Analyses of the induction of gene expressions by sonication and their signal transductions

We cloned DNA fragments containing promoter regions of cycloxigenase-2,flt-1,bmp-7 and c-fos genes that are involved in osteogenesis and linked to the luciferase gene, constructing gene cassettes. The gene cassettes were introduced into human osteoblast cells and sonicated with 1 MHz ultrasound at intensities of 0.1 to 0.5 W/cm^2, duty cycles of 5 to 10%, for 5 to 30 min. After incubation for 6 to 48 hrs, activations of the promoters were accessed. However, any induction of luciferase activity was confirmed including the cycloxigenase-2 promoter that previously showed induction after sonication in a similar condition.