Human-origin tumor cell proliferation inhibiting factor

摘要

A DNA fragment coding for a novel human-origin tumor cell proliferation inhibiting factor can be obtained from a cDNA library originating in human colonic cancer cells by using a DNA fragment coding for a mouse-origin tumor cell proliferation inhibiting factor as the DNA probe. It is possible to secrete a novel human-origin tumor cell proliferation inhibiting factor out of the cells by constructing an expression plasmid containing a promoter originating in Bacillus brevis, a signal peptide originating in Bacillus brevis and, downstream thereof, a DNA fragment coding for said novel inhibiting factor, transforming Bacillus brevis by using the above plasmid, and culturing the transformant thus obtained. Thus the novel proliferation inhibiting factor can be efficiently produced. IMAGE