Prothymosin alpha binds to histone H1 in vitro.

Previous studies have shown that prothymosin alpha (ProT alpha) is a nuclear acidic protein implicated in cell proliferation. To identify proteins that interact with ProT alpha we have used ligand-blotting assays. We report here that purified ProT alpha binds specifically to histone H1 in a dose dependent manner. Polyglutamic acid, an analog of the central acidic domain of ProT alpha, strongly inhibits the above interaction, suggesting that the binding of ProT alpha to histone H1 is mediated through its acidic domain.