POLY(ADP-RIBOSE) BINDING-PROPERTIES OF HISTONE H1 VARIANTS

Using a poly(ADP-ribose) binding assay on protein blots we examined th e ability of rat testis histone H1 variants to establish non-covalent interactions with the polymer. All the H1 variants bound ADP-ribose po lymers; the binding was salt resistant and highly specific, occurring even in the presence of a large excess of competitor DNA. A comparison among the H1 variants showed that Hit has the highest affinity for po ly(ADP-ribose). Long and branched poly(ADP-ribose) molecules were foun d to be preferentially involved in the interaction with the histone va riants. The results further corroborate the concept that non-covalent interactions of poly(ADP-ribose) with target proteins may constitute a n important mechanism to modulate chromatin structure. (C) 1998 Elsevi er Science B.V. All rights reserved.