Further characterization of the murine collagenase (type IVB) gene promoter and analysis of mRNA expression in murine tissues

The collagenase B type IV (Co14B) gene is highly expressed in the osteoclast, the primary bone-resorbing cell. However, factors that regulate expression of the Co14B gene are not well characterized. A murine P1 genomic clone containing a 94 kb sequence insert which contains the Co14B gene was isolated. A 4 kb EcoR1 DNA fragment containing the 5' flanking sequence of the gene was further subcloned and restriction mapped. Putative transcription factors such as SRY, Lyf-1, and GATA1 and 2, binding motifs were identified by sequence analysis in this promoter region. Enhancer and suppressor regions were mapped by transient expression of Co14B gene promoter deletion mutant-luciferase reporter gene constructs in HepG2 cells. Co14B mRNA expression in different murine tissues was analyzed by reverse transcription-polymerase chain reaction and demonstrated high levels of expression in bone, clavaria, spleen and thymus. This promoter provides a valuable tool for targeting gene expression to the osteoclast.