Cre Lox System
Cre Lox System - Related Videos
08:13
A Cre-Lox P Recombination Approach for the Detection of Cell Fusion In Vivo
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Cited by 11 •
2012
A method to track cell fusion in living organisms over time is described. The approach utilizes Cre-LoxP recombination to induce luciferase expression upon cell fusion. The luminescent signal generated can be detected in living organisms using biophotonic imaging systems with a sensitivity of detection of ˜1,000 cells in peripheral tissues.
10:29
Inducing Cre-lox Recombination in Mouse Cerebral Cortex Through In Utero Electroporation
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Cited by 6 •
2017
Cell-autonomous functions of genes in the brain can be studied by inducing loss or gain of function in sparse populations of cells. Here, we describe in utero electroporation to deliver Cre recombinase into sparse populations of developing cortical neurons with floxed genes to cause loss of function in vivo.
07:48
Protocols for Analyzing the Role of Paneth Cells in Regenerating the Murine Intestine using Conditional Cre-lox Mouse Models
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Cited by 3 •
2015
Intestinal epithelial stem cells (ISCs) are intermingled with Paneth cells. These cells are differentiated progeny of the ISC, which support the ISCs and provide antibacterial protection. Here we demonstrate how we used transgenic conditional mouse models to establish that Paneth cells play a crucial role in maintaining the intestinal epithelia.
07:22
A High-throughput Cre-Lox Activated Viral Membrane Fusion Assay to Identify Inhibitors of HIV-1 Viral Membrane Fusion
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Cited by 8 •
2018
We describe a cell-based assay to report on HIV-1 fusion via the expression of green fluorescent protein detectable by flow cytometry or fluorescence microscopy. It can be used to test inhibitors of viral entry (specifically at the fusion step) in cell-free and cell-to-cell infection systems.
02:45
Assessment of Viral Fusion Inhibitors Using a Cre-Inducible Fluorescent Reporter
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2026
Source: Esposito, A. M.,et al. High-throughput Cre-Lox Activated Viral Membrane Fusion Assay to Identify Inhibitors of HIV-1 Viral Membrane Fusion. J. Vis. Exp. (2018)This video demonstrates a co-culture fluorescent assay to monitor cell-to-cell viral transmission. The assay uses a red-to-green reporter cassette to visualize viral membrane fusion and evaluate the efficacy of test compounds in blocking viral entry.
FAQs
The relative orientation of paired loxP sites directs the kind of rearrangement that Cre catalyzes. When the sites are arranged to support excision, the intervening DNA is removed; another arrangement can produce inversion, whereas a suitable genomic configuration can enable exchange. This matters because the same recombinase can produce different genetic outcomes depending on loxP organization, allowing experimental design to match the intended DNA change.
Cre recombinase does not act on an arbitrary DNA segment; it recognizes paired loxP sequences and catalyzes recombination between them. Consequently, placing those sequences around a selected region determines which DNA lies within the rearrangement. This targeting principle lets researchers connect a chosen genetic alteration to a defined DNA configuration rather than producing nonspecific changes throughout the genome.
Tissue-specific Cre expression limits recombination to selected cell types or tissues, whereas inducible expression provides control over the circumstances in which Cre becomes active. The first strategy helps localize a genetic change, while the second makes activation conditional. Alongside loxP placement, these expression choices determine the biological context in which gene activation or removal can be studied.
Conditional knockouts and lineage tracing use the same recombination framework for different purposes. A conditional knockout focuses on removing a gene in selected cells, allowing investigators to examine gene function in that biological context. Lineage tracing focuses on tracking cell fate in a defined Cre-associated population, making it useful for studying development and changes in cellular identity. The distinction lies in the biological question being addressed.
A practical design matches a target DNA region containing paired loxP sequences with an appropriate Cre expression pattern. Researchers can use tissue-specific expression when the intended alteration is restricted to selected cells, or inducible expression when activation must depend on a defined condition. They then interpret the rearrangement in light of loxP orientation and genomic position, which determine whether the target is excised, inverted, or exchanged.
Cre Lox System experiments are especially valuable when a gene’s role depends on cell type, developmental setting, disease context, or cell fate. By restricting gene activation or removal to defined biological contexts, researchers can investigate gene function during development, examine disease mechanisms, and study changes in cell fate. The system therefore connects targeted DNA rearrangement with broader biological questions in living cells and organisms.