Improved Yeast Expression System by Could-Clone

It is well known that there are three types of commonly used systems in the field of gene engineering, including prokaryotic expression system (Escherichia coli expression system, also called E. coli expression system), yeast expression system (Pichia P. expression system) and mammalian cell expression system. The prokaryotic expression system is widely used because of the advantages of simple operation, low cost and high expression.

But at the same time, prokaryotic expression system also has some shortcomings, such as it is prone to form of inclusion body, has no posttranslational processing and so on

In order to avoid the shortage of prokaryotic expression system itself, Cloud-Clone Corp. has developed and established a yeast expression platform. exogenous proteins expressed by yeast have a certain ability to posttranslational processing, and the foreign proteins can be emfolded and glycosylation processed to some extent, those proteins are more stable than the one expressed by prokaryotic cells. It is particularly suitable for expressing eukaryotic genes and functional proteins. Some yeast expression systems have the secreted signal sequence, which can secrete the foreign protein to the medium, so it is easy to be purified.

The general steps of the yeast expression of foreign genes are shown in Figure 1, but during the development process, Cloud-Clone Corp. found that the original yeast expression system also has some deficiency, such as methanol is easy to be volatiled in the process of the cultivation, then its concentration will be reduced, thereby affecting the final efficiency, etc.

Cloud-Clone Corp. has improved the above system as follows:

1. During the process of the expression of target proteins, in order to achieve the optimal amplification conditions of the strains, the concentration of methanol was kept by constant addition of the extra methanol. So that the maximum of the target protein yield was ensured;

2. In the culture of yeast containing positive clones during proliferation, the sealing device of culture flask was improved to increase the yeast proliferation efficiency;

3. After the expression, the target protein in the culture supernatant was detected by SDS-PAGE electrophoresis, the expression conditions and purification methods were optimized again according to the characteristics of target protein.

After optimizing this expression platform by Cloud-Clone Corp., and the expression efficiency and purity of the target protein were elevated, as shown in Figure 2, after the modified amplification and purification scheme, the yeast expressed CCL18 is better (Lane 2), relative to the protein expressed by conventional yeast expression system (Lane 1). This improvement will bring great conviniences to researchers.

Fig 2. Expression of CCL18 by improved or conventional yeast expression systems

For more information, please see http://www.cloud-clone.com/.