Future Works

Our final goal is to develop the universal diagnosis kit. But if we express more than one modified antigen receptor, signal from these receptors will be cross-talked. To prevent this crosstalk, we decided to selectively express specific modified receptor. Our first plan was to embed all gene of modified antigen receptors with promoter whose activators are different. But these idea have some problems. First of all, though we don't activate genes, there are expressions of genes. It is not possible to suppress gene 100%. So we planned to use the 'conjugation' of Schizosaccharomyces pombe. So we will make 'antigen-binding' yeasts of different antigens and 'signal-transduction' yeast separately. And the diagnostician conjugate 'antigen-binding' yeast of certain antigen and common 'signal transduction' yeast before the diagnosis.

Our Final Goal and Problem of Cross-talking implementation

Our final goal is to develop the universal diagnosis kit for every disease whose antibody is produced. To perform this goal, the yeast should express modified antigen receptor of wanted disease, STAT1 proteins and have GFP gene whose promoter have GAS element. Most easiest way to way to detect existence of antigen is to express every antigen receptor on one yeast cell and integrate these signal into GFP with common STAT1 dimerization pathway. But this way have problems. Though the GFP is expressed, we can't sure which antigen is detected, because any antigen binding can turn on the GFP expression. Therefore, the cross-talking implementation can't be used for differential diagnosis because it can't eliminate any disease which can turn on the GFP expression.

Disadvantage of All-in-One Implementation

So we tried to selectively express modified antigen receptor genes to use promoter with different activator molecule. With this All-in-One implementation, one yeast cell have genes for GFP with GAS element, STAT1 signal transduction molecule and every modified antigen receptor with promoters whose activator is different. In theoretically, this implementation solve the problem of cross-talking of modified antigen receptors. But this implementation have two problems.

1. Though we don't activate the promoter, yeast cell express the gene naturally. Therefore, we can't solve the problem of cross-talk perfectly.
2. We need to assign promoters with different activator for each modified antigen receptors. But the number of disease is more than the number of promoters with different activator obviously.

Our Final Implementation : Conjugation

So we gave up to insert genes for every modified antigen receptors. But we still wanted to make universal diagnosis kit. So we looked for the way to 'combine the genes'. And we found the 'conjugation of S.pombe' With certain condition, If spores from different yeast can be mated, their genes can be in same cell. Therefore, we divide our diagnosis system to specific gene and common genes. And each set of genes are inserted into different yeast. And the diagnostician would make the conjugated cell with whole sensing pathway to stimulate the mating of yeast spore.

Life Cycle of S.pombe

Before description of our idea, we should talk about the life cycle of S.pombe. Generally, S.pombe is haploid organism. So they have only one copy of each gene. But in starving condition, Cells of S.pombe become diploid through mating. And this mating allow yeast have the gene from different parents. Therefore, with the starvation, we can induce the conjugation of S.pombe and integrate genes from two different gene sets.

How to implement?

With the conjugation which is stimulated by starvation, we can make diploid cell whose genes are from different parents. We planned to divided genes for our project into two genesets. The gene for STAT1 and GFP with GAS element are common to every diagnosis kit, while gene for individual modified antigen receptor are depend on the target antigen. Therefore, the common genes are in the same yeast cell and genes for individual antigen receptors are in each cells.

How to Use?

With the sets of antigen-detecting cells and common signal transduction cells, we can make the whole system to detect antigen. For example, if the diagnostician want to detect TB antigen, he should induce the conjugation of yeast cell with TB antigen receptor gene and yeast cell with common signal transduction cells to make whole TB detecting diploid yeast. And for another antigen, diagnostician only need to change the antigen receptor cell for cell with the gene of receptor which detect target antigen.