Phosphorylation-Based miRNA Sensor Circuit Design
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Solution Overview
Problem
Balancing the activation and repression strength in genetic circuits to accurately respond to microRNA inputs remains challenging.
Innovation Solution
The integration of kinase and phosphatase pairs that phosphorylate or dephosphorylate a transcription factor, whose expression is tuned by microRNAs, allows for conformational changes that control DNA-binding ability and output molecule expression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional genetic circuits use simple activators and repressors, then the circuit design is simple, but the activation and repression strength cannot be accurately balanced and tuned
Solution Approach 1:
The patent applies parameter changes by utilizing phosphorylation state as a tunable parameter to control transcription factor activity. By adjusting the phosphorylation level of the transcription factor through kinase and phosphatase regulation, the system achieves precise control over activation and repression strengths, resolving the contradiction between simple circuit design and precise parameter tuning.
Solution Approach 2:
The patent introduces dynamics by making the transcription factor's activity state-dependent through phosphorylation. The transcription factor transitions between active and inactive states based on phosphorylation status, enabling dynamic tuning of activation and repression strengths while maintaining relatively simple circuit architecture.
2Adaptability or versatility
If the genetic circuit uses phosphorylation-based transcription factor control, then the activation and repression strength become tunable, but the device complexity increases due to integration of kinases and phosphatases
Solution Approach 1:
The patent applies universality by designing a modular system where kinase-phosphatase pairs can be universally applied to control different transcription factors. The same basic phosphorylation mechanism serves multiple functions: tuning activation strength, controlling repression strength, and enabling dynamic response to microRNA inputs, thereby achieving high adaptability with controlled complexity.
Solution Approach 2:
The patent uses phosphorylation as an intermediary mechanism between the microRNA input and the transcription factor output. This intermediary layer allows for tunable activation and repression strengths by translating microRNA-mediated mRNA degradation into controllable transcriptional activity, managing the complexity through a clear functional hierarchy.
3Reliability
If the transcription factor undergoes conformational change upon phosphorylation, then the DNA-binding ability is controlled, but the measurement and detection of phosphorylation state becomes more difficult
Solution Approach 1:
The patent replaces direct mechanical detection of phosphorylation state with a functional readout system. Instead of directly measuring phosphorylation, the system uses the conformational change-induced DNA binding activity as the measurable output, substituting a difficult-to-measure biochemical state with a functional genomic response that is easier to detect and quantify.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enables easy tunability of activation/repression strengths, enhancing the performance of cell state classifiers in detecting microRNA profiles.
Implementation Method 1
a constitutive promoter operably linked to a nucleotide sequence encoding a kinase that phosphorylates the activator and produces a phosphorylated activator
Implementation Method 2
a constitutive promoter operably linked to a nucleotide sequence encoding a phosphatase that de-phosphorylates the phosphorylated activator
Implementation Method 3
the transcription factor undergoes a conformational change upon phosphorylation or dephosphorylation, allowing or abrogating its DNA-binding ability
Data Source
AI summary
Provided herein are genetic circuits and cell state classifiers for detecting the microRNA profile of a cell. The cell state classifiers of the present disclosure utilize phosphorylation state of a transcription factor to control classifier output. Kinases and phosphatase pairs that function in phosphorylating or dephosphorylating the transcription factor are integrated into the circuit, their expression tuned by the presence of microRNAs of interest (e.g., in a cell). The genetic circuits and cell state classifiers may be used in various applications (e.g., therapeutic or diagnostic applications).