We are driving episomal expression of a protein in S.cerevisiae through pUG vector. Compared to the level of expression 2 years ago, we see a reduction, in the same batch. I was wondering if it is common for S.cerevisiae to lose episome upon scale up or in later generations?
We do not have a selectable marker in the scaled up culture. At lower culture size, the selection is auxotrophic.
Hi there,
If I understand well, you applied selection only on the small scale culture? As there was no selection for plasmid containing cells in the scaled up culture, cell tends naturally to lose the plasmid encoding for the protein so the yield is lower... Repeat the culture with selection pressure.
Hi there,
If I understand well, you applied selection only on the small scale culture? As there was no selection for plasmid containing cells in the scaled up culture, cell tends naturally to lose the plasmid encoding for the protein so the yield is lower... Repeat the culture with selection pressure.
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