ISOLATION AND CHARACTERIZATION OF THE CDNA FOR MOUSE NEUTROPHIL COLLAGENASE - DEMONSTRATION OF SHARED NEGATIVE REGULATORY PATHWAYS FOR NEUTROPHIL SECONDARY GRANULE PROTEIN GENE-EXPRESSION

A characteristic of normal neutrophil maturation is the induction of s econdary granule protein (SGP) mRNA expression. Several leukemic human cell lines mimic normal morphologic neutrophil differentiation but fa il to express Sops, such as lactoferrin (LF) and neutrophil gelatinase (NG). In contrast, two murine cell lines (32D C13 and MPRO) are able to differentiate into neutrophils and induce expression of LF and No. Therefore, to study the normal regulation and function of these genes, the corresponding murine homologs must be isolated. Using cDNA repres entational difference analysis (RDA) to compare a committed myeloid pr ogenitor cell line (EPRO) with the multipotent stem cell line from whi ch it was derived (EML), we isolated a fragment bearing homology to hu man neutrophil collagenase (hNC). Here, we describe the cloning and ch aracterization of a full-length (similar to 2 kb) clone that exhibits nearly 65% nucleotide and 73% amino acid identity to hNC. Ribonuclease protection analysis (RPA) of the tissues and cell lines shows that mo use NC (mNC) is expressed only in cell lines exhibiting neutrophilic c haracteristics, further confirming its identity as the mouse homolog o f hNC. Furthermore, we have demonstrated a shared negative regulatory pathway for this and other Sop genes. We have previously shown that CC AAT displacement protein (CDP/cut) binds to a specific region of the L F promoter, and overexpression of CDP blocks G-CSF-induced upregulatio n of LF gene expression in 32D C13 cells. We show here that in these c ells, upregulation of both NC and NG is also blocked. CDP is thus the first identified transcription factor that is a candidate for mediatin g the shared regulation of neutrophil SGP protein genes. (C) 1998 by T he American Society of Hematology.