The present invention provides a DNA fragment exhibiting a potent promoter activity when used in the yeast. The present invention relates to a DNA fragment possessing a transcription promoter activity of the yeast, said DNA fragment having a whole of the DNA sequence shown by SEQ ID NO: 1 or a portion of said DNA sequence inclusive of its 3'-end, or having a DNA sequence which is hybridizable to a sequence complementary to a whole of the DNA sequence shown by SEQ ID NO: 1 or to a portion of said DNA sequence inclusive of its 3'-end and maintains the transcription promoter activity of said whole or portion of the DNA sequence shown by SEQ ID NO: 1; an expression plasmid containing a recombinant DNA fragment comprising said DNA fragment and a gene coding for a heterologous protein positioned downstream of said DNA sequence; a host cell transformed with said recombinant DNA fragment or said expression plasmid; and a method for preparing a heterologous protein which comprises culturing said host cell and recovering the heterologous protein from the culture. According to the present invention, a potent promoter usable in a heterologous gene expression system with the yeast as a host is provided.