MAR Sequence Expression Vector for Animal Cells
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Solution Overview
Problem
Current expression vectors for animal cells do not efficiently express foreign genes, particularly due to position effects and methylation of inserted DNA, leading to variability in transgene expression.
Innovation Solution
Incorporating at least one copy of a human β-globin MAR sequence at the 3′ terminal of a transcription terminator in an expression vector, which enhances gene expression by protecting inserted DNA from neighboring chromatin effects and reducing methylation, with further enhancement when two copies are used.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a MAR sequence is inserted into a host genome to increase transgene expression, then expression level increases, but position effects from neighboring chromatin enhancer or silencer still affect expression variability
Solution Approach 1:
The patent introduces MAR sequences as intermediary elements that mediate between the transgene and the chromatin environment. These MAR sequences act as protective buffers that insulate the transgene from position effects, thereby reducing expression variability while maintaining high expression levels
Solution Approach 2:
The patent changes the structural parameters of the expression vector by incorporating MAR sequences at specific positions (5′ terminal of promoter and/or 3′ terminal of transcription terminator). This structural modification alters the interaction between the transgene and chromatin, transforming the expression pattern from position-dependent to position-independent
2Stability of the object's composition
If multiple MAR sequences are sequentially introduced at the 3′ terminal of a transcription terminator, then expression stability increases, but vector structure complexity increases
Solution Approach 1:
The patent segments the MAR sequence element into discrete copies that can be independently inserted at the 3′ terminal of the transcription terminator. By using multiple separate copies rather than a single complex element, the patent achieves enhanced stability while keeping the structural modification modular and manageable
Data Source
AI summary
Provided are an expression vector for an animal cell including a promoter, a cloning site or a polynucleotide encoding foreign product, and a transcription terminator, all of which are operably connected each other within the expression vector, in which at least one copy of human β-globin MAR sequence is attached to the 31 terminal of the transcription terminator, and a method of expressing a foreign gene using the expression vector.