Engineered Reverse Transcriptase Variants for Single-Cell mRNA Capture
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Solution Overview
Problem
Existing nucleic acid sequencing technologies struggle to accurately characterize and attribute genetic material from small populations or individual cells within a sample, leading to majority bias and inaccurate expression data due to ensemble processing methods and geometric amplification, which favor majority constituents over minority components.
Innovation Solution
The use of engineered reverse transcription enzymes with specific mutations and truncations, combined with microfluidic partitioning of cells into discrete compartments, allows for the reverse transcription and sequencing of nucleic acids from individual cells or small groups, enabling accurate attribution and high-throughput analysis of minority cell populations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ensemble processing methods and geometric amplification are used, then high-throughput sequencing is achieved, but majority bias occurs and minority cell populations are inaccurate
Solution Approach 1:
The invention partitions cells into discrete microfluidic compartments (droplets or wells) before nucleic acid processing. Each compartment contains individual cells or small groups, physically separating them to prevent ensemble averaging. This segmentation enables subsequent high-throughput processing of many individual cells while maintaining the ability to attribute genetic material to specific cells, thereby resolving the contradiction between high-throughput capability and accuracy for minority populations.
2Quantity of substance
If reverse transcription is performed in small reaction volumes, then single-cell analysis is enabled, but enzyme activity and stability are reduced
Solution Approach 1:
The invention introduces specific amino acid mutations in reverse transcriptase enzymes (e.g., mutations at positions 69, 139, 200, 302, 306, 313, 330, 435, 448, 449, 454, 524, 603, 607) that enhance thermal stability and activity. These parameter changes at the molecular level allow the enzyme to maintain high reliability and activity even in the extremely small reaction volumes (picoliter to nanoliter scale) required for single-cell analysis, thus resolving the contradiction between small volume and enzyme performance.
3Measurement precision
If full-length transcript capture is improved, then accurate gene expression data is obtained, but susceptibility to cell lysate inhibition increases
Solution Approach 1:
The invention employs engineered reverse transcriptase variants with specific amino acid substitutions that confer enhanced resistance to cell lysate components. These parameter changes in enzyme structure allow the enzyme to maintain high full-length transcript capture efficiency even in the presence of inhibitory substances released during cell lysis, thereby resolving the contradiction between transcript capture accuracy and lysate resistance.
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 enhances the ability to capture full-length transcripts, resist cell lysate, and maintain thermal stability, while providing high activity in small reaction volumes, thus improving the characterization of nucleic acids from individual cells and small groups, reducing bias and increasing accuracy.
Implementation Method 1
engineered reverse transcription enzymes... to reverse transcribe said RNA molecule to a complementary DNA molecule
Data Source
AI summary
Disclosed herein, are compositions, methods, and kits comprising engineered reverse transcription enzymes that exhibit several desired properties such as thermal stability, processive reverse transcription, non-templated base addition, and template switching ability. The engineered reverse transcription enzymes described herein demonstrate unexpectedly higher resistance to cell lysate inhibition, greater ability to capture full-length mRNA transcripts, and demonstrate improved results in small reaction volumes as compared to other engineered reverse transcription enzymes.