C. Elegans Strain Responds to Blue Light

Creative BioMart uses the channelrhodopsin-2 (ChR2), a direct photogated cation channel from the green algae Chlamydomonas reinhardtii to construct C. Elegans strain which can responds to blue Light. By expressing the mutant ChR2 (GF):: YFP fusion protein, we can induce a strong response to blue light in excitable cells (muscles and neurons) of living and dissected Caenorhabditis elegans.

Technology Principle

In living, behavioral and anatomical animals, specific neurons or muscles expressing ChR2 can be activated rapidly and reversibly by light. In the excitable cells of Caenorhabditis elegans, light triggers specific behaviors. Channelrhodopsin is a 7-transmembrane helical protein, which is similar to light driven proton pump bacterial rhodopsin. In muscle cells, light activated ChR2 induces strong simultaneous contraction, which is reduced in the context of mutant L-type voltage-gated Ca²⁺ channel (VGCC) and ryanodine receptor (RyR).

Realize the Contraction of C. elegans Muscle Cells In Vivo

Muscle contraction is usually triggered by the gating of nicotinic acetylcholine receptors (nAChRs) and the resulting Na⁺ influx. Because Caenorhabditis elegans lacks voltage-gated Na⁺ channels, the action potential cannot be exerted. NAChR mediated depolarization directly causes contraction through the entry of voltage-gated Ca²⁺ channels (VGCC) and the resulting cytosolic Ca²⁺. ChR2 induced contraction should depend on Ca²⁺ influx directly through ChR2. And ChR2 mediated depolarization / VGCC activation.

ChR2 Activation in Mechanosensory Neurons Evokes Behavioral Responses

ChR2 can depolarize worm neurons. Simultaneous activation of all mechanoreceptor cells by ChR2 causes withdrawal. Since Caenorhabditis elegans avoids strong light, which is likely the result of (harmful) heat caused by light absorption, the analysis of light response becomes complex. Animals expressing ChR2 clearly showed a habit of light stimulation. Tap (and touch) response is also influenced by habit.

Workflow for Generating Optogenetic C. elegans Strains that Express ChR2

You provide the gene editing idea and we expertly design and deliver your transgenic animals within a few months.

Step	Description
Transgenic design	Selection of guide RNAs and/or design of donor homology plasmid or DNA oligonucleotide with special attention to codon usage, intron placement, and splicing.
Injections	Injection of mix into the C. elegans gonad.
Candidate screening	Initial screening. Identification of animals displaying selectable marker.
Strain confirmation	Confirmation of transgenic line(s). Screening of homozygous F2 animals via PCR and sequencing.

Creative BioMart is always devote us to provide high-quality and satisfactory service to our customers, if you are interested in our services or have some question, please feel free to contact us or make online inquiry.