Disease relevance of Hist1h1b

• In contrast, two differentiated (endoderm-like) cell lines derived from teratocarcinomas lack H1b, and one also lacks H1d [1].
• Digestion of the two proteins with Staphylococcus aureus V8 protease gives identical peptide maps (sharing no common peptides with those of histones H1A or H1B), which indicates that the induced protein qualifies as H1 [2].
• The embryonal carcinoma cells had a ratio of H1A/H1B of 1.49 or greater [3].
• The possible change due to dexamethasone treatment in the relative amounts of two major subtypes of H1 histone, H1A and H1B, in mouse myeloid leukemia cells (M1 cells) during differentiation was examined [4].

High impact information on Hist1h1b

• In HEK293, dissociating the H1b/c-IP(3)R complex with H1a results in TRPC3 translocation to the PM, where it is spontaneously active [5].
• To form aggregates with the histones H1t and H1b, however, greater amounts of protein were required [6].
• As for the histone subtype H1b, we found a dissociation constant of 8-16 nM to a single mononucleosome (210 base pairs), whereas the binding constant of all other subtypes varied between 2 and 4 nM [6].
• Here we investigated the relationship between phosphorylation of H1b and transcription [7].
• Histone H1b phosphorylation is dependent upon ongoing transcription and replication in normal and ras-transformed mouse fibroblasts [7].

Biological context of Hist1h1b

• However, the amount of H1a and H1b phosphorylations was negligible [8].
• They also show that neither H1b nor H1d is essential for cell division [1].
• MSX1 cooperates with histone H1b for inhibition of transcription and myogenesis [9].
• By investigating Msx1 function in repression of myogenic gene expression, we identified a physical interaction between Msx1 and H1b, a specific isoform of mouse histone H1 [9].
• Indirect immunofluorescent studies show that phosphorylated H1b is localized in centers of RNA splicing in the nucleus, suggesting that this modified H1 subtype is complexed to transcriptionally active chromatin [10].

Anatomical context of Hist1h1b

• Furthermore, in the quiescent fibroblasts, the synthesis of H1a and H1b was preferentially reduced [11].
• We found that Msx1 and H1b bind to a key regulatory element of MyoD, a central regulator of skeletal muscle differentiation, where they induce repressed chromatin [9].
• In additional assays of morphogenesis, i.e., cell sandwiching between two collagen gels or culture on a thick layer of Matrigel (a laminin-rich extracellular matrix), all clones form epithelial-cell lined cavitary structures, except H1B cells which are unable to generate lumina under these conditions [12].

Associations of Hist1h1b with chemical compounds

• The serine residue was replaced by threonine residue in H1a, and H1b did not have a homologous peptide [8].
• In glutamate-induced responses, HTk cells exhibited slower time-dependent decay kinetics than H1b cells [13].
• H1A and H1B histone variants extracted with 5% perchloric acid were methionine-free [14].
• The relative amount of H1B decreased after dexamethasone treatment and reached about one-tenth that of H1A at the fully differentiated stage [4].

Other interactions of Hist1h1b

• Two of the genes that have not been assigned previously to the five somatic H1 subtypes have been identified as encoding the H1b and H1d subtypes [15].
• Two others, H1d and H1e, are present in a second patch, while the H1b gene is at least 500 kb away in a patch containing 14 core histone genes [15].
• Expression patterns of H1.1 to H1.5 and H1(o) were determined in tissues of animals at days 5, 9 and 20 after birth and of adult mice [16].
• Moreover, Msx1 and H1b cooperate to inhibit muscle differentiation in cell culture and in Xenopus animal caps [9].
• Under these experimental conditions the histone H1 variants H1b and H1c obtained from mitotic enriched NIH 3T3 fibroblasts and isolated by reversed-phase high-performance liquid chromatography were clearly separated in their non-phosphorylated and different phosphorylated forms [17].

Analytical, diagnostic and therapeutic context of Hist1h1b

• 9. Partial peptide mapping of gel purified H1A and H1B suggest the two proteins differ in primary structure [3].

References