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

Abstract The collagenase B type IV (Col4B) gene is highly expressed in the osteoclast, the primary bone-resorbing cell. However, factors that regulate expression of the Col4B gene are not well characterized. A murine P1 genomic clone containing a 94 kb sequence insert which contains the Col4B 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 Col4B gene promoter deletion mutant-luciferase reporter gene constructs in HepG2 cells. Col4B 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 targeing gene expression to the osteoclast.