scholarly journals TSO1 functions in cell division during Arabidopsis flower development

Development ◽  
1997 ◽  
Vol 124 (3) ◽  
pp. 665-672 ◽  
Author(s):  
Z. Liu ◽  
M.P. Running ◽  
E.M. Meyerowitz
Keyword(s):  
Cell Division ◽  
Flower Development ◽  
Cell Walls ◽  
Dna Ploidy ◽  
Floral Meristem ◽  
Specific Cell ◽  
Floral Organs ◽  
Size And Shape ◽  
Cell Layers ◽  
Arabidopsis Mutant

We describe an Arabidopsis mutant, tso1, which develops callus-like tissues in place of floral organs. The tso1 floral meristem lacks properly organized three cell layers, and the nuclei of these cells are irregular in size and shape. Further analyses reveal partially formed cell walls and increased DNA ploidy in tso1 floral meristem cells, indicating defects in mitosis and cytokinesis. Our finding that TSO1 is required for organ formation in floral tissues but not in other tissues indicates that TSO1 may encode a floral-specific cell division component, or that TSO1 function is redundant in nonfloral tissues.

scholarly journals Quantitative live-imaging of Aquilegia floral meristems reveals distinct patterns of floral organ initiation and cell-level dynamics of floral meristem termination

2021 ◽  
Author(s):  
Ya Min ◽  
Stephanie J. Conway ◽  
Elena M. Kramer
Keyword(s):  
Cell Division ◽  
Floral Organ ◽  
Live Imaging ◽  
Confocal Imaging ◽  
Floral Meristem ◽  
Flowering Plant ◽  
Molecular Networks ◽  
Floral Organs ◽  
Meristem Development ◽  
Floral Meristems

ABSTRACTIn-depth investigation of any developmental process in plants requires knowledge of both the underpinning molecular networks and how they directly determine patterns of cell division and expansion over time. Floral meristems (FM) produce floral organs, after which they undergo floral meristem termination (FMT), and precise control of organ initiation and FMT is crucial to reproductive success of any flowering plant. Using a live confocal imaging, we characterized developmental dynamics during floral organ primordia initiation and FMT in Aquilegia coerulea (Ranunculaceae). Our results have uncovered distinct patterns of primordium initiation between stamens and staminodes compared to carpels, and provided insight into the process of FMT, which is discernable based on cell division dynamics preceding carpel initiation. To our knowledge, this is the first quantitative live imaging of meristem development in a system with numerous whorls of floral organs as well as an apocarpous gynoecium. This study provides crucial information for our understanding of how the spatial-temporal regulation of floral meristem behavior is achieved in both an evolutionary and developmental context.

scholarly journals Cell Division and Expansion in Petals during Flower Development and Opening in Eustoma grandiflorum

2016 ◽  
Vol 85 (2) ◽  
pp. 154-160 ◽  
Author(s):  
Ryo Norikoshi ◽  
Takehiko Shibata ◽  
Kazuo Ichimura
Keyword(s):  
Cell Division ◽  
Flower Development ◽  
Eustoma Grandiflorum

Ontogenetical and experimental studies of the floral apex of Portulaca grandiflora. 1. Histology of transformation of the shoot apex into the floral apex

1969 ◽  
Vol 47 (1) ◽  
pp. 133-140 ◽  
Author(s):  
Siti Raswati Soetiarto ◽  
Ernest Ball
Keyword(s):  
Shoot Apex ◽  
Experimental Studies ◽  
Floral Meristem ◽  
Vegetative Shoot ◽  
Floral Organs ◽  
Mature Flower ◽  
Floral Apex ◽  
Portulaca Grandiflora ◽  
Floral Primordia ◽  
Vegetative Shoot Apex

The vegetative apex was a low dome consisting of two layers of tunica surmounting a very small corpus. Foliar primordia originated as periclines in the flanks of T2. The transition apex became first a steep cone and then a hemisphere. All floral primordia—the two bracts, the two sepals, the several whorls of petals, the several whorls of stamens, and the carpels—originated in the manner of leaves, as periclines in T2 on the flanks of the apex. All appendages, including carpels, were therefore lateral. In the early transition, the apex had a brief stage in which there were three tunica layers, but the inner one was lost with the onset of the sepals. The bracts and the first sepal continued the normal positions of primordia for the vegetative phyllotaxy of 3/8, but with the second sepal, this phyllotaxy was lost, and petals, stamens, and carpels were produced in whorls. While leaves, bracts, sepals, and petals were produced in acropetal sequence, stamens were produced in basipetal sequence, and carpels appeared simultaneously. After carpels were formed, the rest of the floral apex underwent a brief period of expansion growth, achieving a diameter comparable to that of a shoot apex, but its substance was eventually incorporated into the carpel margins, which later produced the ovules. This agrees with the determinate nature of the floral apex. During the development of the first series of floral organs, the floral apex underwent continued increase in area, finally achieving a diameter several times that of the vegetative shoot apex. Its size and form were such that they were compared to those of some inflorescence apices. After development of the first series of floral organs, the subjacent tissues to the floral meristem underwent divisions and elongation at right angles to the axis, causing at first a flattening of the meristem, and eventually a cup-shaped form, with the carpels attached in the bottom of a bowl. The mature flower was thus perigynous, but this development arose quite differently from the perigyny as it is known from ontogenetic studies in the Rosaceae.

scholarly journals Generation of asymmetry during development. Segregation of type-specific proteins in Caulobacter.

1979 ◽  
Vol 81 (1) ◽  
pp. 123-136 ◽  
Author(s):  
N Agabian ◽  
M Evinger ◽  
G Parker
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Messenger Rna ◽  
Cell Types ◽  
Specific Protein ◽  
Soluble Proteins ◽  
Specific Cell ◽  
Daughter Cells ◽  
Specific Proteins ◽  
Entire Cell

An essential event in developmental processes is the introduction of asymmetry into an otherwise undifferentiated cell population. Cell division in Caulobacter is asymmetric; the progeny cells are structurally different and follow different sequences of development, thus providing a useful model system for the study of differentiation. Because the progeny cells are different from one another, there must be a segregation of morphogenetic and informational components at some time in the cell cycle. We have examined the pattern of specific protein segregation between Caulobacter stalked and swarmer daughter cells, with the rationale that such a progeny analysis would identify both structurally and developmentally important proteins. To complement the study, we have also examined the pattern of protein synthesis during synchronous growth and in various cellular fractions. We show here, for the first time, that the association of proteins with a specific cell type may result not only from their periodicity of synthesis, but also from their pattern of distribution at the time of cell division. Several membrane-associated and soluble proteins are segregated asymmetrically between progeny stalked and swarmer cells. The data further show that a subclass of soluble proteins becomes associated with the membrane of the progeny stalked cells. Therefore, although the principal differentiated cell types possess different synthetic capabilities and characteristic proteins, the asymmetry between progeny stalked and swarmer cells is generated primarily by the preferential association of specific soluble proteins with the membrane of only one daughter cell. The majority of the proteins which exhibit this segregation behavior are synthesized during the entire cell cycle and exhibit relatively long, functional messenger RNA half-lives.

scholarly journals Next-Generation Multimodality of Nanomedicine Therapy: Size and Structure Dependence of Folic Acid Conjugated Copolymers Actively Target Cancer Cells in Disabling Cell Division and Inducing Apoptosis

Cancers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1698 ◽  
Author(s):  
Sambi ◽  
DeCarlo ◽  
Malardier-Jugroot ◽  
Szewczuk
Keyword(s):  
Folic Acid ◽  
Cell Division ◽  
Cancer Cells ◽  
Multimodality Treatment ◽  
Structural Shape ◽  
Cellular Targets ◽  
Size And Shape ◽  
Large Size ◽  
Copolymer Poly ◽  
Secondary Mechanism

Nanomedicine as a multimodality treatment of cancer utilizes the advantages of nanodelivery systems of drugs. They are superior to the clinical administration of different therapeutic agents in several aspects, including simultaneous delivery of drugs to the active site, precise ratio control of the loading drugs and overcoming multidrug resistance. The role of nanopolymer size and structural shape on the internalization process and subsequent intracellular toxicity is limited. Here, the size and shape dependent mechanism of a functionalized copolymer was investigated using folic acid (FA) covalently bonded to the copolymer poly (styrene-alt-maleic anhydride) (SMA) on its hydrophilic exterior via a biological linker 2,4-diaminobutyric acid (DABA) to target folic acid receptors (FR) overly expressed on cancer cells actively. We recently reported that unloaded FA-DABA-SMA copolymers significantly reduced cancer cell viability, suggesting a secondary therapeutic mechanism of action of the copolymer carrier post-internalization. Here, we investigated the size and shape dependent secondary mechanism of unloaded 350 kDa and 20 kDa FA-DABA-SMA. The 350 kDa and 20 kDa copolymers actively target folic acid receptors (FR) to initialize internationalization, but only the large size and sheet shaped copolymer disables cell division by intracellular disruptions of essential oncogenic proteins including p53, STAT-3 and c-Myc. Furthermore, the 350 kDa FA-DABA-SMA activates early and late apoptotic events in both PANC-1 and MDA-MB-231 cancer cells. These findings indicate that the large size and structural sheet shape of the 350 kDa FA-DABA-SMA copolymer facilitate multimodal tumor targeting mechanisms together with the ability to internalize hydrophobic chemotherapeutics to disable critical oncogenic proteins controlling cell division and to induce apoptosis. The significance of these novel findings reveals copolymer secondary cellular targets and therapeutic actions that extend beyond the direct delivery of chemotherapeutics. This report offers novel therapeutic insight into the intracellular activity of copolymers critically dependent on the size and structural shape of the nanopolymers.

scholarly journals The UNUSUAL FLORAL ORGANS gene of Arabidopsis thaliana is an F-box protein required for normal patterning and growth in the floral meristem

1999 ◽  
Vol 20 (4) ◽  
pp. 433-445 ◽  
Author(s):  
Alon Samach ◽  
Jennifer E. Klenz ◽  
Susanne E. Kohalmi ◽  
Eddy Risseeuw ◽  
George W. Haughn ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Floral Meristem ◽  
Floral Organs ◽  
F Box Protein

The growth of apricot fruit. II. The effects of temperature and gibberellic acid

1967 ◽  
Vol 18 (1) ◽  
pp. 95 ◽  
Author(s):  
DI Jackson ◽  
BG Coombe
Keyword(s):  
Growth Rate ◽  
Cell Division ◽  
Gibberellic Acid ◽  
Fruit Size ◽  
Fruit Growth ◽  
Cell Diameter ◽  
Initial Growth ◽  
Endogenous Gibberellin ◽  
Flower Buds ◽  
Size And Shape

The effect of temperature and gibberellic acid (GA3) applications on apricot fruit have been determined by measurements of fruit size and shape, mesocarp cell number, size, and shape, and endogenous gibberellin. Application of heat during the first 10 nights after anthesis increased the initial growth rate of fruit and of cells in the mesocarp and produced more rapid cell division in this tissue. It did not affect final fruit size or the number and diameter of cells in the mesocarp. Higher temperatures did, however, hasten maturity of fruit. GA3 perfused into branches before anthesis produced an increased drop of flower buds and fruit, raised the ratio of flower buds to leaf buds initiated that season, and resulted in elongated pedicels. Initially, fruit growth rate was increased by GA3, but subsequently it was depressed and final size was below normal. These effects on fruit size were mainly due to effects on the rate of cell division. Some differences were noted in the dimensions of cells but final radial cell diameter did not differ from untreated fruit. GA3-treated fruit ripened sooner than controls. Neither heating nor GA3 treatments affected the level of endogenous gibberellin-like substances in the fruit or their RF on paper chromatograms. There were no significant interactions between temperature and gibberellin in any parameter of apricot fruit growth.

scholarly journals Comparative anatomy of the absorption roots of terrestrial and epiphytic orchids

2008 ◽  
Vol 51 (1) ◽  
pp. 83-93 ◽  
Author(s):  
Ana Sílvia Franco Pinheiro Moreira ◽  
Rosy Mary dos Santos Isaias
Keyword(s):  
Cell Walls ◽  
Comparative Anatomy ◽  
Evolutionary Process ◽  
Minas Gerais ◽  
Point Of View ◽  
Endodermal Cell ◽  
Epiphytic Orchids ◽  
Anatomical Characteristics ◽  
Cell Layers ◽  
Casparian Strips

The present study compared roots of terrestrial and epiphytic Orchidaceae, analyzing the anatomical characteristics from an ecological point of view. The material was collected at three different sites in Minas Gerais / Brazil and was fixed in FAA. Transverse sections were obtained by freehand sections or from material previously embedded in Paraplast® or Historesin®. The prominent characteristics of the epiphytic group were: significant smaller perimeter, epidermis with 3 or more cell layers, U-thickened exodermal cell walls, O-thickened endodermal cell walls, and a low ratio between the caliber and the number of protoxylem arches. The terrestrial group presented simple or multiseriate epidermis, and exodermis and endodermis with typical Casparian strips. The anatomical characteristics should have evolved with several adaptations to distinct environments during evolutionary process.

Hematopoietic Transcriptional Regulation At The Mitosis-G1 Transition

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 2440-2440
Author(s):  
Chris C.S. Hsiung ◽  
Arjun Raj ◽  
Gerd A. Blobel
Keyword(s):  
Gene Expression ◽  
Cell Cycle ◽  
Gene Regulation ◽  
Cell Division ◽  
Rna Polymerase Ii ◽  
Single Molecule ◽  
Conflicts Of Interest ◽  
Specific Cell ◽  
Developmental Gene ◽  
Developmental Gene Regulation

Abstract Normal hematopoiesis involves the coordination of cell division and gene expression to produce physiologically appropriate cell numbers of various developmental stages across lineages. While studies have demonstrated intricate links between cell cycle progression and developmental gene regulation -- two cellular programs whose concomitant dysregulation is central to many malignant and non-malignant hematologic diseases -- researchers currently lack clear, general principles of how intrinsic properties of cell division could influence developmental gene regulation. In each round of division, mitosis imposes a striking disruption to gene expression: the nucleus is disassembled, bulk RNA synthesis ceases, and the transcription machinery and most transcription factors -- including repressive complexes -- are evicted from mitotic chromatin. Since hematopoietic lineage fidelity often requires the continued presence of repressive complexes to inhibit expression of developmentally inappropriate genes, we hypothesized that such repression may be inefficient during a narrow window immediately post-mitosis, resulting in transient aberrant transcription in a probabilistic manner. We tested for the presence of transient post-mitotic aberrant transcription at genes whose repression is known to depend on continued occupancy of repressive complexes. We used an experimentally tractable cell line, G1E cells, a rapidly dividing model of lineage-committed murine pro-erythroblasts that genetically lack the erythroid master regulator Gata1. Transduction with a Gata1-estrogen receptor fusion construct and treatment with estradiol restores Gata1 function, leading to recapitulation of early erythroid maturation events, including rapid repression of stemness-associated genes, such as Gata2 and c-Kit. We examined in fine temporal detail the post-mitotic transcriptional behavior of Gata2, c-Kit and other genes using population-based assays facilitated by drug-mediated cell cycle synchronization. In addition, we bypassed the use of synchronization drugs and their associated potential experimental artifacts by developing novel complementary methods to study the relationship between cell cycle status and transcription in asynchronous populations: 1. We harnessed single-molecule RNA fluorescence in situ hybridization technology to quantitatively assess transcription in individual cells at various cell cycle stages, and 2. We adapted a fluorescent protein cell cycle reporter to separate, using fluorescence-activated cell sorting, subpopulations of specific cell cycle stages for epigenomic and transcriptomic analyses. Together, our results revealed a post-mitotic pulse of increased RNA polymerase II recruitment and transcript synthesis most clearly exhibited by Gata2, c-Kit, and other genes whose repression is known to depend on co-repressor complexes in these cells. Our results support the notion that the mitosis-G1 transition presents a window of transcriptional plasticity. We are beginning to explore how this property of post-mitotic transcriptional control applies to hematopoietic cell types across the developmental spectrum and could contribute to functionally important variations in gene expression, such as in stem cell lineage commitment, experimental reprogramming, and non-genetic heterogeneity in malignancy. Disclosures: No relevant conflicts of interest to declare.

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