Point mutations were introduced in the cDNA sequence which transformed the amino acids residues at positions 148-149 from Leu-Pro to Ser-Thr. The modified cDNA sequence was then fused to the start codon of exon 1 along with IRES, a neomycin resistance gene and a polyadenylation sequence. It is predicted that the resulting product would not be cleavable to release the soluble form of the protein. (J:86547)