STOCK Omp^{tm1.1(COP4*/EYFP)Tboz}/J

Stock number: 014173
Research areas: Neurobiology Research, Research Tools, Sensorineural Research

Description

These OMP-ChR2-YFP (OCY-58) knock-in mice express a ChR2(H134R)-EYFP fusion gene from the olfactory marker protein locus (Omp). As such, the ChR2(H134R)-EYFP fusion protein is expressed in all olfactory receptor neurons. This targeted mutation strain may be useful for studying olfactory transduction, olfactory circuitry, and olfactory perception by light stimulation.

Detailed description

These OMP-ChR2-YFP (OCY-58) mice express a ChR2(H134R)-EYFP fusion gene from the olfactory marker protein locus (Omp). Mice that are homozygous for the targeted mutation are viable, fertile, normal in size and do not display any gross physical or behavioral abnormalities. ChR2(H134R)-EYFP is expressed in all mature olfactory sensory neurons, rendering them light sensitive. Light directed at the olfactory epithelium or the glomeruli can elicit activity in mitral/tufted (M/T) cells of the olfactory bulb and can drive odor guided behavior. These mutant mice thus allow precise, timed delivery of stimuli input to the olfactory system. The Donating Investigator reports that this this targeted mutation creates a null allele. Due to possible olfactory deficits, analysis should be performed in heterozygous mice. The Donating Investigator recommends keeping the strain on the albino B6 background to avoid possible interference by pigmented melanocytes.

The ChR2(H134R)-EYFP fusion protein is composed of a Chlamydomonas reinhardtii-derived channelrhodopsin-2 that harbors a gain-of-function H134R substitution fused in-frame with an enhanced yellow fluorescent protein. The ChR2(H134R) is designed to cause larger stationary photocurrents compared to ChR2.

The bacterial opsins are retinal-binding proteins that combine a light-sensitive domain with an ion channel or pump; providing light-dependent ion transport, membrane potential alteration, and sensory functions to bacteria. This ChR2(H134R) functions as a blue light-driven cation channel that depolarizes the cell and causes action potentials. As such, illuminating ChR2(H134R)-expressing cells with blue light (450-490 nm) leads to rapid and reversible photostimulation of action potential firing activity in these cells.

Development

A targeting vector containing the ChR2(H134R)-EYFP fusion gene and a self-excising PGK-neo cassette, ACNF, was used to disrupt the targeted gene by replacing the coding sequence for Omp with ChR2(H134R)-EYFP coding sequence. The construct was electroporated into 129P2/OlaHsd-derived E14 embryonic stem (ES) cells. Correctly targeted ES cells were injected into recipient blastocysts, and chimeric animals were crossed to C57BL/6 mice. The resulting OMP-ChR2-YFP (OCY-58) mice were bred together to generate homozygotes. Upon arrival at The Jackson Laboratory Repository, the mice were crossed to albino C57BL/6J mice (B6(Cg)-Tyr^c-2J/J ; Stock No. 000058) for at least one generation to establish the colony. The Tyr^c-2J allele was bred out of the colony.

Allele

Symbol: Omp^{tm1.1(COP4*/EYFP)Tboz}
Name: targeted mutation 1.1, Thomas Bozza
MGI accession ID: MGI:5285648
Generation method: Targeted
Attributes: Reporter; Null/Knockout
Marker symbol: Omp
Marker name: olfactory marker protein
Chromosome: 7
Strain of origin: 129P2/OlaHsd
Expressed genes: COP4,Channelrhodopsin,Chlamydomonas
Site of expression: YFP is expressed in all mature olfactory sensory neurons.
Molecular note: A targeting vector containing the COP4/EYFP, a modified channel rhodopsin-2 gene from Chlamydomonas reinhardtii (ChR2(H134R), and enhanced yellow fluorescent protein fusion gene, and the a self-excising PGK-neo cassette, ACNF, was used to disrupt the targeted gene. The neo cassette removed itself.