Somatic nuclear autoantigenic sperm protein (sNASP) is a human homolog of the N1/N2 family of histone chaperones. sNASP contains the domain structure characteristic of this family, which includes a large acidic patch flanked by several tetratricopeptide repeat (TPR) motifs. sNASP possesses a unique binding specificity in that it forms specific complexes with both histone H1 and histones H3/H4. ...

During nuclease treatment of nuclei in 80 mM buffers, a frequently used technique for solubilizing chromatin, oligonucleosomes escape the nucleus and are commonly discarded. These released oligonucleosomes lack H1 histone. Their loss of histone is easily explained by the recently described exchange of H1 that takes place at such ionic strengths. A comparison of H1-depleted nuclei to complete nu...

In addition to readily identifiable TATA and CAAT boxes, chicken H1 histone genes contain a highly conserved G-rich region at about minus 80 and an A-rich H1 histone gene-specific motif some 120 bases upstream from the H1 mRNA cap site. The level of transcription from wild-type, 'G-box' and 'A-box' H1 deletion mutant templates was tested in Xenopus oocytes and in HeLa cells. Removal of the H1 g...

Due to its net positive charge histone H1 readily associates with liposomes containing acidic phospholipids, such as phosphatidylserine (PS). Interestingly, circular dichroism reveals that while histone H1 in aqueous solutions appears as a random coil, its binding to liposomes containing PS is associated with a pronounced increase in alpha-helicity and beta-sheet content, estimated at 7% and 24...

Two forms of a histone H1-specific S-adenosylmethionine:protein-lysine N-methyltransferase (protein methylase III) have been purified from Euglena gracilis 48- and 214-fold, respectively, with yields of 3.4 and 4.6%. The enzymes were purified on DEAE-cellulose and histone-Sepharose affinity chromatography and found to be highly specific toward histone H1 as a substrate. However, one of the enzy...

Directed cell migration is a property central to multiple basic biological processes. Here, we show that directed cell migration is associated with global changes in the chromatin fiber. Polarized posttranslational changes in histone H1 along with a transient decrease in H1 mobility were detected in cells facing the scratch in a wound healing assay. In parallel to the changes in H1, the levels ...

HMGB1 is an architectural protein in chromatin, acting also as a signaling molecule outside the cell. Recent reports from several laboratories provided evidence that a number of both the intracellular and extracellular functions of HMGB1 may depend on redox-sensitive cysteine residues of the protein. In this study we demonstrate that redox state of HMGB1 can significantly modulate the ability o...

To analyze the mechanism by which histone H3 phosphorylation occurs specifically during mitosis, the effect of H1 on mitosis-specific H3 phosphorylation (Ser-10) was investigated in nucleosomes. H1 interaction with H1-depleted nucleosomes suppressed H3 phosphorylation including Ser-10 by approximately 50%. However, H1 interaction with DNA-free histone octamers failed to suppress H3 phosphorylat...

We generated mutant alleles of Drosophila melanogaster in which expression of the linker histone H1 can be down-regulated over a wide range by RNAi. When the H1 protein level is reduced to approximately 20% of the level in wild-type larvae, lethality occurs in the late larval - pupal stages of development. Here we show that H1 has an important function in gene regulation within or near heteroch...