C. elegans mec-4 Functional Gene Editing Service

Service Overview Precision editing of mec-4 in a premier genetic model for gentle touch sensation, mechanotransduction channel function and touch receptor neuron biology

mec-4 encodes MEC-4, a DEG/ENaC subunit that forms the pore of the mechanotransduction channel of the six touch receptor neurons in C. elegans. With MEC-10 it builds a trimer containing two MEC-4 and one MEC-10 subunit, and residue 713, the degeneration position, sets channel open probability.

Loss of function and gain of function give opposite outcomes here: a null leaves the neurons alive and merely touch insensitive, whereas a single substitution at Ala713 holds the channel open and kills the same cells. Specify which you need when ordering. CD BioSciences delivers custom mec-4 alleles — knockouts, defined point substitutions and tag knockins — with full genotype verification.

About the Target Gene: mec-4 Key biological and practical facts to inform your edit design

Gene symbol	mec-4 (a DEG/ENaC channel subunit that forms the ion pore of the touch receptor mechanotransduction channel)
Protein product	MEC-4 — DEG/ENaC pore-forming subunit of the touch receptor mechanotransduction channel
Mammalian homolog	the DEG/ENaC superfamily; the mammalian acid-sensing ion channels ASIC1 to ASIC4 (ACCN1 to ACCN3) and the amiloride-sensitive epithelial sodium channel subunits SCNN1A, SCNN1B and SCNN1G
Biological role	MEC-4 is the pore of the channel that converts skin deformation into a receptor current, and it carries the residue that gave the whole degenerin family its name. Working with MEC-10 it forms the native transduction complex, and single-molecule counting indicates a trimer containing two MEC-4 and one MEC-10 subunit. The instructive part of the protein is residue 713, an alanine, called the d or degeneration position. Substituting anything larger than cysteine there — valine in mec-4(e1611), threonine in mec-4(u231), aspartate in mec-4(u56) — increases macroscopic current, open probability and open time, consistent with steric hindrance holding the pore open. The aspartate variant has the highest resting open probability, around 0.76, and is the one variant that loses the response to shear stress, presumably because it is already open. The same substitutions also lower affinity for the blocker amiloride by a mechanism independent of side-chain size, and they make the channel toxic: the cells swell and degenerate.
Loss-of-function phenotype	Recessive loss of mec-4 causes touch insensitivity and nothing else obvious — the neurons survive, the 15-protofilament microtubules are normal, and the animal is otherwise healthy and coordinated. That is the opposite of the dominant d alleles at the same locus, which kill those very cells, so the two classes of allele produce opposite cellular outcomes and must not be treated as interchangeable.
Why edit it	It is the closest thing to a molecular handle on mechanotransduction gating available in a behaving animal: single-residue substitutions at position 713 give a graded series of open probabilities that can be read out both electrophysiologically and behaviourally. The locus is also the basis of a widely used cell-ablation reagent, since mec-4(d) expression kills cells and that toxicity requires mec-6, which makes ablation conditional on genetic background.
Recommended background	Standard N2 background, with the caveat that any d allele is dominant and causes visible neuronal swelling, so strains carrying one should be scored for cell death as well as for behaviour. Nulls are unremarkable to maintain; we suggest confirming cell survival by a mec-7-driven fluorescent marker so that a partial degeneration effect is not missed.
Representative allele	The three classical gain-of-function alleles mec-4(e1611) (A713V), mec-4(u231) (A713T) and mec-4(u56) (A713D), plus deletion nulls; custom CRISPR nulls, defined substitutions at position 713 installed by homology-directed repair, and tag knockins.

Fig. 1 MEC-4, the DEG/ENaC pore-forming subunit whose Ala713 degeneration position sets channel open probability in the C. elegans touch receptor mechanotransduction channel. The highlighted (amber) node marks the editing target.

mec-4 at a glance: mec-4 nulls lose touch sensitivity with neurons intact, while substitutions at residue 713 kill the same cells. Editing mec-4 alone is a powerful way to dissect MEC-4 function in vivo, with conserved relevance to human the DEG/ENaC superfamily; the mammalian acid-sensing ion channels ASIC1 to ASIC4 biology.

Our mec-4 Editing Strategies Choose the allele that matches your experimental question

Gene Knockout

gRNA-guided Cas9 cutting with NHEJ repair to introduce frameshift indels, generating premature stop codons and null / strong-loss-of-function mec-4 alleles.

Knockin & Tagging

Homology-directed repair (HDR) inserts GFP / HA / FLAG or other tags at the mec-4 locus for endogenous expression and subcellular localization studies.

Point Mutation

Introduce specific amino-acid substitutions to dissect functional domains and separate catalytic from scaffolding roles of MEC-4.

Conditional & Reporter Alleles

Build tissue-specific, inducible, or temperature-sensitive configurations and reporter lines for spatiotemporal analysis of MEC-4 function.

Decide first whether you want a loss or a toxic gain, because they are different orders. For loss, delete coding sequence and expect clean touch insensitivity with surviving neurons. For gain, install one of the 713 substitutions by homology-directed repair and expect cell death, which is dominant and depends on wild-type mec-6. A trap worth flagging explicitly: a frameshift ordered as a knockout and a knockin ordered as a degeneration model will both be described as mec-4 edits yet give opposite cellular outcomes, so state the residue change in the request. Because the d alleles are dominant, heterozygotes must be scored rather than assumed silent.

Workflow of Our mec-4 Editing Service From sequence to validated strain in a streamlined pipeline

Strategy Design

Define target (knockout / knockin / point mutation), select gRNA(s) and HDR template, confirm against the latest genome build.

gRNA Synthesis

Design, validate, and synthesize high-specificity guide RNAs targeting the mec-4 locus.

Vector & Template Construction

Build Cas9 / gRNA delivery construct and, for knockin, the homology-arm repair template.

Microinjection

Perform gonadal microinjection of N2 animals with CRISPR components and co-CRISPR selection markers.

Screening & Verification

PCR, Sanger / sequencing, and phenotype confirmation to isolate edited animals and verify alleles.

Delivery & Report

Provide homozygous / balanced mec-4 strains plus a full genotype and methods report.

Key Features Why researchers choose CD BioSciences for C. elegans editing

High-efficiency, optimized CRISPR / Cas9 platform for C. elegans.
Whole-process technical traceability and transparent timelines.
Flexible editing: knockout, knockin, tagging, and point mutation.
Full genotype verification before strain delivery.
One-stop model development integrated with our C. elegans portfolio.
Competitive pricing and short turnaround.
Direct access to scientists and prompt inquiry response.
Reliable, convenient global shipping of frozen stocks.

Applications Where a custom mec-4 model adds value

Pore-forming subunit of the touch receptor channel.
Gating of a DEG/ENaC channel by mechanical force.
Structure-function analysis of the degeneration position.
Amiloride and analogue block of sensory channels.
Ion-channel-mediated neurodegeneration.
Genetic cell ablation reagents.
Comparison with mammalian ASIC and ENaC channels.

Deliverables What you receive with every project

Genetically verified mec-4 edited strain(s) (homozygous or balanced).
Detailed genotyping report (editing strategy, allele sequence, verification data).
Methods summary and rearing / storage recommendations.
Optional: crosses into reporter, touch neuron GFP / mCherry marker, degenerin channel tag, and co-CRISPR selection backgrounds.
Optional: phenotype confirmation, ten-touch behavioural scoring, touch neuron morphology and 15-protofilament microtubule assessment, and channel puncta imaging.

Frequently Asked Questions

What type of mec-4 allele will I get from a knockout project?

Standard knockout projects deliver a frameshift indel allele predicted to produce a premature stop and a loss-of-function phenotype. We confirm the edit by sequencing and, where relevant, by characteristic phenotype assays.

Can you add a GFP or epitope tag to endogenous mec-4?

Yes. Using HDR with a designed repair template, we can insert GFP, HA, or FLAG tags at the C- or N-terminus while preserving endogenous promoter and regulation.

How long does a typical mec-4 editing project take?

Timelines vary with editing type and validation needs, but our optimized pipeline and co-CRISPR selection typically shorten turnaround versus conventional approaches. Contact us with your design for a project-specific estimate.

I want a mec-4 model. Should it be a knockout or a mec-4(d) allele?

They answer different questions and cannot substitute for one another. A knockout removes the pore subunit: the animal is touch insensitive, the six touch receptor neurons develop and survive normally, and there is no degeneration, so use this when the question is what the channel contributes to behaviour. A mec-4(d) allele does the reverse: a single amino acid change at Ala713 holds the channel open, sodium and calcium flood in, and the touch neurons swell and die, so the animal loses the cells as well as the response. Use this to model ion-channel-driven neurodegeneration, or to ablate chosen cells by driving the allele from a cell-specific promoter. Two practical notes: the d alleles are dominant, so heterozygotes show the phenotype, and their toxicity requires wild-type mec-6, which is what makes mec-4(d) usable as a conditional ablation reagent.

Start Your mec-4 Editing Project

CD BioSciences is committed to convenient, efficient, and cost-effective C. elegans model customization. Tell us your target design — knockout, knockin, tagging, or point mutation — and our scientists will respond with a tailored plan and quote.

References
1. Kim H. M., Colaiácovo M. P. CRISPR-Cas9-guided genome engineering in C. elegans. Current Protocols in Molecular Biology, 2016, 115(1): 31.7.1–31.7.18.
2. Brown A. L., Fernandez-Illescas S. M., Liao Z., Goodman M. B. Gain-of-function mutations in the MEC-4 DEG/ENaC sensory mechanotransduction channel alter gating and drug blockade. Journal of General Physiology, 2007, 129(2): 161–173.

For research use only.