Humanized IL-6 Locus Replacement for Regulated Mouse Expression
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Solution Overview
Problem
Mice transgenic for human IL-6 gene exhibit poorly regulated expression leading to various pathologies such as plasmacytosis and glomerulonephritis, limiting their usefulness.
Innovation Solution
Genetically modified non-human animals with human IL-6 and/or humanized IL-6 receptor genes expressed under endogenous murine promoter and regulatory elements, replacing endogenous IL-6 and/or IL-6 receptor loci to avoid pathologies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If human IL-6 transgene is randomly inserted into mouse genome, then human IL-6 expression is achieved, but pathologies such as plasmacytosis and glomerulonephritis occur
Solution Approach 1:
The patent extracts the harmful effect of random insertion by using targeted insertion methods. The human IL-6 transgene is inserted at a specific, pre-selected locus in the mouse genome rather than allowing random integration. This targeted approach removes the harmful element (uncontrolled expression) while preserving the desired function (human IL-6 production).
Solution Approach 2:
The patent applies preliminary action by selecting and preparing a specific genomic locus before insertion. The target locus is pre-identified and prepared with appropriate flanking sequences and regulatory elements, ensuring that the human IL-6 transgene will be expressed in a controlled manner from the outset, preventing pathologies before they can develop.
2Power
If human IL-6 transgene is expressed at high levels, then therapeutic effect is enhanced, but severe pathologies develop
Solution Approach 1:
The patent applies local quality by using tissue-specific or locus-specific regulatory elements to control IL-6 expression. Different regions of the genome have different regulatory characteristics, and the patent leverages this by placing the human IL-6 transgene at a locus with appropriate local regulatory properties that enable controlled, high-level expression without systemic toxicity.
Solution Approach 2:
The patent changes the regulatory parameters of the transgene by incorporating specific promoter sequences, enhancers, and locus control regions. These parameter modifications allow the human IL-6 transgene to achieve high expression levels while maintaining temporal and spatial control, preventing the uncontrolled expression that leads to pathologies.
3Reliability
If endogenous mouse IL-6 locus is replaced with human IL-6 gene, then human IL-6 expression is achieved with proper regulation, but mouse-specific functions are lost
Solution Approach 1:
The patent applies segmentation by dividing the IL-6 gene into functional segments and selectively replacing only the necessary portions. The human IL-6 coding sequence is inserted while retaining mouse regulatory elements and genomic context, allowing human protein production with mouse-specific expression control, thus maintaining mouse biological functions.
Solution Approach 2:
The patent creates a composite genetic construct that combines human IL-6 coding sequence with mouse regulatory elements and genomic architecture. This composite approach produces a chimeric gene system that expresses human protein while operating within mouse biological frameworks, preserving mouse-specific functions while achieving humanized expression.
Data Source
AI summary
Mice that comprise a replacement of endogenous mouse IL-6 and/or IL-6 receptor genes are described, and methods for making and using the mice. Mice comprising a replacement at an endogenous IL-6Rα locus of mouse ectodomain-encoding sequence with human ectodomain-encoding sequence is provided. Mice comprising a human IL-6 gene under control of mouse IL-6 regulatory elements is also provided, including mice that have a replacement of mouse IL-6-encoding sequence with human IL-6-encoding sequence at an endogenous mouse IL-6 locus.