SOL1 and SOL2 Regulate Fate Transition and Cell Divisions in the Arabidopsis Stomatal Lineage

AbstractIn the stomatal lineage, cells make fate transitions from asymmetrically dividing and self-renewing meristemoids, to commitment to the guard mother cell identity, and finally though a single division to create mature, post-mitotic stomatal guard cells. Flexibility in the stomatal lineage allows plants to alter leaf size and stomatal density in response to environmental conditions; however, transitions must be clean and unidirectional in order to produce functional and correctly patterned stomata. Among direct transcriptional targets of the stomatal initiating factor, SPEECHLESS, we found a pair of genes, SOL1 and SOL2, required for effective transitions in the lineage. Here we show that these two genes, which are homologues of the LIN54 DNA-binding components of the mammalian DREAM complex, are expressed in a cell cycle dependent manner and regulate cell fate and division properties in the self-renewing early lineage. In the terminal division of the stomatal lineage, however, these two proteins appear to act in opposition to their closest paralogue, TSO1, revealing complexity in the gene family may enable customization of cell divisions in coordination with development.

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Regardless of the deposition pathway, aminoacid 31 in histone variant H3 is essential at gastrulation in Xenopus

10.1101/612515 ◽

2019 ◽

Author(s):

David Sitbon ◽

Ekaterina Boyarchuk ◽

Geneviève Almouzni

Keyword(s):

Cell Cycle ◽

Cell Fate ◽

Unique Property ◽

Dependent Manner ◽

Critical Importance ◽

Distinct Mode ◽

Developmental Defects ◽

A Cell ◽

Cycle Dependent ◽

Conserved Residue

AbstractThe closely related replicative H3 and non-replicative H3.3 variants show specific requirement during development in vertebrates. Whether it involves distinct mode of deposition or unique roles once incorporated into chromatin remains unclear. To disentangle the two aspects, we took advantage of the Xenopus early development combined with chromatin assays. Our previous work showed that in Xenopus, depletion of the non-replicative variant H3.3 impairs development at gastrulation, without compensation through provision of the replicative variant H3.2. We systematically mutated H3.3 at each four residues that differ from H3.2 and tested their ability to rescue developmental defects. Surprisingly, all H3.3 mutated variants functionally complemented endogenous H3.3, regardless of their incorporation pathways, except for one residue. This particular residue, the serine at position 31 in H3.3, gets phosphorylated onto chromatin in a cell cycle dependent manner. While the alanine substitution failed to rescue H3.3 depletion, a phosphomimic residue sufficed. We conclude that the time of gastrulation reveals a critical importance of the H3.3S31 residue independently of the variant incorporation pathway. We discuss how this single evolutionary conserved residue conveys a unique property for this variant in vertebrates during cell cycle and cell fate commitment.

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Truncated APC regulates the transcriptional activity of β-catenin in a cell cycle dependent manner

Human Molecular Genetics ◽

10.1093/hmg/ddl464 ◽

2006 ◽

Vol 16 (2) ◽

pp. 199-209 ◽

Cited By ~ 38

Author(s):

Jean Schneikert ◽

Annette Grohmann ◽

Jürgen Behrens

Keyword(s):

Cell Cycle ◽

Transcriptional Activity ◽

Dependent Manner ◽

A Cell ◽

Cycle Dependent

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Structural models for the self-assembly and microtubule interactions of gamma-, delta- and epsilon-tubulin

Journal of Cell Science ◽

10.1242/jcs.114.2.413 ◽

2001 ◽

Vol 114 (2) ◽

pp. 413-422 ◽

Cited By ~ 2

Author(s):

Y.F. Inclan ◽

E. Nogales

Keyword(s):

Self Assembly ◽

Structural Models ◽

Dependent Manner ◽

Gamma Delta ◽

Sequence Comparisons ◽

Alpha Tubulin ◽

A Cell ◽

Gamma Tubulin ◽

Cycle Dependent ◽

Key Residues

alphabeta-tubulin heterodimers self-assemble to form microtubules nucleated by gamma-tubulin in the cell. Gamma-tubulin is believed to recruit the alphabeta-tubulin dimers that form the minus ends of microtubules, but the molecular mechanism of this action remains a matter of heated controversy. Still less is known about the function and molecular interactions of delta-tubulin and epsilon-tubulin. delta-tubulin may seed the formation of the C triplet tubules in the basal bodies of Chlamydomonas and epsilon-tubulin is known to localize to the centrosome in a cell cycle-dependent manner. Using the structure of alphabeta tubulin as a model, we have analyzed the sequences of gamma-, delta- and epsilon-tubulin in regions corresponding to different polymerization interfaces in the tubulin alphabeta dimer. The sequence comparisons sometimes show clear conservation, pointing to similar types of contacts being functionally important for the new tubulin considered. Conversely, certain surfaces show marked differences that rule out equivalent interactions for non-microtubular tubulins. This sequence/structure analysis has led us to structural models of how these special tubulins may be involved in protein-protein contacts that affect microtubule self-assembly. delta-tubulin most likely interacts longitudinally with alpha-tubulin at the minus ends of microtubules, while epsilon-tubulin most likely binds to the plus end of beta-tubulin. Conservation of key residues in gamma-tubulin suggests that it is capable of longitudinal self-assembly. The implications for the protofilament and template models of nucleation are considered.

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p53 Plays a Role in Mesenchymal Differentiation Programs, in a Cell Fate Dependent Manner

PLoS ONE ◽

10.1371/journal.pone.0003707 ◽

2008 ◽

Vol 3 (11) ◽

pp. e3707 ◽

Cited By ~ 112

Author(s):

Alina Molchadsky ◽

Igor Shats ◽

Naomi Goldfinger ◽

Meirav Pevsner-Fischer ◽

Melissa Olson ◽

...

Keyword(s):

Cell Fate ◽

Dependent Manner ◽

Mesenchymal Differentiation ◽

A Cell

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Ser68 phosphoregulation is essential for CENP-A deposition, centromere function and viability in mice

10.1101/2021.11.23.469796 ◽

2021 ◽

Author(s):

Yuting Liu ◽

Kehui Wang ◽

Li Huang ◽

Jicheng Zhao ◽

Xinpeng Chen ◽

...

Keyword(s):

Cell Cycle ◽

Cell Viability ◽

Histone H3 ◽

Dependent Manner ◽

Centromere Function ◽

Histone H3 Variant ◽

A Cell ◽

Cycle Dependent ◽

Spatiotemporal Control

Centromere identity is defined by nucleosomes containing CENP-A, a histone H3 variant. The deposition of CENP-A at centromeres is tightly regulated in a cell-cycle-dependent manner. We previously reported that the spatiotemporal control of centromeric CENP-A incorporation is mediated by the phosphorylation of CENP-A Ser68. However, a recent report argued that Ser68 phosphoregulation is dispensable for accurate CENP-A loading. Here, we report that the substitution of Ser68 of endogenous CENP-A with either Gln68 or Glu68 severely impairs CENP-A deposition and cell viability. We also find that mice harboring the corresponding mutations are lethal. Together, these results indicate that the dynamic phosphorylation of Ser68 ensures cell-cycle-dependent CENP-A deposition and cell viability.

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Gcn5-mediated acetylation at MBF-regulated promoters induces the G1/S transcriptional wave

Nucleic Acids Research ◽

10.1093/nar/gkz561 ◽

2019 ◽

Vol 47 (16) ◽

pp. 8439-8451 ◽

Cited By ~ 1

Author(s):

Alberto González-Medina ◽

Elena Hidalgo ◽

José Ayté

Keyword(s):

Cell Cycle ◽

Molecular Mechanisms ◽

Histone H3 ◽

Dependent Manner ◽

Saga Complex ◽

Lysine Residues ◽

Physical Barriers ◽

A Cell ◽

Cycle Dependent ◽

Regulated Promoters

Abstract In fission yeast, MBF-dependent transcription is inactivated at the end of S phase through a negative feedback loop that involves the co-repressors, Yox1 and Nrm1. Although this repression system is well known, the molecular mechanisms involved in MBF activation remain largely unknown. Compacted chromatin constitutes a barrier to activators accessing promoters. Here, we show that chromatin regulation plays a key role in activating MBF-dependent transcription. Gcn5, a part of the SAGA complex, binds to MBF-regulated promoters through the MBF co-activator Rep2 in a cell cycle-dependent manner and in a reverse correlation to the binding of the MBF co-repressors, Nrm1 or Yox1. We propose that the co-repressors function as physical barriers to SAGA recruitment onto MBF promoters. We also show that Gcn5 acetylates specific lysine residues on histone H3 in a cell cycle-regulated manner. Furthermore, either in a gcn5 mutant or in a strain in which histone H3 is kept in an unacetylated form, MBF-dependent transcription is downregulated. In summary, Gcn5 is required for the full activation and correct timing of MBF-regulated gene transcription.

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The Epigenetic Repertoire of Daphnia magna Includes Modified Histones

Genetics Research International ◽

10.1155/2012/174860 ◽

2012 ◽

Vol 2012 ◽

pp. 1-7 ◽

Cited By ~ 9

Author(s):

Nicole F. Robichaud ◽

Jeanette Sassine ◽

Margaret J. Beaton ◽

Vett K. Lloyd

Keyword(s):

Life Cycle ◽

Histone H3 ◽

Dependent Manner ◽

Nurse Cells ◽

Important Species ◽

Clonal Population ◽

A Cell ◽

Cycle Dependent

Daphnids are fresh water microcrustaceans, many of which follow a cyclically parthenogenetic life cycle. Daphnia species have been well studied in the context of ecology, toxicology, and evolution, but their epigenetics remain largely unexamined even though sex determination, the production of sexual females and males, and distinct adult morphological phenotypes, are determined epigenetically. Here, we report on the characterization of histone modifications in Daphnia. We show that a number of histone H3 and H4 modifications are present in Daphnia embryos and histone H3 dimethylated at lysine 4 (H3K4me2) is present nonuniformly in the nucleus in a cell cycle-dependent manner. In addition, this histone modification, while present in blastula and gastrula cells as well as the somatic cells of adults, is absent or reduced in oocytes and nurse cells. Thus, the epigenetic repertoire of Daphnia includes modified histones and as these epigenetic forces act on a genetically homogeneous clonal population Daphnia offers an exceptional tool to investigate the mechanism and role of epigenetics in the life cycle and development of an ecologically important species.

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