scholarly journals A new role for Notch in the control of polarity and asymmetric cell division of developing T cells

2019 ◽  
Author(s):  
Mirren Charnley ◽  
Mandy Ludford-Menting ◽  
Kim Pham ◽  
Sarah M. Russell
Keyword(s):  
T Cells ◽  
Cell Division ◽  
Cell Fate ◽  
Asymmetric Cell Division ◽  
Single Cells ◽  
Cell Types ◽  
Notch Signalling ◽  
Pass Through ◽  
Fate Determinants ◽  
Different Cell Types

AbstractA fundamental question in biology is how single cells can reliably produce progeny of different cell types. Notch signalling frequently facilitates fate determination. Asymmetric cell division (ACD) often controls segregation of Notch signalling by imposing unequal inheritance of regulators of Notch. Here, we assessed the functional relationship between Notch and ACD in mouse T cell development. To attain immunological specificity, developing T cells must pass through a pivotal stage termed β-selection, which involves Notch signalling and ACD. We assessed functional interactions between Notch and ACD during β-selection using direct presentation of Notch ligands, DL1 and DL4, and pharmacological inhibition of Notch signalling. Contrary to prevailing models, we find Notch controls distribution of Notch1 itself and cell fate determinants, α-Adaptin and Numb. Notch and CXCR4 signalling cooperated to drive polarity during division. Thus, Notch signalling directly orchestrates ACD, and Notch1 is differentially inherited by sibling cells.

scholarly journals Endodermal differentiation is reconstructed by coordination of two parallel signaling systems derived from the stele in roots

2017 ◽  
Author(s):  
Pengxue Li ◽  
Qiaozhi Yu ◽  
Chunmiao Xu ◽  
Xu Gu ◽  
Shilian Qi ◽  
...  
Keyword(s):  
Cell Division ◽  
Cell Fate ◽  
Asymmetric Cell Division ◽  
Cell Types ◽  
Plant Roots ◽  
Synthetic Approach ◽  
Fate Map ◽  
Signaling Systems ◽  
Apoplastic Barrier ◽  
Casparian Strips

AbstractThe plant roots represent the exquisitely controlled cell fate map in which different cell types undergo a complete status transition from stem cell division and initial fate specification, to the terminal differentiation. The endodermis is initially specified in meristem but further differentiates to form Casparian strips (CSs), the apoplastic barrier in the mature zone for the selective transport between stele and outer tissues, and thus is regarded as plant inner skin. In the Arabidopsis thaliana root the transcription factors SHORTROOT (SHR) regulate asymmetric cell division in cortical initials to separate endodermal and cortex cell layer. In this paper, we utilized synthetic approach to examine the reconstruction of fully functional Casparian strips in plant roots. Our results revealed that SHR serves as a master regulator of a hierarchical signaling cascade that, combined with stele-derived small peptides, is sufficient to rebuild the functional CS in non-endodermal cells. This is a demonstration of the deployment of two parallel signaling systems, in which both apoplastic and symplastic communication were employed, for coordinately specifying the endodermal cell fate.

scholarly journals Asymmetric cell division during T cell development controls downstream fate

2015 ◽  
Vol 210 (6) ◽  
pp. 933-950 ◽  
Author(s):  
Kim Pham ◽  
Raz Shimoni ◽  
Mirren Charnley ◽  
Mandy J. Ludford-Menting ◽  
Edwin D. Hawkins ◽  
...  
Keyword(s):  
Cell Division ◽  
T Cell ◽  
Cell Fate ◽  
Asymmetric Cell Division ◽  
T Cell Development ◽  
Cell Development ◽  
Cell Clones ◽  
Fate Determinants ◽  
Cell Fate Determinants ◽  
Selection Stage

During mammalian T cell development, the requirement for expansion of many individual T cell clones, rather than merely expansion of the entire T cell population, suggests a possible role for asymmetric cell division (ACD). We show that ACD of developing T cells controls cell fate through differential inheritance of cell fate determinants Numb and α-Adaptin. ACD occurs specifically during the β-selection stage of T cell development, and subsequent divisions are predominantly symmetric. ACD is controlled by interaction with stromal cells and chemokine receptor signaling and uses a conserved network of polarity regulators. The disruption of polarity by deletion of the polarity regulator, Scribble, or the altered inheritance of fate determinants impacts subsequent fate decisions to influence the numbers of DN4 cells arising after the β-selection checkpoint. These findings indicate that ACD enables the thymic microenvironment to orchestrate fate decisions related to differentiation and self-renewal.

scholarly journals Roles of Actin in the Morphogenesis of the Early Caenorhabditis elegans Embryo

2020 ◽  
Vol 21 (10) ◽  
pp. 3652
Author(s):  
Dureen Samandar Eweis ◽  
Julie Plastino
Keyword(s):  
Cell Division ◽  
Caenorhabditis Elegans ◽  
Asymmetric Cell Division ◽  
Cell Types ◽  
Actin Dynamics ◽  
Actin Binding ◽  
Asymmetric Cell Divisions ◽  
C Elegans ◽  
Asymmetric Divisions ◽  
Different Cell Types

The cell shape changes that ensure asymmetric cell divisions are crucial for correct development, as asymmetric divisions allow for the formation of different cell types and therefore different tissues. The first division of the Caenorhabditis elegans embryo has emerged as a powerful model for understanding asymmetric cell division. The dynamics of microtubules, polarity proteins, and the actin cytoskeleton are all key for this process. In this review, we highlight studies from the last five years revealing new insights about the role of actin dynamics in the first asymmetric cell division of the early C. elegans embryo. Recent results concerning the roles of actin and actin binding proteins in symmetry breaking, cortical flows, cortical integrity, and cleavage furrow formation are described.

scholarly journals Fluctuating fitness shapes the clone-size distribution of immune repertoires

2015 ◽  
Vol 113 (2) ◽  
pp. 274-279 ◽  
Author(s):  
Jonathan Desponds ◽  
Thierry Mora ◽  
Aleksandra M. Walczak
Keyword(s):  
T Cells ◽  
Cell Fate ◽  
Single Cells ◽  
Adaptive Immune System ◽  
Cell Types ◽  
Power Law Distribution ◽  
Clone Size ◽  
Environmental Signals ◽  
Somatic Evolution ◽  
Effective Models

The adaptive immune system relies on the diversity of receptors expressed on the surface of B- and T cells to protect the organism from a vast amount of pathogenic threats. The proliferation and degradation dynamics of different cell types (B cells, T cells, naive, memory) is governed by a variety of antigenic and environmental signals, yet the observed clone sizes follow a universal power-law distribution. Guided by this reproducibility we propose effective models of somatic evolution where cell fate depends on an effective fitness. This fitness is determined by growth factors acting either on clones of cells with the same receptor responding to specific antigens, or directly on single cells with no regard for clones. We identify fluctuations in the fitness acting specifically on clones as the essential ingredient leading to the observed distributions. Combining our models with experiments, we characterize the scale of fluctuations in antigenic environments and we provide tools to identify the relevant growth signals in different tissues and organisms. Our results generalize to any evolving population in a fluctuating environment.

Cell contact induces multiple types of electrical excitability from ascidian two-cell embryos that are cleavage arrested and contain all cell fate determinants

2007 ◽  
Vol 293 (5) ◽  
pp. R1976-R1996
Author(s):  
Motoko Tanaka-Kunishima ◽  
Kunitaro Takahashi ◽  
Fumiyuki Watanabe
Keyword(s):  
Stem Cells ◽  
Cell Fate ◽  
Single Cells ◽  
Muscle Cells ◽  
Cell Types ◽  
Specific Cell ◽  
Cell Type ◽  
Cell Pair ◽  
Fate Determinants ◽  
Cell Fate Determinants

Ascidian early embryonic cells undergo cell differentiation without cell cleavage, thus enabling mixture of cell fate determinants in single cells, which will not be possible in mammalian systems. Either cell in a two-cell embryo (2C cell) has multiple fates and develops into any cell types in a tadpole. To find the condition for controlled induction of a specific cell type, cleavage-arrested cell triplets were prepared in various combinations. They were 2C cells in contact with a pair of anterior neuroectoderm cells from eight-cell embryos (2C-aa triplet), with a pair of presumptive notochordal neural cells (2C-AA triplet), with a pair of presumptive posterior epidermal cells (2C-bb triplet), and with a pair of presumptive muscle cells (2C-BB triplet). The fate of the 2C cell was electrophysiologically identified. When two-cell embryos had been fertilized 3 h later than eight-cell embryos and triplets were formed, the 2C cells became either anterior-neuronal, posterior-neuronal or muscle cells, depending on the cell type of the contacting cell pair. When two-cell embryos had been fertilized earlier than eight-cell embryos, most 2C cells became epidermal. When two- and eight-cell embryos had been simultaneously fertilized, the 2C cells became any one of three cell types described above or the epidermal cell type. Differentiation of the ascidian 2C cell into major cell types was reproducibly induced by selecting the type of contacting cell pair and the developmental time difference between the contacting cell pair and 2C cell. We discuss similarities between cleavage-arrested 2C cells and vertebrate embryonic stem cells and propose the ascidian 2C cell as a simple model for toti-potent stem cells.

scholarly journals When fate follows age: unequal centrosomes in asymmetric cell division

2014 ◽  
Vol 369 (1650) ◽  
pp. 20130466 ◽  
Author(s):  
Jose Reina ◽  
Cayetano Gonzalez
Keyword(s):  
Stem Cells ◽  
Cell Division ◽  
Strong Correlation ◽  
Molecular Mechanisms ◽  
Asymmetric Cell Division ◽  
Current Knowledge ◽  
Cell Types ◽  
Functional Implications ◽  
Different Cell Types ◽  
Review Current

A strong correlation between centrosome age and fate has been reported in some stem cells and progenitors that divide asymmetrically. In some cases, such stereotyped centrosome behaviour is essential to endow stemness to only one of the two daughters, whereas in other cases causality is still uncertain. Here, we present the different cell types in which correlated centrosome age and fate has been documented, review current knowledge on the underlying molecular mechanisms and discuss possible functional implications of this process.

scholarly journals The endoplasmic reticulum is partitioned asymmetrically during mitosis before cell fate selection in proneuronal cells in the early Drosophila embryo

2017 ◽  
Vol 28 (11) ◽  
pp. 1530-1538 ◽  
Author(s):  
Anthony S. Eritano ◽  
Arturo Altamirano ◽  
Sarah Beyeler ◽  
Norma Gaytan ◽  
Mark Velasquez ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Division ◽  
Cell Fate ◽  
Asymmetric Cell Division ◽  
Asymmetric Division ◽  
Drosophila Embryo ◽  
Early Drosophila Embryo ◽  
Dividing Cells ◽  
Fate Determinants ◽  
Selection Of

Asymmetric cell division is the primary mechanism to generate cellular diversity, and it relies on the correct partitioning of cell fate determinants. However, the mechanism by which these determinants are delivered and positioned is poorly understood, and the upstream signal to initiate asymmetric cell division is unknown. Here we report that the endoplasmic reticulum (ER) is asymmetrically partitioned during mitosis in epithelial cells just before delamination and selection of a proneural cell fate in the early Drosophila embryo. At the start of gastrulation, the ER divides asymmetrically into a population of asynchronously dividing cells at the anterior end of the embryo. We found that this asymmetric division of the ER depends on the highly conserved ER membrane protein Jagunal (Jagn). RNA inhibition of jagn just before the start of gastrulation disrupts this asymmetric division of the ER. In addition, jagn-deficient embryos display defects in apical-basal spindle orientation in delaminated embryonic neuroblasts. Our results describe a model in which an organelle is partitioned asymmetrically in an otherwise symmetrically dividing cell population just upstream of cell fate determination and updates previous models of spindle-based selection of cell fate during mitosis.

scholarly journals Fluctuating fitness shapes the clone size distribution of immune repertoires

2015 ◽  
Author(s):  
Jonathan Desponds ◽  
Thierry Mora ◽  
Aleksandra Walczak
Keyword(s):  
T Cells ◽  
Cell Fate ◽  
Single Cells ◽  
Adaptive Immune System ◽  
Cell Types ◽  
Power Law Distribution ◽  
Clone Size ◽  
Environmental Signals ◽  
Somatic Evolution ◽  
Effective Models

The adaptive immune system relies on the diversity of receptors expressed on the surface of B and T-cells to protect the organism from a vast amount of pathogenic threats. The proliferation and degradation dynamics of different cell types (B cells, T cells, naive, memory) is governed by a variety of antigenic and environmental signals, yet the observed clone sizes follow a universal power law distribution. Guided by this reproducibility we propose effective models of somatic evolution where cell fate depends on an effective fitness. This fitness is determined by growth factors acting either on clones of cells with the same receptor responding to specific antigens, or directly on single cells with no regards for clones. We identify fluctuations in the fitness acting specifically on clones as the essential ingredient leading to the observed distributions. Combining our models with experiments we characterize the scale of fluctuations in antigenic environments and we provide tools to identify the relevant growth signals in different tissues and organisms. Our results generalize to any evolving population in a fluctuating environment.

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