<p>To eliminate the signal interference from the natural mating process of <i>Saccharomyces cerevisiae</i>, we knocked out the original mating receptor STE2 in the yeast. Through experimentation, we confirmed that the knockout reduced the background noise signals in the wild-type yeast, thereby enhancing the stability of the system. In the experiment, we adopted a strategy of separately testing the upstream and downstream components of the system before integrating and validating them. First, we used the GFP reporter gene instead of lactate dehydrogenase to test whether the muscone molecular switch introduced into <i>Saccharomyces cerevisiae</i> could function properly. Meanwhile, we used the galactose promoter to express lactate dehydrogenase, verifying whether lactate dehydrogenase could alter the anaerobic metabolic pathway of <i>Saccharomyces cerevisiae</i> and successfully secrete D-lactate. After that, we synthesized the complete biological system and validated that under the muscone signal, the yeast could synthesize and secrete D-lactate.</p>
<p>For more details, see the <ahref="https://2024.igem.wiki/Tsinghua/therapy-system"style="color: #FF5151">Therapy system</a>.</p>
<h3>Colonization system</h3>
<p>To enable our engineered Saccharomyces cerevisiae to specifically function at the small intestinal lesions of IBD patients, we have designed the colonization system. This system consists of two main components: the tetrathionate sensor TtrSR and the adhesion protein Als3. TtrSR can detect the chemical signals of extracellular IBD marker tetrathionate and promote the expression of downstream genes in the signaling pathway. Als3 is a cell surface protein from Candida albicans that acts as an adhesin, mediating adhesion to epithelial cells, endothelial cells, and extracellular matrix proteins. We have chosen Saccharomyces cerevisiae as the chassis organism for our project. By constructing the TtrSR system in Saccharomyces cerevisiae and expressing Als3 protein downstream, we aim to achieve specific colonization at the small intestinal lesions of IBD patients, which enables our therapy systems to work better and more efficiently.</p>
<p>To enable our engineered Saccharomyces cerevisiae to specifically function at the small intestinal lesions of IBD patients, we have designed the colonization system. This system consists of two main components: the tetrathionate sensor TtrSR and the adhesion protein Als3. TtrSR can detect the chemical signals of extracellular IBD marker tetrathionate and promote the expression of downstream genes in the signaling pathway. Als3 is a cell surface protein from Candida albicans that acts as an adhesin, mediating adhesion to epithelial cells, endothelial cells, and extracellular matrix proteins. We have chosen Saccharomyces cerevisiae as the chassis organism for our project. By constructing the TtrSR system in Saccharomyces cerevisiae and expressing Als3 protein downstream, we aim to achieve specific colonization at the small intestinal lesions of IBD patients, which enables our therapy systems to work better and more efficiently.</p>
<p>For more details, see the <ahref="https://2024.igem.wiki/Tsinghua/colonization"style="color: #FF5151">Colonization system</a>.</p>
