Osteoblast-Specific Nuclear Targeting Sequence for DNA Import
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current gene therapy methods face challenges in efficiently transferring DNA into osteoblast lineage cells due to cellular barriers, particularly the nuclear envelope being impermeable to large nucleic acid molecules, lacking specific nuclear import signals, and the lack of identified sequences for targeting these cells.
Innovation Solution
A polynucleotide sequence from the human type I alpha 2 procollagen gene promoter region, referred to as the osteoblast-specific nuclear targeting sequence, is used to facilitate the transport of nucleic acids into the nuclei of osteoblast lineage cells, overcoming the nuclear entry barrier without the need for cell division.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If non-viral plasmid vectors or linear DNA molecules are used for gene therapy delivery, then the method avoids viral safety issues, but the efficiency of DNA transfer into osteoblast nuclei remains very low due to nuclear envelope impermeability
Solution Approach 1:
The patent uses an osteoblast-specific nuclear localization signal (NLS) peptide as an intermediary mediator. This peptide binds to the plasmid DNA and facilitates its transport across the nuclear envelope into osteoblast nuclei. The NLS peptide acts as a bridge between the DNA cargo and the nuclear import machinery, enabling efficient nuclear entry without viral vectors while maintaining safety.
Solution Approach 2:
The patent modifies the physical-chemical parameters of the DNA delivery system by conjugating plasmid DNA with osteoblast-specific NLS peptides. This chemical modification changes the DNA's ability to interact with nuclear import machinery, transforming it from a molecule that cannot cross the nuclear envelope to one that can efficiently enter osteoblast nuclei.
2Productivity
If DNA is delivered to all cells within tissue using conventional methods, then delivery is achieved, but gene expression is not cell-specific and DNA cannot be efficiently imported into osteoblast nuclei
Solution Approach 1:
The patent applies local quality by using osteoblast-specific nuclear localization signals that are only recognized and bound by nuclear import machinery in osteoblasts. This means the same plasmid DNA construct will be imported into nuclei only in cells expressing the specific import machinery (osteoblasts), while being excluded from other cell types, achieving cell-specific gene expression through localized recognition.
Solution Approach 2:
The osteoblast-specific NLS peptide serves as a cell-type-specific intermediary. It mediates the interaction between plasmid DNA and the nuclear import machinery only in osteoblasts, where the specific import proteins are expressed. This selective mediation ensures DNA is imported only into osteoblast nuclei, achieving precise cell-specificity.
3Stability of the object's composition
If the nuclear envelope is used as a barrier to prevent DNA entry, then nuclear integrity is maintained, but DNA cannot traverse the cytoplasm intact to reach the nucleus
Solution Approach 1:
The patent introduces an osteoblast-specific NLS peptide as an intermediary that enables DNA to traverse the nuclear envelope without compromising its integrity. The peptide binds to DNA in the cytoplasm and recruits nuclear import machinery, facilitating transport through nuclear pore complexes while the nuclear envelope remains intact and functional.
Solution Approach 2:
The patent replaces the mechanical barrier function of the nuclear envelope with a biochemical recognition system. Instead of relying on physical disruption or passive diffusion, the system uses specific molecular recognition between the NLS peptide and nuclear import proteins to actively transport DNA through the envelope, maintaining its structural integrity while enabling efficient import.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This sequence enables efficient and specific nuclear entry of nucleic acids into osteoblasts, allowing for targeted gene expression and therapeutic applications in bone-related disorders by directing nucleic acids into osteoblast nuclei with high efficiency, exceeding 40% in non-dividing cells.
Implementation Method 1
specific polynucleotide sequences that facilitate nuclear entry have been identified... these sequences have only been successful at targeting entry into the nucleic of certain types of non-dividing cells
Data Source
AI summary
A plasmid, viral or linear DNA molecule containing a nucleic acid sequence derived from the promoter region of the hCol1α2 gene, which is selectively transported into the nuclei of cells in the osteoblast lineage. The sequence can be used independently as a nuclear entry sequence only, and/or as a nuclear entry sequence without regard to position, in a vector or linear DNA that directs gene expression and nuclear entry. The disclosure further includes a chimeric DNA sequence derived by the addition of osteoblast-specific enhancer sequences to the nuclear entry sequence/promoter sequence, to increase osteoblast-specific expression while retaining osteoblast-specific nuclear import. An enhancer sequence is derived from the promoter region of the human Core Binding Factor alpha 1 (Cbfa1/Runx2) gene. The Cbfa1/Runx2 promoter can be added to the sequence derived from, or alternatively, comprising the promoter region of the hCol1α2 gene. Also provided are methods of use of the novel sequences.