricornutum using green fluorescent protein (GFP) under different culture conditions. Compared with the widely used fucoxanthin chlorophyll-binding protein A (fcpA) promoter, theGS promoter constitutively drove the expression of GFP throughout all growth phases ofP.  tricornutum, regardless of culture conditions. Additionally, the GFP level driven by theGapC1 promoter was the highest at the log phase, similar to thefcpA promoter, and increased light and nitrogen-starvation conditions reduced GFP levels by inhibiting promoter activity. These results suggested that theGS promoter could be utilized as a strong endogenous prom...

Source: MicrobiologyOpen - October 28, 2021 Category: Microbiology Authors: Erdenedolgor Erdene ‐Ochir, Bok‐Kyu Shin, Md Nazmul Huda, Eun Ha Lee, Dae‐Geun Song, Choonkyun Jung, Cheol‐Ho Pan Tags: ORIGINAL ARTICLE Source Type: research