Structure and expression of neutrophil gelatinase cDNA. Identity with type IV collagenase from HT1080 cells

Abstract

Neutrophils synthesize and store intracellularly a 92-kDa type IV collagenase (gelatinase), the primary structure of which is unknown. We designed a primer based on the highly conserved cysteine-switch region of metalloproteinases and employed the polymerase chain reaction to generate a probe of the human neutrophil gelatinase (HNG) gene. This probe was used to clone the cDNA encoding HNG by screening a chronic granulocytic leukemia cDNA library. In vitro translation of the cDNA-derived HNG mRNA yielded a major product of 78 kDa and smaller autolytically activated or degraded products, all of which were recognized by anti-HNG antibody. The HNG cDNA sequence is nearly identical to that encoding a 92-kDa gelatinase secreted by HT1080 cells. In addition, primer extension and S1 analysis reveal that the above two gelatinase transcripts have similar initiation sites. The HNG cDNA hybridized to a 2.8-kilobase mRNA from chronic granulocytic leukemia cells. HNG mRNA expression was absent from uninduced HL60 cells and from HL60 cells induced to granulocytic maturation with Me2SO. However, unlike other neutrophil secondary granule genes, HNG mRNA was detected in HL60 cells induced to monocytic maturation with 12-O-tetradecanoylphorbol 13-acetate. This suggests that the HNG gene may be subject to differential control pathways in two related but distinct hematopoietic lineages.