Live Viral DNA Imaging Using OR-GFP and ANCH3 Labeling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for detecting HIV-1 genomes after reverse transcription are invasive, destroy the morphological context, and are not compatible with electron microscopy or immune fluorescence approaches, limiting the study of HIV-1 preintegration complex morphogenesis and viral integration sites distribution.
Innovation Solution
A non-invasive system using the ANCHOR3 technology, which integrates the OR-GFP cDNA into the HIV-1 genome under the control of a CMV promoter, allowing real-time detection of retro-transcribed viral DNA in live cells, including primary cells and CD4+ T cells, using fluorescence imaging compatible with electron microscopy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If FISH is used to detect HIV-1 integration sites, then detection capability is improved, but morphological context is destroyed
Solution Approach 1:
The patent introduces an intermediary fluorescent labeling system that bridges viral genome detection and morphological preservation. The system uses a lentiviral vector expressing OR-GFP that binds to ANCH3 sequences in the viral genome, serving as a mediator that enables detection while maintaining cellular morphology for correlative microscopy
Solution Approach 2:
The patent replaces the mechanical/chemical processing of FISH with a biological expression system. Instead of using fluorescent probes that require harsh sample preparation, the system uses cellular expression of OR-GFP protein that naturally binds to viral DNA, substituting a gentle biological process for a destructive chemical process
2Measurement precision
If EdU incorporation is used to detect viral genomes, then detection capability is improved, but specificity deteriorates due to host genome incorporation
Solution Approach 1:
The patent applies local quality by making the labeling system specific to viral genomes only. The OR-GFP protein is engineered to bind exclusively to ANCH3 sequences that are artificially inserted into the viral genome, creating a localized and specific labeling event that does not occur in host cell DNA
Solution Approach 2:
The patent introduces OR-GFP as a specific intermediary that mediates between the viral genome and detection system. This intermediary protein provides high specificity by only binding to its cognate ANCH3 sequence, eliminating the non-specific background problem of EdU incorporation into host DNA
3Measurement precision
If invasive detection methods are used, then detection capability is improved, but cell survival deteriorates
Solution Approach 1:
The patent implements self-service by engineering the viral vector to autonomously produce its own detection marker. The lentiviral vector contains the OR-GFP expression cassette, enabling the infected cell to self-label its viral genome without external intervention, thereby avoiding invasive detection procedures
Solution Approach 2:
The patent replaces invasive mechanical detection methods with a gentle biological self-labeling process. The cellular expression system substitutes for harsh fixation and probing procedures, allowing live-cell imaging and long-term tracking without compromising cell viability
4Measurement precision
If multiple detection systems are used, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple detection capabilities into a unified system. The lentiviral vector simultaneously delivers the viral genome and the OR-GFP expression cassette, combining genome delivery and detection functions into a single integrated platform that reduces overall system complexity
Solution Approach 2:
The patent creates a universal detection platform that can track viral genomes across different cell types and experimental conditions. The OR-ANCH3 system serves multiple functions including live-cell imaging, fixed-cell detection, and correlative microscopy, replacing the need for multiple specialized detection systems
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
Enables the visualization of early steps of HIV-1 infection in live cells, facilitates drug screening, and allows structural studies through correlative microscopy, while preserving cell viability and morphology.
Implementation Method 1
The OR protein specifically interacts with Anch3 sequences
Implementation Method 2
OR-GFP cDNA was cloned in the lentiviral vector pFlap under the control of the CMV promoter
Data Source
AI summary
A recombinant lentiviral vector comprising a coding sequence for an OR protein fused to a coding sequence for a fluorescent protein or a subunit of a fluorescent protein, and a promoter active in human cells operatively linked to the coding sequences. A recombinant lentivirus comprising a recombinant genome comprising an RNA that generates an ANCH sequence upon retrotranscription. A recombinant eukaryotic cell comprising a genomically integrated DNA copy of the recombinant lentiviral vector. A method of observing lentiviral DNA in a eukaryotic cell, comprising: providing a recombinant eukaryotic cell that produces a fusion protein comprising an OR protein, fused to a fluorescent protein or a subunit of a fluorescent protein; infecting the recombinant eukaryotic cell with a recombinant lentivirus comprising a recombinant genome comprising an RNA that generates an ANCH sequence upon retro-transcription, under conditions sufficient for reverse transcription of the recombinant lentiviral genome comprising an ANCH sequence; allowing the OR protein to bind to the ANCH sequence; and detecting the fluorescent protein or subunit of the fluorescent protein to thereby observe the lentiviral DNA in the eukaryotic cell. This tool can be suitable also for in vivo applications (e.g. humanized mice) as well as for screening of new antiretroviral compounds. The HIV-1 ANCHOR system can be extended to the study of other viruses or for the screening of antiviral compounds, e.g. against SARS-CoV2.