Enables DNA-binding transcription activator activity, RNA polymerase II-specific. Involved in white fat cell differentiation. Acts upstream of or within adipose tissue development; fat cell differentiation; and positive regulation of transcription by RNA polymerase II. Located in nucleus. Is expressed in several structures, including forelimb bud; hindlimb phalanx; limb mesenchyme; oral epithelium; and telencephalon ventricular layer. Orthologous to human CREB5 (cAMP responsive element binding protein 5). [provided by Alliance of Genome Resources, Apr 2022]