C. elegans unc-25 Functional Gene Editing Service

Service Overview Precision editing of unc-25 in a premier genetic model for synaptic transmission, neurotransmitter release and receptor signalling

unc-25 encodes UNC-25, glutamic acid decarboxylase, the enzyme that converts glutamate to GABA. It is the only GAD in the C. elegans genome, so it supplies all GABA for roughly 26 GABAergic neurons, most of them inhibitory motor neurons.

Without UNC-25 there is no detectable GABA in the animal, yet the neurons develop and connect normally. The result is the characteristic shrinker phenotype, in which touch contracts dorsal and ventral body-wall muscle at once because cross-inhibition is missing. CD BioSciences delivers custom unc-25 alleles — knockouts, catalytic point mutants and tag knockins — with full genotype verification.

About the Target Gene: unc-25 Key biological and practical facts to inform your edit design

Gene symbol	unc-25 (glutamic acid decarboxylase, the single enzyme that synthesises GABA from glutamate)
Protein product	UNC-25 — glutamic acid decarboxylase (GAD), the GABA synthesis enzyme
Mammalian homolog	GAD1 (GAD67) and GAD2 (GAD65); UNC-25 is roughly 45% identical to mammalian GAD and is the only GAD in the worm genome
Biological role	GABA is made in one step: glutamate decarboxylation by GAD. In mammals that job is split between GAD67, which supplies most cytosolic GABA, and GAD65, which is tuned to deliver GABA for vesicular filling. C. elegans does not split it — unc-25 is the single GAD, so one gene carries both roles. Around 26 neurons contain GABA immunoreactivity, almost all of them motor neurons: the DD and VD inhibitory motor neurons of the ventral cord, RME head motor neurons, RIS, and the AVL and DVB enteric motor neurons, plus GABAergic input to vulval and uterine muscle. Their job is cross-inhibition: when one side of the body contracts, GABA released onto the contralateral body-wall muscle lets the other side relax, turning a stiff tube into a moving one. Beyond acute motor control, GABA signalling from the DD neurons also sets the tempo of their own developmental remodelling, and loss of unc-25 slows removal of the ventral synapses laid down in the larva.
Loss-of-function phenotype	unc-25 loss-of-function animals contain no detectable GABA by immunostaining and their extracts lack measurable GAD activity, so the phenotype is a clean chemical depletion rather than a partial reduction. The classic behavioural signature is the shrinker phenotype: touch produces simultaneous contraction of dorsal and ventral body-wall muscle instead of coordinated relaxation, because the inhibitory half of the motor circuit is silent. The animals are viable and fertile, which is what makes the locus experimentally comfortable, and their motor neurons develop and wire up normally — the defect is in the transmitter, not in the circuit diagram. Ablation-free and pharmacology-free, this is the cleanest way to remove inhibition while leaving anatomy intact.
Why edit it	UNC-25 is the cleanest single-gene entry into inhibitory transmission anywhere in the animal kingdom: knock out one gene and GABA is gone, with no compensation from a paralogue. Because the downstream components are conserved (UNC-47 is SLC32A1/VGAT, UNC-49 is a GABA-A-type receptor), the whole synthetic-load-release-detect module maps directly onto the vertebrate inhibitory synapse. If you are modelling GABA deficiency, testing compounds that act on GABA metabolism, or using GABA as a tool to silence defined neurons in a behaving animal, this is the locus that gives you a definable starting point rather than a partial knockdown.
Recommended background	N2 (wild type). Nulls are viable and fertile and the phenotype is unambiguous, so this is a low-risk locus for both knockouts and tags. We recommend confirming each new allele by GABA immunostaining alongside a shrinker assay, since the two together distinguish a true synthesis defect from a downstream transport or receptor problem.
Representative allele	Classical loss-of-function alleles from the CGC collection plus engineered deletion alleles; custom CRISPR nulls, catalytic-domain point mutants that separate decarboxylase activity from any protein-interaction role, and GFP / HA / FLAG tag knockins available on request.

Fig. 1 UNC-25, the glutamic acid decarboxylase that converts glutamate to GABA in C. elegans GABAergic motor neurons and supplies the transmitter loaded by UNC-47 for inhibitory signalling onto body-wall muscle. The highlighted (amber) node marks the editing target.

unc-25 at a glance: unc-25 loss removes all detectable GABA and produces the shrinker phenotype without disturbing neuron development. Editing unc-25 alone is a powerful way to dissect UNC-25 function in vivo, with conserved relevance to human GAD1 biology.

Our unc-25 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 unc-25 alleles.

Knockin & Tagging

Homology-directed repair (HDR) inserts GFP / HA / FLAG or other tags at the unc-25 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 UNC-25.

Conditional & Reporter Alleles

Build tissue-specific, inducible, or temperature-sensitive configurations and reporter lines for spatiotemporal analysis of UNC-25 function.

A straight deletion is usually the right first allele here, because the whole point of UNC-25 is the chemistry rather than a scaffolding function, and the null is unambiguous and viable. If you want finer resolution, a catalytic-domain point mutant separates decarboxylase activity from localisation and is a good control against the possibility that the protein itself plays a structural role in GABAergic terminals. Pair whichever allele you choose with an anti-GABA immunostaining step at validation, so that loss of the transmitter is demonstrated directly rather than inferred.

Workflow of Our unc-25 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 unc-25 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 unc-25 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 unc-25 model adds value

GABA biosynthesis from glutamate.
Cross-inhibition in the ventral cord motor circuit.
The shrinker phenotype as a readout of inhibitory loss.
Developmental remodelling of DD motor neurons.
Single-GAD systems versus split GAD67/GAD65 roles.
GABA metabolism in ethanol and drug-response assays.
Conserved GABA-A-type receptor signalling.

Deliverables What you receive with every project

Genetically verified unc-25 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, glutamatergic / GABAergic / cholinergic neuron marker, and co-CRISPR selection backgrounds.
Optional: phenotype confirmation, aldicarb and levamisole resistance assays, electrophysiological recording at the neuromuscular junction, and locomotor / habituation analysis support.

Frequently Asked Questions

What type of unc-25 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 unc-25?

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 unc-25 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.

How does unc-25 differ from unc-47, and which one should I edit?

They are two different steps and the comparison is diagnostically useful. UNC-25 synthesises GABA from glutamate; UNC-47 is the vesicular transporter that then pumps cytosolic GABA into synaptic vesicles. The telling distinction is the direction of the immunostaining change: unc-25 mutants have no detectable GABA at all, whereas unc-47 mutants accumulate elevated GABA immunoreactivity in their cell bodies because synthesis continues but loading fails. If your question is about transmitter supply, edit unc-25; if it is about vesicular filling or quantal loading, edit unc-47. Running both in parallel cleanly separates synthesis from packaging.

Start Your unc-25 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. Jin Y., Jorgensen E., Hartwieg E., Horvitz H. R. The Caenorhabditis elegans gene unc-25 encodes glutamic acid decarboxylase and is required for synaptic transmission but not synaptic development. Journal of Neuroscience, 1999, 19(2): 539–548.

For research use only.