A single copy of linker H1 genes is enough for proliferation of the DT40 chicken B cell line, and linker H1 variants participate in regulation of gene expression

Yasuda, Takami; Nakayama, Tatsuo

doi:10.1046/j.1365-2443.1997.1550353.x

Cited by 38 publications

(31 citation statements)

References 46 publications

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“…This observation suggests that histone H1 specifically modulates cfp expression in N. crassa and that cfp expression is not position dependent. Our suggestion that histone H1 participates in the expression of specific genes in Neurospora is consistent with previous studies showing that the depletion of H1 resulted in the induction of some genes but in the repression of others (58,60,67). Linker histones traditionally have been considered "stabilizers" of higher-order chromatin structure by rendering a condensed chromatin state, but it is also conceivable that histone H1 destabilizes chromatin and thus facilitates interactions of DNA with transcription factors.…”

Section: Discussionsupporting

confidence: 92%

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Histone H1 Is Required for Proper Regulation of Pyruvate Decarboxylase Gene Expression in Neurospora crassa

et al. 2003

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We show that Neurospora crassa has a single histone H1 gene, hH1, which encodes a typical linker histone with highly basic N-and C-terminal tails and a central globular domain. A green fluorescent protein-tagged histone H1 chimeric protein was localized exclusively to nuclei. Mutation of hH1 by repeat-induced point mutation (RIP) did not result in detectable defects in morphology, DNA methylation, mutagen sensitivity, DNA repair, fertility, RIP, chromosome pairing, or chromosome segregation. Nevertheless, hH1 mutants had mycelial elongation rates that were lower than normal on all tested carbon sources. This slow linear growth phenotype, however, was less evident on medium containing ethanol. The pyruvate decarboxylase gene, cfp, was abnormally derepressed in hH1 mutants on ethanol-containing medium. This derepression was also found when an ectopically integrated fusion of the cfp gene promoter to the reporter gene hph was analyzed. Thus, Neurospora histone H1 is required for the proper regulation of cfp, a gene with a key role in the respiratoryfermentative pathway.

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Section: Discussionsupporting

confidence: 92%

“…Additional clues to the possible functions of H1 have come from in vivo studies. In higher eukaryotes, which have multiple linker histone genes subject to developmental regulation (30), some H1 variants seem to be dispensable (13,60). In tobacco, H1 plays roles in development and male meiosis (49).…”

mentioning

confidence: 99%

Histone H1 Is Required for Proper Regulation of Pyruvate Decarboxylase Gene Expression in Neurospora crassa

et al. 2003

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“…DT40 cells and their mutants were cultured as described previously (Takami and Nakayama, 1997). To determine growth rate, the cells were counted at indicated times.…”

Section: Cell Culture and Transfectionmentioning

confidence: 99%

“…To determine growth rate, the cells were counted at indicated times. Transfections and selections of drug-resistant cells were conducted as described previously (Takami and Nakayama, 1997).…”

Section: Cell Culture and Transfectionmentioning

confidence: 99%

Essential Role of Chromatin Assembly Factor-1–mediated Rapid Nucleosome Assembly for DNA Replication and Cell Division in Vertebrate Cells

Yasuda

Ono²,

Fukagawa

et al. 2007

MBoC

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Chromatin assembly factor-1 (CAF-1), a complex consisting of p150, p60, and p48 subunits, is highly conserved from yeast to humans and facilitates nucleosome assembly of newly replicated DNA in vitro. To investigate roles of CAF-1 in vertebrates, we generated two conditional DT40 mutants, respectively, devoid of CAF-1p150 and p60. Depletion of each of these CAF-1 subunits led to delayed S-phase progression concomitant with slow DNA synthesis, followed by accumulation in late S/G 2 phase and aberrant mitosis associated with extra centrosomes, and then the final consequence was cell death. We demonstrated that CAF-1 is necessary for rapid nucleosome formation during DNA replication in vivo as well as in vitro. Loss of CAF-1 was not associated with the apparent induction of phosphorylations of S-checkpoint kinases Chk1 and Chk2. To elucidate the precise role of domain(s) in CAF-1p150, functional dissection analyses including rescue assays were preformed. Results showed that the binding abilities of CAF-1p150 with CAF-1p60 and DNA polymerase sliding clamp proliferating cell nuclear antigen (PCNA) but not with heterochromatin protein HP1-␥ are required for cell viability. These observations highlighted the essential role of CAF-1-dependent nucleosome assembly in DNA replication and cell proliferation through its interaction with PCNA.

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“…In yeast, H1 is responsible for the repression of only a few genes, while the expression of a sizable subset of genes actually decreases in its absence (32). In chicken tissue culture cells, deletion of all but one of the H1 genes caused changes in the pattern of proteins analyzed on two-dimensional gels without altering cell growth (61). Similar gene-specific effects of H1 depletion were also established during Xenopus laevis early embryonic development (59), and specific roles of some linker histone variants in germ line development have also been reported in Caenorhabditis elegans (35) and in tobacco (50).…”

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confidence: 99%

The H1 Phosphorylation State Regulates Expression of CDC2 and Other Genes in Response to Starvation in Tetrahymena thermophila

Dou

Song

Liu

et al. 2005

Molecular and Cellular Biology

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In Tetrahymena thermophila, highly phosphorylated histone H1 of growing cells becomes partially dephosphorylated when cells are starved in preparation for conjugation. To determine the effects of H1 phosphorylation on gene expression, PCR-based subtractive hybridization was used to clone cDNAs that were differentially expressed during starvation in two otherwise-isogenic strains differing only in their H1s. H1 in A5 mutant cells lacked phosphorylation, and H1 in E5 cells mimicked constitutive H1 phosphorylation. Sequences enriched in A5 cells included genes encoding proteases. Sequences enriched in E5 cells included genes encoding cdc2 kinase and a Ser/Thr kinase. These results indicate that H1 phosphorylation plays an important role in regulating the pattern of gene expression during the starvation response and that its role in transcription regulation can be either positive or negative. Treatment of starved cells with a phosphatase inhibitor caused CDC2 gene overexpression. Expression of the E5 version of H1 in starved cells containing endogenous, wild-type H1 caused the wild-type H1 to remain highly phosphorylated. These results argue that Cdc2p is the kinase that phosphorylates Tetrahymena H1, establish a positive feedback mechanism between H1 phosphorylation and CDC2 expression, and indicate that CDC2 gene expression is regulated by an H1 phosphatase.The organization of nuclear DNA into nucleosomes by histones and the folding of nucleosomes into higher-order chromatin structures are generally believed to compact DNA and make it inaccessible to factors required for transcription (see references 30 and 34). There is now compelling evidence that chromatin structural modifications are actively involved in transcription regulation, and extensive physical and functional interactions among transcription factors, chromatin modifying activities, and nucleosomes are well documented (67). Linker histones (H1 and related proteins) have been strongly implicated in modulating chromatin structure and function at multiple levels (66). They are key components of the nucleosome, the most basic level of the hierarchy of chromatin structure in eukaryotes, where they provide extra protection to DNA wrapped around the core histone octamer, presumably by interacting with the DNA strand where it enters and exits the nucleosome core. Linker histones can affect nucleosome mobility (49) and spacing (6). They also stabilize the folding of nucleosome arrays and the association of folded arrays in vitro (10), probably by interacting with the core histone tails (11). However, in spite of intensive study, there is little agreement regarding the precise location of linker histones in nucleosomes (64) and little insight into the mechanisms by which they influence higher orders of chromatin structure.Linker histones have been implicated in the regulation of transcription and were long thought to serve as global repressors (70). However, a number of studies in a variety of organisms have found that linker histones have highly specific effects...

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A single copy of linker H1 genes is enough for proliferation of the DT40 chicken B cell line, and linker H1 variants participate in regulation of gene expression

Cited by 38 publications

References 46 publications

Histone H1 Is Required for Proper Regulation of Pyruvate Decarboxylase Gene Expression in Neurospora crassa

Histone H1 Is Required for Proper Regulation of Pyruvate Decarboxylase Gene Expression in Neurospora crassa

Essential Role of Chromatin Assembly Factor-1–mediated Rapid Nucleosome Assembly for DNA Replication and Cell Division in Vertebrate Cells

The H1 Phosphorylation State Regulates Expression of CDC2 and Other Genes in Response to Starvation in Tetrahymena thermophila

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