Among the RXRs, Rxra is expressed rather ubiquitously, with higher levels in developing skin epidermis by late gestation [Dolle et al., 1994]. Rxrb is also expressed ubiquitously, and at low levels. Rxrg is expressed in all developing skeletal muscles. The functional significance of this expression is unclear, as the Rxrg-/- mouse mutants are viable and have no muscular defect, even in compound mutant combinations.
