The present invention relates to a porcine uroplakin II gene promoter, an
expression vector containing the promoter, and a method for producing
useful proteins using the vector. The promoter of the present invention
promotes the bladder-specific expression of a target protein at high
efficiency. An animal, which was transformed using the inventive promoter
so as to express the target protein, secretes the target protein in its
urine at high concentration, and the protein thus produced shows a
superior physiological activity to that of the same kind of the existing
protein. As a result, the inventive promoter, the expression vector and
transgenic animal using the promoter, can be advantageously used in the
production field of useful proteins that are medicinally valuable.