Overview B-cell receptors (BCRs) are unique in their ability to each recognize one of a range of antigens and produce an intracellular response. The antigen that we would like to detect is beta-amyloid, since beta-amyloid plaques are implicated in Alzheimer’s disease. BCRs consist of multiple components, including the membrane-bound proteins IgM, CD79A, and CD79B. The membrane-bound IgM is the part of the BCR that recognizes a specific antigen. For this project, we plan to modify a commercially available antibody against beta-amyloid plaques into an IgM so that we can integrate into our BCR. Normally, when an antigen binds to the IgM part of the BCR, CD79A and CD79B become phosphorylated with the help of Lyn, thus recruiting Syk. Though in B cells antigen binding leads to a signaling cascade that induces cell proliferation, we would like the binding of beta-amyloid to transmit a signal (in the form of a transcription factor) to our diagnosis/treatment module. Our solution involves TEV protease, which cleaves a particular amino acid sequence (TEV cleavage site) that can be used as a linker in fusion proteins. In our system, transcription factors are linked to CD79A and CD79B by TEV cleavage sites and Syk is fused to a TEV protease. Thus, when Syk is recruited to the BCR upon beta-amyloid binding, the attached TEV protease will come in close proximity to its cleavage site, where it can cut and release the attached transcription factor into the cell. This transcription factor can then go on to activate the genes involved in our diagnosis/treatment module. Additionally, our modified BCR could be adapted to detect any antigen and release any transcription factor, making it a particularly useful synthetic biology tool. |
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Proteins needed |
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