High impact information on Hist1h1a

• Homer's action depends on its ability to crosslink and is blocked by the dominant-negative immediate early gene form, H1a [1].
• Disruption of this interaction by mutagenesis or antisense strategies, or expression of endogenous Homer1a (H1a), induces constitutive activity in mGluR1a or mGluR5 [2].
• Mammalian somatic cells contain a set of H1 linker-histone subtypes, H1 (0) and H1a to H1e, that bind to nucleosome core particles and to the linker DNA between nucleosomes [3].
• In HEK293, dissociating the H1b/c-IP(3)R complex with H1a results in TRPC3 translocation to the PM, where it is spontaneously active [4].
• Analysis of germ cell chromatin from H1t null mice showed that other H1 subtypes, especially the testis-enriched HIST1H1A, herein denoted as the H1a subtype, were able to compensate for the absence of H1t to maintain a normal total H1 to nucleosome core ratio [5].

Biological context of Hist1h1a

• The linker histone subtype H1.1 belongs to the group of main-type histones and is synthesized in somatic tissues as well as in germ cells during the S-phase of the cell cycle [6].
• However, the amount of H1a and H1b phosphorylations was negligible [7].
• The linker histone subtypes H1.1 and H1t are expressed at high levels in meiotic and early haploid cells [8].
• It is remarkable that the single amino acid substitution of Thr-152 with glutamic acid was almost as effective as the truncation of the C terminus to amino acid 151 in destabilizing histone H1.1 binding in vivo [9].
• The aim of this work was to answer the question whether H1t can be replaced during spermatogenesis by H1.1 or H1 [10].

Anatomical context of Hist1h1a

• H1.1 mRNA was found at high concentrations in thymus and spleen throughout development and in testis beginning with a low expression in 5-day-old animals and increasing levels in testis RNA from 9- and 20-day-old and adult mice [11].
• A decline in H1a was observed also in cultured mouse embryo fibroblasts after they became quiescent [12].
• In the rat cell line, however, no histone H1a was found [13].
• Radiolabeling revealed that species comigrating with the somatic H1 subtypes H1a and H1c were synthesized in maturing oocytes and in one- and two-cell embryos [14].
• To disrupt the compensation, we generated H1t and H1a double null mice by two sequential gene-targeting steps in embryonic stem cells [5].

Associations of Hist1h1a with chemical compounds

• The serine residue was replaced by threonine residue in H1a, and H1b did not have a homologous peptide [7].

Other interactions of Hist1h1a

• Most of the H1 histones, namely H1a, H1c, H1d/e, and H1(0), completely aggregate polynucleosomes (1.3 kilobase pairs, 6 nucleosomes) at 270-360 nM, corresponding to a molar ratio of six to eight H1 molecules per reconstituted nucleosome [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 [11].
• In vivo phosphorylation of the five histone H1 variants H1a-H1e including H1(0) in NIH 3T3 mouse fibroblasts was examined during the cell cycle by using a combination of HPLC techniques and conventional AU gel electrophoresis [16].

Analytical, diagnostic and therapeutic context of Hist1h1a

• These data demonstrate that in situ hybridization with H1.1 mRNA-specific probes can serve to identify germ cells with ongoing DNA replication [17].
• In situ hybridization and immunohistochemistry with testis from 5-, 9-, and 20-day-old mice showed that H1.1 mRNA and protein was already present in spermatogonia of the prepuberal testis [17].
• One of the five hybridomas that gave a positive reaction in an enzyme-linked immunosorbent assay was selected (H1a) for structural analysis and immunolocalization of type IX collagen [18].

References