Affinity Purification Sequencing for Transcription Factor Mapping
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Solution Overview
Problem
Current methods for mapping transcription factor (TF) interactions with their target genes are limited by the significant effort required for cloning and expressing tagged TFs, particularly in non-model organisms and for high-throughput studies, which restricts the ability to comprehensively survey TF binding sites across diverse species.
Innovation Solution
The method involves affinity-labeling transcription factors during in vitro transcription and translation using tRNA loaded with biotinylated lysine, allowing for biotin-DAP-seq, which enables the direct expression of TFs from genomic DNA without plasmid construction, facilitating rapid and cost-effective generation of genome-wide binding site maps across multiple species.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional cloning and expression methods are used to produce tagged TFs, then reliable TF-DNA binding data can be obtained, but the process requires significant time and effort
Solution Approach 1:
The method performs preliminary action by incorporating biotin labels directly during in vitro transcription and translation of TFs from genomic DNA, eliminating the need for prior plasmid construction and cloning steps. This preliminary labeling enables direct affinity purification and sequencing, resolving the time-consuming nature of traditional methods while maintaining data reliability.
Solution Approach 2:
The invention extracts the essential function of TF expression and labeling from the complex plasmid-based cloning workflow. By using in vitro transcription and translation systems with biotinylated amino acids, the method separates the TF production step from the affinity purification step, allowing direct binding assays without traditional molecular cloning intermediaries.
2Ease of manufacture
If traditional plasmid construction and cloning methods are used, then tagged TFs can be produced, but the process is costly and time-consuming
Solution Approach 1:
The method creates copies of TF proteins directly from genomic DNA templates through in vitro transcription and translation, bypassing the need for plasmid copying and propagation in bacterial hosts. This copying approach uses biotinylated amino acids during synthesis, enabling direct affinity purification without traditional cloning infrastructure, thereby reducing both time and cost.
Solution Approach 2:
The invention employs disposable in vitro transcription and translation reactions instead of reusable plasmid vectors. Each TF is synthesized de novo in a single-use reaction mixture containing biotinylated amino acids, eliminating the need for expensive plasmid construction, bacterial transformation, and culture maintenance, thus reducing overall manufacturing cost and time.
3Loss of information
If comprehensive surveys of TF binding sites across diverse species are conducted, then valuable regulatory information can be obtained, but the significant effort required limits high-throughput capability
Solution Approach 1:
The method achieves universality by using a standardized in vitro transcription and translation protocol that works across diverse species. The same biotin labeling and affinity purification approach can be applied to any TF from any organism, enabling high-throughput comparative studies without species-specific method optimizations, thus improving productivity while maintaining comprehensive information coverage.
Solution Approach 2:
The invention changes the fundamental parameters of TF production from in vivo plasmid-based expression to in vitro synthetic expression. This parameter change allows parallel processing of multiple TFs from different species using identical protocols, enabling high-throughput surveys while capturing comprehensive binding site information across diverse genomes.
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 approach significantly reduces the time and cost of producing TF binding site maps, enabling high-throughput surveys of TFs in diverse species, revealing conserved and divergent patterns of TF binding, and identifying new regulatory modules and motifs, while allowing for the characterization of gene regulatory networks across various organisms.
Implementation Method 1
The method employs a tRNA having an affinity-labeled amino acid, e.g., a lysine tRNA in which the lysine is linked to an affinity label, such as biotin
Implementation Method 2
The affinity moiety, e.g., biotin, allows for downstream affinity capture of TFs along with bound DNA sequences using a biotin binding agent, e.g., streptavidin, as a capture agent, e.g., using streptavidin-coated magnetic beads
Data Source
AI summary
Described herein are affinity-labeled polypeptide compositions, such as affinity-labeled transcription factor compositions, and methods of using such compositions to evaluate interactions of the polypeptide with other molecules such as nucleic acids.