Zebrafish 503-bp unc-45b (503unc) promoter
Zebrafish unc-45b myosin chaperone gene promoter (503 bp); drives skeletal- and cardiac-muscle-specific reporter expression in Danio rerio, recapitulating the endogenous unc-45b pattern across adaxial, fast, cardiac, cranial, fin, and trunk muscle (Berger and Currie 2013). Used for compact muscle-targeted transgene expression in zebrafish models of muscle disease.
Origin: Danio rerio unc-45b gene
Characteristics
In stable Tg(503unc:GFP) zebrafish, the fragment drives GFP first in adaxial cells and their slow-fiber descendants, then in fast muscle fibers; at later stages expression is robust throughout cardiac, cranial, fin, and trunk muscle, closely matching the endogenous unc-45b expression domain (Berger and Currie 2013).
Applications: Used for compact, muscle-restricted reporter and transgene expression in zebrafish models of skeletal and cardiac muscle disease and studies of sarcomeric myosin folding, where the small promoter size leaves more room for the payload in size-constrained vectors (Berger and Currie 2013).
Limitations: Restricted to skeletal and cardiac muscle; not suited for targeting other tissues. Unlike a further-truncated 195 bp core fragment derived from the same unc-45b upstream region, the 503 bp 503unc fragment itself has not been reported to be heat-shock inducible (Rudeck et al. 2016), so temporal control requires pairing with a separate inducible system.
Sequence
References
- Rudeck et al. (2016). A compact unc45b-promoter drives muscle-specific expression in zebrafish and mouse. Genesis - Rudeck 2016 unc45b Compact Promoter