Müller Cell-Specific Promoter for Targeted Gene Expression
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Solution Overview
Problem
Current gene expression systems for mammalian cells lack specificity and efficiency, particularly for targeting retinal cells, which is a challenge for studying neurodegenerative disorders, vision restoration, and drug discovery.
Innovation Solution
An artificial nucleic acid sequence specifically drives gene expression in Müller cells, utilizing a promoter that is operatively linked to a nucleic acid sequence with high identity, enabling targeted expression in Müller cells through an expression cassette or vector, such as a viral vector, for genes like photoreceptor molecules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If viral promoters such as CMV or SV40 are used to drive heterologous gene expression, then strong expression levels are achieved, but cell-type specificity is lost
Solution Approach 1:
The promoter is segmented into multiple functional modules: a core promoter element (CAG promoter from bovine growth hormone gene) providing strong basal transcription, and multiple upstream enhancer elements (Müller cell-specific elements at positions -42 to -56, -119 to -133, and -209 to -223) that confer cell-type specificity. This modular segmentation allows independent optimization of expression strength and specificity.
Solution Approach 2:
Different regions of the promoter have specialized functions: the core promoter region provides constitutive strong expression capability, while specific upstream regions contain Müller cell-specific regulatory elements that bind trans-acting factors (such as CRX, NRL, and other retinal transcription factors) to restrict expression to Müller cells. This local functional differentiation resolves the contradiction between strong expression and cell-type specificity.
2Adaptability or versatility
If cellular promoters from house-keeping genes are used, then endogenous regulatory elements are utilized, but expression strength and reliability are reduced compared to viral promoters
Solution Approach 1:
The promoter is a composite construct combining elements from different sources: the CAG promoter core from bovine growth hormone gene (providing strong viral-like expression) and multiple Müller cell-specific enhancer elements from endogenous retinal gene regulatory regions. This composite structure integrates the strengths of both viral promoters (strong expression) and cellular promoters (endogenous regulation compatibility and cell-type specificity).
Data Source
Figure 1
AI summary
The present invention provides an isolated nucleic acid molecule comprising, or consisting of, the nucleic acid sequence of SEQ ID NO:1 or a nucleic acid sequence of at least 400 bp having at least 80% identity to said sequence of SEQ ID NO:1, wherein said isolated nucleic acid molecule specifically leads to the expression in Müller cells of a gene when operatively linked to a nucleic acid sequence coding for said gene.