A NOVEL MEMBER, PC7, OF THE MAMMALIAN KEXIN-LIKE PROTEASE FAMILY - HOMOLOGY TO PACE4A, ITS BRAIN-SPECIFIC EXPRESSION AND IDENTIFICATION OF ISOFORMS

By polymerase chain reaction (PCR) with primers corresponding to the s equences of catalytic domain conserved among the mammalian kexin-like protease family, a cDNA fragment encoding a novel member of the family was obtained from rat pituitary. A cDNA for the novel protease was ob tained from three overlapping clones isolated from a rat pituitary cDN A library using the PCR product as a screening probe. The protein, des ignated as PC7, encoded by this cDNA contained a putative activation s ite with the sequence RXKR, subtilisin-like catalytic domain and a hom e B region which are typical of mammalian kexin-like proteases, and sh ort cysteine-rich region at the carboxyl-terminal end. It exhibited su rprising sequence similarity to PACE4A. The PC7 transcript was express ed at high levels in the brain. However it was undetectable in the liv er, kidney, heart, and spleen. The presence of PC7 isoforms (PC7A and PC7B) was also shown. (C) 1994 Academic Press, Inc.