Effect of dioxin on the gene promoters

Effect of dioxin and other polychlorinated polyaromatic compounds on mammal ian gene's expression is reviewed. The attention is focused on molecular me chanisms of gene promoter activation. We describe first the classical dioxi n activation pathway: activation of aryl hydrocarbon receptor (AhR) by diox in agonists, the association of activated AhR with "Aromatic hydrocarbon re ceptor nuclear translocator" (Arnt) and the activation by this dimer of the response elements of several genes. We then discuss the interaction of pro teins implicated in AhR activation such as hsp90 and Arnt in the cross talk with other cellular regulatory pathways. Action of polychlorinated polyaro matic compounds on genes by mechanisms not involving "dioxin receptor" is a lso examined.