Mutant Sox Proteins Enhance Oct4 Binding for Cell Reprogramming
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Solution Overview
Problem
Current methods for inducing pluripotency in differentiated cells are limited, with only a few proteins capable of reprogramming, and the biochemical uniqueness of these proteins remains unexplained, particularly as Sox2 can induce pluripotent stem cells but Sox17 cannot despite binding to similar DNA sequences.
Innovation Solution
Mutated Sox7 and Sox17 proteins are engineered to resemble Sox2, with specific amino acid mutations that enhance their ability to bind to Oct4, allowing them to induce pluripotency in partially or fully differentiated cells by forming cooperative interactions on specific DNA motifs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If Sox17 is used to induce pluripotency, then the cell reprogramming capability is improved, but the ability to bind and cooperate with Oct4 on canonical motifs is insufficient
Solution Approach 1:
The patent applies parameter changes by mutating specific amino acid residues in Sox17 (and Sox7) to alter their biochemical properties. The mutations E122K in Sox17 and E99K in Sox7 change the charge and interaction characteristics of these proteins, enabling them to bind Oct4 with higher affinity and cooperate on canonical motifs, thereby resolving the contradiction between reprogramming capability and binding reliability
Solution Approach 2:
The patent uses copying by transferring specific amino acid sequences from Sox2 to Sox17 and Sox7. The mutated regions in Sox17 and Sox7 are designed to resemble the corresponding regions in Sox2, which naturally has high affinity for Oct4. This copying of the functional interface allows Sox17 and Sox7 to acquire Sox2-like binding capabilities while maintaining their identity
2Productivity
If multiple amino acid mutations are introduced to enhance Oct4 binding, then the pluripotency induction efficiency is improved, but the protein structure complexity increases
Solution Approach 1:
The patent applies local quality by introducing mutations only in specific localized regions of the Sox proteins - namely the DNA-binding domain and protein-protein interaction interface. Rather than globally complicating the protein structure, the mutations are concentrated in key functional areas (such as residues 88-108 in Sox7 and 111-131 in Sox17), allowing enhanced Oct4 binding without unnecessary overall structural complexity
Solution Approach 2:
The patent uses partial action by introducing a limited number of specific point mutations rather than comprehensive structural modifications. The mutations are focused on critical residues that directly contact Oct4 or DNA, achieving significant functional improvement with minimal changes to the overall protein architecture
Data Source
AI summary
There is presently provided mutant Sox2, Sox7 and Sox17 proteins that have acquired or increased ability to induce pluripotency in a partially differentiated or fully differentiated cell. Sox7 and Sox17 are mutated to resemble in part Sox2, or Sox2 is mutated to resemble in part Sox7 or Sox17. In one aspect, the Oct4 contact interface of Sox7 or Sox17 is mutated. In another aspect, the high mobility group (HMG) of Sox2 is fused to the C-terminal activation domain of Sox7 or Sox17. Methods relating to inducing pluripotency using a mutant Sox2, Sox7 or Sox17 protein are also provided.