Abstract: A DNA construct wherein a DNA fragment which is recombinable in yeast chromosomal DNA is directly or indirectly linked at both ends of a DNA fragment which comprises a pair of R sensitive sequences oriented in the same direction and flaking both an R gene placed under the control of an inducible promoter and an expressible selective marker gene, which is a DNA construct designed with the R sensitive sequences non-symmetrically shortened, so that no functionable R sensitive sequence remains after the R sensitive sequence recombination has occurred by expression of the R gene and the selective marker has been removed. Since no functionable R sensitive sequence remains after removal of the selective marker, recombination does not occur again, and thus the same selective marker may be used for multiple insertions of foreign genes.

Abstract: The present invention relates to a DNA fragment having a promoter activity of PHO81 gene regulating the production of phosphatase, and which is obtainable from Saccharomyces cerevisiae.; a DNA fragment bearing a structural gene downstream from the above PHO81 promoter; a transformant containing a DNA fragment bearing the above PHO81 promoter; a transformant containing a DNA fragment bearing the above PHO81 promoter and a structural gene downstream from the PHO81 promoter; and a process for obtaining a gene product which includes culturing a transformant containing a DNA fragment bearing the above PHO81 promoter and a structural gene located downstream therefrom in a suitable medium until the gene product is formed and recovering the gene product from the culture. Pharmacologically important proteinous materials may be efficiently produced with the use of the above-described novel and potent promoter obtained from yeast which is a eukaryotic microorganism.