The invention provides a synthesis-inducible eucaryotic promoter having a transcriptional
activity comprising, for example, a heavy metal-sensitive DNA sequence, derived
from a natural promotor, of a base sequence of any one of SEQ ID NOS: 1 to 4; an
inducer of the transcriptional activation activity thereof; a recombinant expression
vector comprising a site for the insertion of an extraneous gene ligated to the
above promotor: a eucaryotic expression kit comprising eucaryotic cells transfected
with the above vector and the above inducer; and a method for expression of an
extraneous gene in a eucaryotic system by using the same
