H1 histone somatic variants from L929 mouse fibroblasts were purified by reverse-phase HPLC. We analysed the ability of each H1 histone variant to allow the H1-H1 interactions that are essential for the formation of the higher levels of chromatin structure, and we investigated the role played by the poly(ADP-ribosyl)ation process. Cross-linking analysis showed that H1e is the only somatic varia...

The approximation-solvability of a generalized system of nonlinear variational inequalities (SNVI) involving relaxed pseudococoercive mappings, based on the convergence of a system of projection methods, is presented. The class of relaxed pseudococoercive mappings is more general than classes of strongly monotone and relaxed cocoercive mappings. Let K1 and K2 be nonempty closed convex subsets o...

We have reconstituted salt-treated SV40 minichromosomes with differentially phosphorylated forms of histone H1 extracted from either G0-, S- or M-phase cells. Sedimentation studies revealed a clear difference between minichromosomes reconstituted with S-phase histone H1 compared with histone H1 from G0- or M-phase cells, indicating that the phosphorylation state of histone H1 has a direct effec...

Linker histones are involved in the formation of higher-order chromatin structure and the regulation of specific genes, yet it remains unclear what their principal binding determinants are. We generated a genome-wide high-resolution binding map for linker histone H1 in Drosophila cells, using DamID. H1 binds at similar levels across much of the genome, both in classic euchromatin and heterochro...

A number of studies have suggested B7-H1, a B7 family member, inhibits T cell responses. Therefore, its expression on nonlymphoid tissues has been proposed to prevent T cell-mediated tissue destruction. To test this hypothesis, we generated transgenic mice that expressed B7-H1 on pancreatic islet beta cells. Surprisingly, we observed accelerated rejection of transplanted allogeneic B7-H1-expres...

The effects of H1-receptor blocking agents, pyrilamine, promethazine, and diphenhydramine, on the amplitude and time course of endplate potentials (e.p.ps) were studied in the sartorius muscles of frogs. H1-receptor blockers (10(-5)-10(-4) M) reduced the amplitude of e.p.ps recorded intracellularly without affecting the resting membrane potential. The acetylcholine potential was decreased by pe...

Linker histones such as H1 are abundant basic proteins that bind tightly to nucleosomes, thereby acting as key organizers of chromatin structure. The molecular details of linker histone interactions with the nucleosome, and in particular the contributions of linker DNA and of the basic C-terminal tail of H1, are controversial. Here we combine rigorous solution-state binding assays with native g...

Histone H1 is highly phosphorylated in transcriptionally active, amitotic macronuclei of Tetrahymena during vegetative growth. However, the level of H1 phosphorylation changes dramatically in response to different physiological conditions. H1 is hyperphosphorylated in response to heat shock and during prezygotic stages of conjugation. Conversely, H1 is largely dephosphorylated during prolonged ...

A new procedure is described for the reassociation of histone H1 to rat liver polynucleosomes selectively depleted of H1 and nonhistone proteins. The fidelity of reconstitution was scrutinized by nuclease digestion and sedimentation studies monitoring the regeneration of structural features which disappear following removal of H1. The results demonstrate that the 166-base pair barrier of digest...