Our journey and achievements for the iGEM 2025 competition.
All competition deliverables, including the Wiki, Presentation Video, and Judging Form have been completed.
The Attribution page has been completed, detailing the distribution of labor and the contributions of each team member. We are divided into four subgroups: Dry Lab, Wet Lab, Integrated Human Practices, and Art Design. Each subgroup assumed distinct tasks in the project. We express our gratitude for the help provided by our supervisors, professors, internal and external advisers for their advice and technical support.
Learn MoreThe Description page has been completed, detailing our project concept. The purpose of our project design is to enhance the precision of yeast cells' response to complex adverse conditions on the basis of strengthening their stress resistance. We started with an overview of yeast stress resistance. We subsequently examined the current therapies available for yeast to survive. We have found that the current yeast stress resistance has problems such as a single response to stress and a large metabolic burden of stress resistance. For this purpose, we first sorted out the components currently used in yeast for stress resistance and constructed a database. Among these components, we selected the three promoters with the best response effects and three stress-resistant genes, which respectively respond to high-temperature, hypertonic, and ROS stress conditions. Based on these components, we respectively constructed: 1. Cell factories with composite stress resistance functions, introducing three stress resistance combination components into the cell factories that produce carotene to increase their yield in complex adverse conditions. 2. The ternary oscillator system ensures that yeast maintains resistance to complex adverse conditions while reducing the metabolic burden.
Learn MoreOur contributions to future iGEM teams and the wider community allow us to share the knowledge and skills we've gained. We created and documented new parts in the Parts Registry and actively engaged in various human practices. For example, we conducted synthetic biology workshops, exhibitions and Instagram stories and videos. Additionally, we developed an educational card game that highlights the function of synthetic biology components used in yeast modification. A significant contribution to the iGEM community was co-hosting the CCiC & Synbiopunk 2025, which united teams from the China region to share insights, inspire one another, and foster collaboration. These efforts align with iGEM's core values, emphasizing global involvement in synthetic biology and building strong networks.
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We have completed the Engineering page for our Wiki, detailing our project's journey through the entire engineering cycle. Our main objective is to identify suitable stress-resistant promoters and genes and verify their functions in yeast. We iterated the cycle several times: first, we modified our original design by Combine different stress-resistant components (DESIGN). Next, we assembled the necessary genetic material (BUILD) and tested it following our protocol (TEST). We figured out which genes were the best options.
Learn MoreWe have completed a Human Practices page showcasing our progress and achievements in engaging with the wider community. We are committed to staying informed about advancements in scientific research on yeast modification and the related social issues. To achieve this, we conducted in-depth interviews with professors specializing in relevant fields to evaluate research value and gather expert advice. Additionally, we aim to Publicize to the public the basic principles of synthetic biology and yeast's stress resistance by providing accessible activities. This includes Giving lectures in primary and secondary schools in the Beijing area, conducting synthetic biology workshops for Undergraduates, and posting Instagram stories and reels. We have Carried out communicate activities with local universities such as the Wuhan University and Beijing Institute of Technology, as well as other universities in the Asia-Pacific region like Beijing University of Chinese Medicine. We also visited many enterprises for academic conversations, such as Synsea Biopha and Wuxi Biologics.
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With the aim to close the gap in knowledge, debunking popular misconceptions, and equipping individuals with relevant and current information, our team has proactively launched several engaging activities and designed High-quality lectures that aimed to educate public about synthetic biology. We have designed a multiplayer card game set against the backdrop of synthetic biology, which enables players to utilize synthetic biology components commonly used in scientific research to engage in an exciting offensive and defensive competition with other players. Through this game, the public can not only experience the joy of competing with other players, but also understand the functions and uses of various components in scientific research. All the initiatives we implemented have been systematically and thoroughly documented, with the aim of providing a reference and replicable model for others. For secondary school students, we organized science popularization lectures; for university faculty and students, we held thematic forums; and for the general public, we actively participated in various science exhibitions. Through the careful implementation of these plans, we effectively enhanced outcomes and expanded our reach. Our goal is not only to ensure the scalability of the project measures but also to continuously promote public attention and discussion on synthetic biology and yeast engineering.
Learn MoreWe have successfully constructed two innovative composite parts. The first part features time-sensitive stress resistance, enabling yeast to transiently express stress-resistant proteins when under adverse conditions and promptly shut down the expression pathway afterwards, thereby reducing metabolic burden. The second part allows yeast to sense complex stress conditions and dynamically self-regulate the expression level of stress-resistant genes. Together, these composite parts enhance yeast stress resistance through dual optimization of timeliness and regulatory complexity. The time-sensitive part consists of a stress-responsive promoter, a resistance gene, and a degradation tag. In the first design phase, we preliminarily selected stress-inducible promoters and corresponding genes from a built database targeting various stress conditions. These components were assembled into plasmids and introduced into yeast cells to evaluate their resistance effects in vivo. Based on experimental data, we identified three top-performing element sets responsive to high temperature, hyperosmotic stress, and ROS, respectively. During the second phase, we adopted a similar strategy to screen degradation tags—short amino acid sequences obtained from literature—by fusing them to a fluorescent protein and expressing them in yeast. The tag with the strongest degradation performance was selected, and its half-life was quantitatively determined. In the final phase, the stress-responsive elements and the optimal degradation tag were integrated into a single system and transformed into yeast to validate the time-controlled stress resistance capability. The oscillator part is constructed based on a classical triple-repressor oscillator circuit, in which repressor proteins and their corresponding promoters are coupled with response genes for three distinct stress conditions. Each repressor is itself under the regulation of one of these stresses. When a specific stress occurs, it relieves the repression on the corresponding gene circuit. For example, under high temperature, the inhibition of λcl by LacI is lifted, allowing expression of both λcl and the associated heat-responsive genes to proceed without suppression. This leads to a high production of proteins that confer thermotolerance. Furthermore, thanks to the mutual repression within the triple-repressor oscillator network, the expression of these heat-resistance proteins rapidly declines once the stress is removed. This design enables rapid and dynamic response to complex stress conditions. The two parts collectively represent a significant advance in synthetic biology for enhancing cellular stress resistance. The time-sensitive module enables precise, transient expression of stress-response genes, effectively reducing metabolic burden by ensuring timely degradation of proteins after stress alleviation. The oscillator-based module introduces dynamic and self-regulating behavior, allowing cells to not only respond rapidly to multiple complex stresses but also automatically downregulate the response once the stressor is removed. Together, they provide a robust, tunable, and resource-efficient framework for engineering intelligent stress adaptation systems in yeast, offering novel strategies for bioproduction and cellular engineering under real-world variable conditions.
Learn MoreIn the process of the project, we met two critical problems – how to validate our oscillator and how to apply our oscillator to practical production. The first problem raised from the difficulties we encountered in the process of constructing and validating the feasibility of the oscillator via complete wet experimental method. We estimate that fully using wet experimental methods to complete the entire process from oscillator construction to verification will take 3 to 4 months, which is hardly possible for out iGEM project. Therefore, we came up with the idea of using computational simulations to quickly verify the feasibility of oscillators, that is, a stochastic model. Based on the structure of the gene oscillator, we divide the chemical reactions in the system into six categories. By calculating the occurrence trend of each reaction at a certain moment and randomly selecting a reaction at that moment, we successfully simulated the situation in actual cells and verified the feasibility of the gene oscillator. Further, to simulate the circumstances under which stress occurs, based on our gene oscillator model, we creatively decided to increase the transcription rate when a specific gene is suppressed in order to simulate the scenario where the inhibition of a specific gene is alleviated under stress. And the other problem is that all data we collected only consists of the fluorescence intensity of the oscillators at each moment, which is difficult to use for human judgment of the system's condition, such as the type and intensity of stress encountered. In order to cope with this predicament, we designed another deterministic model based on several differential equations to infer the state of the system via fitting the relevant parameters in the equations. Compared to the stochastic model, this model is much more efficient in operation, making it possible for real-time monitoring. Besides, we creatively designed proper method to infer the state of the system with the parameters we got. So in a word, we established a stochastic model and a deterministic model and developed appropriate methodologies based on the structure of our gene oscillator to separately address the two problems – how to validate our oscillator and how to apply our oscillator to practical production.
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