Bordetella bronchisepticadermonecrotizing toxin stimulates protein synthesis in an osteoblastic clone, MC3T3-E1 cells

The effects of Bordetella bronchiseptica dermonecrotizing toxin on protein synthesis in an osteoblastic clone, MC3T3-E1 cells, were investigated. The rate of protein synthesis in the serum-starved cells was increased by the toxin after a latent period of about 4 h, and reached 2.5 times that of the control 24 h after addition of toxin. The toxin raised the level of protein synthesis even in actively proliferating cells. The stimulatory effect of the toxin on protein synthesis occurred earlier than other toxic events so far reported, such as the stimulation of DNA synthesis and the inhibition of osteoblastic differentiation, and was apparently dependent on the toxin concentrations over the range 0.05 ng ml-1 to 6.0 ng ml-1. Therefore, the stimulatory effect of the toxin on protein synthesis could be useful in determining the mode of action of the toxin.