Caenorhabditis elegans myosin heavy chain A (myo-3) promoter
Caenorhabditis elegans myo-3 promoter, the 5' regulatory region of the body wall muscle myosin heavy chain A gene. Drives strong, body wall muscle-restricted expression throughout larval and adult development. Used to target reporter and effector transgenes specifically to body wall muscle in transgenic C. elegans.
Length: 2500 bp
Strength: strong
Tissue: Body wall muscle exclusively; not expressed in pharyngeal muscle or neurons
Expression: constitutive
Origin: Caenorhabditis elegans myo-3 gene, 2.5 kb 5' upstream region
Characteristics
Low-copy-number transgenic arrays carrying the myo-3 genomic locus rescue myo-3 loss-of-function mutants and reproduce the endogenous body wall muscle expression and myofilament assembly pattern, establishing that myo-3 regulatory sequences are sufficient for correct tissue-specific expression. Three separable elements confer body wall muscle enhancer activity - two lie within the 2.5 kb upstream of the myo-3 ATG (myo-3 transcripts are trans-spliced) and a third lies within the first myo-3 intron.
Applications: Used to drive reporter (GFP, lacZ) and effector transgene expression specifically in C. elegans body wall muscle, for studying muscle development, myofilament assembly, and neuromuscular disease models, and to rescue body wall muscle myosin mutants in transgenic rescue experiments.
Limitations: Restricted to body wall muscle - does not drive expression in pharyngeal muscle (use myo-2) or neurons (use rab-3). A first-intron enhancer element contributes to full activity, so promoter-only reporter fusions that exclude the first intron may underrepresent native expression levels.
