Characterization of the promoters of the guinea pig neutrophil cationic peptide-1 and -2 genes.

Guinea pig neutrophils contain the antimicrobial cationic peptides GNCP-1 and GNCP-2 in the granules. To understand the regulation of the gene expression, the promoters for the GNCP-1 and GNCP-2 genes were characterized. Sequencing analysis of the genomic clones showed that the nucleotide sequences of the 5'-upstream regions (1.7 kb) from exon 1 were homologous (90-93%) between the GNCP-1 and GNCP-2 genes. However, transient transfection assays using luciferase reporter gene constructs revealed that the promoter activity of GNCP-1 was 2-fold greater than that of GNCP-2. Furthermore, DNase I footprint analysis demonstrated that three regions (I, II and III) were protected on the GNCP-1 promoter, whereas only two protected regions (II and III) were identified on the GNCP-2 promoter. Together these observations indicate that GNCP-1 and GNCP-2 are encoded by homologous genes, but the expression of the GNCP-1 and GNCP-2 genes is likely to be different at the level of transcription.