scholarly journals Epigenetic Regulation of Plant Gametophyte Development

2019 ◽  
Vol 20 (12) ◽  
pp. 3051 ◽  
Author(s):  
Vasily V. Ashapkin ◽  
Lyudmila I. Kutueva ◽  
Nadezhda I. Aleksandrushkina ◽  
Boris F. Vanyushin
Keyword(s):  
Mother Cell ◽  
Female Gametophyte ◽  
Male Gametophyte ◽  
Endosperm Development ◽  
Epigenetic Changes ◽  
Gametophyte Development ◽  
Daughter Cells ◽  
Second Stage ◽  
Somatic Tissues ◽  
Mother Cells

Unlike in animals, the reproductive lineage cells in plants differentiate from within somatic tissues late in development to produce a specific haploid generation of the life cycle—male and female gametophytes. In flowering plants, the male gametophyte develops within the anthers and the female gametophyte—within the ovule. Both gametophytes consist of only a few cells. There are two major stages of gametophyte development—meiotic and post-meiotic. In the first stage, sporocyte mother cells differentiate within the anther (pollen mother cell) and the ovule (megaspore mother cell). These sporocyte mother cells undergo two meiotic divisions to produce four haploid daughter cells—male spores (microspores) and female spores (megaspores). In the second stage, the haploid spore cells undergo few asymmetric haploid mitotic divisions to produce the 3-cell male or 7-cell female gametophyte. Both stages of gametophyte development involve extensive epigenetic reprogramming, including siRNA dependent changes in DNA methylation and chromatin restructuring. This intricate mosaic of epigenetic changes determines, to a great extent, embryo and endosperm development in the future sporophyte generation.

Seed production and gametophyte formation in Agave tequilana and Agave americana

Botany ◽  
2008 ◽  
Vol 86 (11) ◽  
pp. 1343-1353 ◽  
Author(s):  
Rocio E. Escobar-Guzmán ◽  
Flor Zamudio Hernández ◽  
Katia Gil Vega ◽  
June Simpson
Keyword(s):  
Seed Production ◽  
Female Gametophyte ◽  
Male Gametophyte ◽  
Raw Material ◽  
Low Fertility ◽  
Agave Tequilana ◽  
Genetic Incompatibility ◽  
Gametophyte Development ◽  
Agave Americana ◽  
Female Gametophyte Development

Agave tequilana Weber var. azul is the raw material used in the production of tequila. This species has a life cycle of approximately 6–8 years; however, owing to the practice of removing the inflorescence to conserve accumulated sugar reserves, the main form of reproduction is asexual. Little attention has, therefore, been paid to the process of flowering and the factors leading to low levels of germination and seedling viability have not been investigated in detail. The objective of this study was to document gametophyte development, seed production, and germination in A. tequilana under different pollination treatments and in an interspecies cross with Agave americana L. Seed production and germination efficiency was low for both A. tequilana and A. americana under the different pollination treatments, although interspecies crosses did produce some viable seeds. Development of the male gametophyte in both species is of the successive type, producing pollen grains with dicolpate morphology. Female gametophyte development is of the Polygonum monosporic type. The results obtained suggest that genetic incompatibility, inbreeding effects, factors affecting pollen development and germination, or errors in female gametophyte development may contribute to the low fertility observed for A. tequilana and A. americana.

scholarly journals Temporal integration of mitogen history in mother cells controls proliferation of daughter cells

Science ◽  
2020 ◽  
Vol 368 (6496) ◽  
pp. 1261-1265 ◽  
Author(s):  
Mingwei Min ◽  
Yao Rong ◽  
Chengzhe Tian ◽  
Sabrina L. Spencer
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Mother Cell ◽  
Protein Production ◽  
Temporal Integration ◽  
Protein Translation ◽  
Cycle Phase ◽  
Daughter Cells ◽  
Mother Cells ◽  
Multicellular Organisms

Multicellular organisms use mitogens to regulate cell proliferation, but how fluctuating mitogenic signals are converted into proliferation-quiescence decisions is poorly understood. In this work, we combined live-cell imaging with temporally controlled perturbations to determine the time scale and mechanisms underlying this system in human cells. Contrary to the textbook model that cells sense mitogen availability only in the G1 cell cycle phase, we find that mitogenic signaling is temporally integrated throughout the entire mother cell cycle and that even a 1-hour lapse in mitogen signaling can influence cell proliferation more than 12 hours later. Protein translation rates serve as the integrator that proportionally converts mitogen history into corresponding levels of cyclin D in the G2 phase of the mother cell, which controls the proliferation-quiescence decision in daughter cells and thereby couples protein production with cell proliferation.

Anther and Ovule Development in Tasmannia (Winteraceae)

1992 ◽  
Vol 40 (6) ◽  
pp. 877 ◽  
Author(s):  
N Prakash ◽  
AL Lim ◽  
FB Sampson
Keyword(s):  
Mother Cell ◽  
Female Gametophyte ◽  
Cell Plate ◽  
Basic Type ◽  
Ovule Development ◽  
Linear Tetrad ◽  
Polygonum Type ◽  
Secretory Type ◽  
Mother Cells ◽  
Female Gametophyte Development

Three species of Tasmannia R.Br. ex DC., T. glaucifolia, T. insipida and T. stipitata are studied. The anther is tetrasporangiate and its waU development conforms to the Basic type. The tapetum follows the secretory type of development. Cytokinesis in the microspore mother cells is simultaneous but an evanescent cell plate is present at telophase I and anaphase I1 during meiosis. Pollen tetrads are permanent and tetrahedral. The mature pollen is anaulcerate, reticulate and 2-celled. The ovule. is anatropous, bitegmic and crassinucellate. The micropyle in T. stipitata and T. Glaucifolia is formed by the inner integument only whereas in T. insipida it is formed by both the integuments and is zigzag in outline. Meiosis in the single megaspore mother cell produces a linear or T-shaped megaspore tetrad in T. stipitata and T. glaucifolia but only a linear tetrad in T. insipida. Female gametophyte development is of the monosporic Polygonum type. Fertilisation is porogamous; triple fusion and syngamy occur simultaneously.

scholarly journals The fate of notch-1 transcript is linked to cell cycle dynamics by activity of a natural antisense transcript

2021 ◽  
Vol 49 (18) ◽  
pp. 10419-10430
Author(s):  
Filip Vujovic ◽  
Saba Rezaei-Lotfi ◽  
Neil Hunter ◽  
Ramin M Farahani
Keyword(s):  
Cell Cycle ◽  
Mother Cell ◽  
Antisense Transcript ◽  
Cell Lineage ◽  
G1 Phase ◽  
Natural Antisense Transcript ◽  
Notch 1 ◽  
Daughter Cells ◽  
G0 Phase ◽  
Mother Cells

Abstract A core imprint of metazoan life is that perturbations of cell cycle are offset by compensatory changes in successive cellular generations. This trait enhances robustness of multicellular growth and requires transmission of signaling cues within a cell lineage. Notably, the identity and mode of activity of transgenerational signals remain largely unknown. Here we report the discovery of a natural antisense transcript encoded in exon 25 of notch-1 locus (nAS25) by which mother cells control the fate of notch-1 transcript in daughter cells to buffer against perturbations of cell cycle. The antisense transcript is transcribed at G1 phase of cell cycle from a bi-directional E2F1-dependent promoter in the mother cell where the titer of nAS25 is calibrated to the length of G1. Transmission of the antisense transcript from mother to daughter cells stabilizes notch-1 sense transcript in G0 phase of daughter cells by masking it from RNA editing and resultant nonsense-mediated degradation. In consequence, nAS25-mediated amplification of notch-1 signaling reprograms G1 phase in daughter cells to compensate for the altered dynamics of the mother cell. The function of nAS25/notch-1 in integrating G1 phase history of the mother cell into that of daughter cells is compatible with the predicted activity of a molecular oscillator, slower than cyclins, that coordinates cell cycle within cell lineage.

scholarly journals Mother-daughter asymmetry of pH underlies aging and rejuvenation in yeast

eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Kiersten A Henderson ◽  
Adam L Hughes ◽  
Daniel E Gottschling
Keyword(s):  
Plasma Membrane ◽  
Mother Cell ◽  
Daughter Cell ◽  
Asymmetric Distribution ◽  
Replicative Aging ◽  
Cytosolic Ph ◽  
Daughter Cells ◽  
Proton Atpase ◽  
Mother And Daughter ◽  
Mother Cells

Replicative aging in yeast is asymmetric–mother cells age but their daughter cells are rejuvenated. Here we identify an asymmetry in pH between mother and daughter cells that underlies aging and rejuvenation. Cytosolic pH increases in aging mother cells, but is more acidic in daughter cells. This is due to the asymmetric distribution of the major regulator of cytosolic pH, the plasma membrane proton ATPase (Pma1). Pma1 accumulates in aging mother cells, but is largely absent from nascent daughter cells. We previously found that acidity of the vacuole declines in aging mother cells and limits lifespan, but that daughter cell vacuoles re-acidify. We find that Pma1 activity antagonizes mother cell vacuole acidity by reducing cytosolic protons. However, the inherent asymmetry of Pma1 increases cytosolic proton availability in daughter cells and facilitates vacuole re-acidification and rejuvenation.

scholarly journals A mechanism to prevent transformation of the Whi3 mnemon into a prion

2020 ◽  
Author(s):  
Yasmin Lau ◽  
Iuliia Parfenova ◽  
Juha Saarikangas ◽  
Richard A. Nichols ◽  
Yves Barral ◽  
...  
Keyword(s):  
Mother Cell ◽  
Temporal Stability ◽  
Structural Features ◽  
Yeast Cells ◽  
Membrane Diffusion ◽  
Cell Cycles ◽  
Daughter Cells ◽  
Cycle Arrest ◽  
Mother Cells

AbstractIn response to deceptive courtship, budding yeast cells escape pheromone induced cell cycle arrest through coalescence of the G1/S inhibitor Whi3 into a dominant inactive super-assembly. Strikingly, Whi3 super-assemblies remain stable over many cell cycles in the mother cells and are not passed on to the daughter cells. Thereby, Whi3 coalescence encodes memory, conferring to it the property of a mnemon (Whi3mnem), a protein which conformational change maintain a trait that is permanent in the mother cell but is not inherited by daughter cells. Mnemons share structural features with prions, which are self-templating protein conformations that are inherited by daughter cells. Yet, how the maintenance and asymmetric inheritance of Whi3mnem are achieved is unknown. Here, we report that Whi3mnem is closely associated with endoplasmic reticulum (ER) membranes and retained in the mother cell by the presence of lateral membrane diffusion barriers at the bud neck. Strikingly, barrier defects made Whi3mnem propagate in a mitotically stable manner, like a prion. Alike Whi3mnem, transformation of Whi3 into a prion required its poly-glutamine prion-like domain. Thus, we propose that Whi3mnem is in a self-templating state, lending temporal stability to the memory that it encodes, while its anchorage into the compartmentalized membranes of the ER ensures its confinement in the mother cell and prevents its infectious propagation. These results suggest that confined self-templating super-assembly is a powerful mechanism for the long-term encoding of information.

scholarly journals Pollination triggers female gametophyte development in immature Nicotiana tabacum flowers

2015 ◽  
Vol 6 ◽  
Author(s):  
Michael S. Brito ◽  
Lígia T. Bertolino ◽  
Viviane Cossalter ◽  
Andréa C. Quiapim ◽  
Henrique C. DePaoli ◽  
...  
Keyword(s):  
Nicotiana Tabacum ◽  
Female Gametophyte ◽  
Gametophyte Development ◽  
Female Gametophyte Development
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