Rabbit β-globin complementary DNA (cDNA) has been inserted into SV40DNA in place of the gene coding for the virus' major capsid protein, VP1. The recombinant genome, SVGT5-RaβG, multiplies efficiently in CV1 monkey kidney cell cultures and is transcribed to yield cytoplasmic, polyadenylated hybrid mRNAs containing the β-globin coding sequence. Cells propagating SVGT5-RaβG produce substantial quantities of rabbit β-globin polypeptide.