That signalling pathways, particularly the mitogen-activated protein kinase cascades, elicit modification of chromatin proteins such as histone H3 by phosphorylation and/or acetylation concomitant with gene activation is now well established. The picture that is emerging is one of a complex and dynamic pattern of multiple modifications at the H3 tail. Here, we review the inducible gene systems where H3 modifications have been reported and re-evaluate the controversy as to the kinase(s) that phosphorylates it as well as the proposed coupling between H3 phosphorylation and acetylation.