DNA replication involves the chromatin assembly on new DNA strands which involves the formation of new nucleosomes, the basic unit of chromatin. Nucleosome is composed of the tetramer of H3/H4 histones and two dimers of histones H2A/ H2B that are wrapped around with DNA segment [1,2]. H3/ H4 and H2A/H2B histones are called core histones as they are positioned in the center of nucleosome. Some c...

We engineered a photoactivatable system for rapidly and reversibly exporting proteins from the nucleus by embedding a nuclear export signal in the LOV2 domain from phototropin 1. Fusing the chromatin modifier Bre1 to the photoswitch, we achieved light-dependent control of histone H2B monoubiquitylation in yeast, revealing fast turnover of the ubiquitin mark. Moreover, this inducible system allo...

Histone proteins are synthesized in large amounts during S-phase to package the newly replicated DNA, and are among the most stable proteins in the cell. The replication-dependent (RD)-histone mRNAs expressed during S-phase end in a conserved stem-loop rather than a polyA tail. In addition, there are replication-independent (RI)-histone genes that encode histone variants as polyadenylated mRNAs...

Reconstituted complexes of DNA with histone were prepared by salt-and-urea step gradient dialysis. The DNA was complexed with histone H1, with the combination of the other four histones H2A, H2B, H3 and H4, and with whole histones. These DNA-histone complexes were purified by Bio-Gel column chromatography, and the weight ratio of histone-to-DNA was determined in each complex. The thermal denatu...

The case is described of a 73 year old man who presented with a lupus-like syndrome related to treatment with isoniazid and had IgG antinuclear antibodies against the nucleo-histone complex (H2A-H2B)-DNA. After a short course of treatment with prednisone and discontinuation of isoniazid the patient's lupus symptoms resolved and a gradual decrease in antibodies to (H2A-H2B)-DNA occurred. This ca...

We have measured the concentration dependence of the osmotic pressure for solutions of core histones in 2.0 M NaC1, pH 8.0, over the concentration range from 1 to 20 mg/ml at 25°C. The ratio of the osmotic pressure to the protein concentration is nearly constant over this range, with a value corresponding to an apparent number average molecular weight of 75,000. Gel filtration of a typical core...

Unlike other metazoan mRNAs, replication-dependent histone gene transcripts are not polyadenylated but instead have a conserved stem-loop structure at their 3' end. Our previous work has shown that under certain conditions replication-dependent histone genes can produce alternative transcripts that are polyadenylated at the 3' end and, in some cases, spliced. A number of microarray studies exam...

A model for chromatin structure is presented. (a) Each of four histone species, H2A (IIbl or f2a2), H2B (IIb2 or f2b), H3 (III or f3) and H4 (IV or f2al) can form a parallel dimer. (b) These dimers can form two tetramers, (H2A)2(H2b)2 and (H3)2(H4)2. (C) These two tetramers bind a segment of DNA and condense it into a "C" segments. (d) The adjacent segments, termed extended or "E" segments, are...

D1, a nonhistone chromosomal protein rich in both basic and acidic amino acids, has been localized at a limited number of specific loci in polytene chromosomes of Drosophila melanogaster. H2B, a nucleosomal histone, and H1, a nonnucleosomal histone, are both found throughout most chromosomal regions.

Background: During the later stages of spermatogenesis, spermatid nuclear remodeling and condensation are associated with histone modifications and the sequential displacement of histones by transition proteins and then by protamines. In humans, approximately 15% of the sperm DNA remains packaged by histones in sequence-specific areas. The histone variant H2B, member W, testis-specific (H2BFWT)...