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...

Keratinocytes (KCs) may play important roles for maintenance of peripheral tolerance in the upper layers of the skin. Coinhibitory signals mediated via the programmed death (PD)-1 and its ligand B7-H1 (PD-L1/CD274) are crucial for the downregulation of T cell immune responses and for the maintenance of peripheral tolerance. In this study, to investigate the role of KC-expressed B7-H1 in the reg...

The structural requirements for DNA/RNA hybrids to be suitable substrates for RNase H1 are well described; however the tolerance level of this enzyme towards modifications that do not alter the duplex conformation is not clearly understood, especially with respect to the sense RNA strand. In order to investigate the molecular requirements of Escherichia coli RNase H1 (termed RNase H1 here) with...

BACKGROUND The discovery that genetic alterations in oncogenes and tumour suppressor genes accompany tumour formation in many human tumours has encouraged the search for genes that promote or suppress tumour spread and metastasis; nm23 is a promising candidate for a metastasis suppressing gene. AIMS To evaluate whether expression of nm23-H1 protein or loss of heterozygosity (LOH) of the nm23-...

Neuronal stimulation leads to immediate early gene (IEG) expression through calcium-dependent mechanisms. In recent years, considerable attention has been devoted to the transcriptional responses after neuronal stimulation, but relatively little is known about the changes in chromatin dynamics that follow neuronal activation. Here, we use fluorescence recovery after photobleaching, biochemical ...