Caenorhabditis elegans ras-related protein rab-3 promoter
Caenorhabditis elegans rab-3 promoter, the 5' regulatory region of the rab-3 synaptic-vesicle GTPase gene. Drives pan-neuronal expression, active in nearly all neurons of the worm nervous system with minimal expression outside it. Widely used to drive reporter and effector transgenes broadly across the C. elegans nervous system.
Origin: Caenorhabditis elegans rab-3 gene, 5' upstream region
Characteristics
RAB-3 is a synaptic vesicle-associated Rab GTPase broadly expressed throughout the C. elegans nervous system; loss-of-function rab-3 mutants show impaired synaptic transmission and are partially depleted of synaptic vesicles. A transcriptional reporter combining 4.3 kb of rab-3 upstream sequence with the first rab-3 intron (rab-3prom1) is expressed in 99% (300 of 302) of adult neurons, the sole exception being the CAN neuron pair, making rab-3 a standard pan-neuronal reference promoter.
Applications: Used to drive reporter (GFP) and effector transgenes broadly across the C. elegans nervous system for pan-neuronal labeling, calcium imaging, optogenetics, and neuron-wide rescue or overexpression experiments, and as the reference standard against which other candidate pan-neuronal promoters are benchmarked.
Limitations: Not expressed in the CAN neuron pair, so it cannot label or manipulate this exception among otherwise pan-neuronal targets. The near-complete (99%) neuronal coverage was established for a reporter carrying 4.3 kb of upstream sequence plus the first intron; shorter upstream-only fragments, such as the 1.2 kb fragment in this record, may not fully recapitulate that coverage.