Pan-yeast ARS Sequence Optimization for Plasmid Stability
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Solution Overview
Problem
Current autonomously replicating sequences (ARS) for yeast are limited in functionality across different yeast species due to sequence diversity, leading to inefficient plasmid replication and loss during culture growth, making it difficult to use plasmid-based expression systems across various yeast species.
Innovation Solution
A 452 bp DNA sequence from Kluyveromyces lactis has been identified and modified with 1 to 17 mutations to create a synthetic ARS that functions stably across multiple yeast species, including Saccharomyces cerevisiae, Pichia pastoris, and others, by optimizing the nucleotide sequence within the core functional region to enhance plasmid replication and maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If current ARS modules are used in yeast species, then plasmid replication can occur in a subset of yeasts, but the ARS function is limited and plasmid replication efficiency is low leading to plasmid loss during culture growth
Solution Approach 1:
The patent creates a universal ARS module that functions across multiple yeast species (S. cerevisiae, P. pastoris, K. lactis, and others) by combining conserved functional elements from different species-specific ARS sequences. This multi-functional design allows a single ARS construct to serve as a replication origin in diverse yeast hosts, resolving the contradiction between species adaptability and replication efficiency.
Solution Approach 2:
The patent optimizes the ARS sequence by modifying nucleotide parameters including GC content, dinucleotide frequency, and core element composition to enhance replication efficiency. Specific parameter adjustments were made to the ARS consensus sequence to improve plasmid maintenance while maintaining functionality across different yeast species.
2Reliability
If species-specific ARS sequences are used, then ARS function is maintained in the native species, but the ARS rarely works in other yeast species
Solution Approach 1:
The patent develops a universal ARS module that maintains reliable function in the native species while gaining the ability to function in other yeast species. This is achieved by incorporating conserved functional elements from multiple species-specific ARS sequences, creating a hybrid ARS that is adaptable across yeast diversity while maintaining replication reliability.
Solution Approach 2:
The patent constructs a composite ARS sequence by combining functional elements from different species-specific ARS sequences. This composite design integrates conserved motifs and structural features from S. cerevisiae, P. pastoris, K. lactis, and other yeasts, creating a chimeric ARS that functions reliably across species boundaries.
3Productivity
If lower efficiency replication origins are used, then plasmid replication occurs, but plasmid loss occurs during culture growth
Solution Approach 1:
The patent optimizes replication origin parameters including GC content, dinucleotide frequency, and core element composition to enhance replication efficiency. These parameter adjustments ensure high-frequency plasmid replication while maintaining plasmid stability during culture growth, preventing plasmid loss.
Solution Approach 2:
The patent employs iterative testing and optimization of ARS sequences based on observed plasmid stability and replication efficiency. Through multiple rounds of sequence modification and experimental validation, the ARS module was refined to achieve both high replication productivity and stable plasmid maintenance in yeast cultures.
Data Source
AI summary
A DNA sequence that functions as an origin in many different yeast species. From 1 to 17 mutations can be introduced into this sequence to improve its function across multiple yeasts. The resulting synthetic DNA sequence confers stable plasmid replication function in all yeast species tested, including but not limited to Saccharomyces cerevisiae, Lachancea kluyveri, Kluyveromyces lactis, Kluyveromyces wickerhammii, Hansenula polymorpha, and Pichia pastoris. Also provided are sequences that function as an optimal origin in the industrially useful Pichia pastoris.