Histone chaperones are critical for guiding specific post-transcriptional modifications of histones, safeguarding the histone deposition (or disassociation) of nucleosome (dis)assembly, and regulating chromatin structures to change gene activities. HAT1-interacting factor 1 (Hif1) has been reported to be an H3-H4 chaperone and to be involved in telomeric silencing and nucleosome (dis)assembly. ...

Histone post-translational modifications play an important role in regulating chromatin structure and gene expression in vivo. Extensive studies investigated the post-translational modifications of the core histones H3 and H4 or the linker histone H1. Much less is known on the regulation of H2A and H2B modifications. Here, we show that a major modification of H2B in Drosophila melanogaster is t...

Seed dormancy is defined as the failure of a viable seed to germinate under favorable conditions. Besides playing an adaptive role in nature by optimizing germination to the most suitable time, a tight control of dormancy is important in crop plants. Extensive genetic and physiological studies have identified the involvement of several factors, but the molecular mechanisms underlying this proce...

The site of in vitro ADP-ribosylation of histone H2B was determined. From chromatin of rat liver incubated with [ribose(NMN)-14C]NAD (210 pCi), the histone H2B fraction was extracted with acid and purified by column chromatographies on Bio-Gel P-60 and Sephadex G-150. The final preparation (96 mg of protein), which consisted of ADP-[*4C]ribosylated (1.8 pCi) and nonADP-ribosylated histone H2B’s...

Nap1 is a histone chaperone involved in the nuclear import of H2A-H2B and nucleosome assembly. Here, we report the crystal structure of Nap1 bound to H2A-H2B together with in vitro and in vivo functional studies that elucidate the principles underlying Nap1-mediated H2A-H2B chaperoning and nucleosome assembly. A Nap1 dimer provides an acidic binding surface and asymmetrically engages a single H...

Histone H3 of nucleosomes positioned on active genes is trimethylated at Lys36 (H3K36me3) by the SETD2 (also termed KMT3A/SET2 or HYPB) methyltransferase. Previous studies in yeast indicated that H3K36me3 prevents spurious intragenic transcription initiation through recruitment of a histone deacetylase complex, a mechanism that is not conserved in mammals. Here, we report that downregulation of...

The highly charged histone N-terminal domains are engaged in inter- and intra-nucleosomal interactions, and contain a host of sites used for posttranslational modification. We have studied the effect of deleting residues 30-37 from the N-terminal domain of histone H2B in yeast cells, on nucleotide excision repair (NER) following UV irradiation, as these cells are quite sensitive to UV. We find ...

Several sulphated polysaccharides have been shown to block the infection of T-cells by the human immunodeficiency virus (HIV)-l [1,2]. Dextrin-2-sulphate (D2S) is a synthetically sulphated polysaccharide which inhibits infection of human T-cell lines by a variety of HIV-1 cell-free isolates [3]. Although its mechanism of action has not been established, this compound appears to prevent HIV-1 in...