The nematode even-skipped homolog vab-7 regulates gonad and vulva position in Pristionchus pacificus

Development ◽  
2001 ◽  
Vol 128 (2) ◽  
pp. 253-261 ◽  
Author(s):  
B. Jungblut ◽  
R.J. Sommer

In free-living nematodes, developmental processes like the formation of the vulva, can be studied at a cellular level. Cell lineage and ablation studies have been carried out in various nematode species and multiple changes in vulval patterning have been identified. In Pristionchus pacificus, vulva formation differs from Caenorhabditis elegans with respect to several autonomous and conditional aspects of cell fate specification. To understand the molecular basis of these evolutionary changes, we have performed a genetic analysis of vulva formation in P. pacificus. Here, we describe two mutants where the vulva is shifted posteriorly, affecting which precursor cells will form vulval tissue in P. pacificus. Mutant animals show a concomitant posterior displacement of the gonadal anchor cell, indicating that the gonad and the vulva are affected in a similar way. We show that mutations in the even-skipped homolog of nematodes, vab-7, cause these posterior displacements. In addition, cell ablation studies in the vab-7 mutant indicate that the altered position of the gonad not only changes the cell fate pattern but also the developmental competence of vulval precursor cells. Investigation of Cel-vab-7 mutant animals showed a similar but weaker vulva defective phenotype to the one described for Ppa-vab-7.

Development ◽  
1991 ◽  
Vol 113 (2) ◽  
pp. 495-501 ◽  
Author(s):  
J. Render

Cell fate specification in the gastropod mollusc Ilyanassa obsoleta involves both cell autonomous and inductive mechanisms, which depend on determinants localized first in the polar lobe and then in the D quadrant of the embryo. A complete cell lineage is lacking for this embryo and is essential for a critical interpretation of previous experimental results and an analysis of the mechanisms at the molecular level. Lineages of the first quartet micromeres were followed using Lucifer Yellow dextran as a tracer. The tracer was injected into individual first quartet micromeres using iontophoresis and patterns of fluorescence were analyzed in the larva after 8 days of development. Fluorescence was limited to head structures, including eyes, tentacles and velum. Structures on the left side were derived from 1a and 1d micromeres; 1a gave rise to the left eye, including the lens. Right side structures were derived from the 1c micromere and 1b contributed to the apical plate between the eyes and symmetrically to both sides of the velum. First quartet lineage data are compared with results from previous cell ablation experiments and with lineage data from other species.


Author(s):  
Jesús Chimal-Monroy ◽  
Diana María Escalante-Alcalde

Dr. Maria-Elena Torres-Padilla's research is focused on how cell fate arises from a single-cell embryo, the fertilized egg or zygote. After the initial divisions, cell potency becomes restricted, originating the first cell lineage fates. She studies how epigenetic information controls transitions in cell identity and cellular reprogramming during embryonic development. Currently, she is the founding Director of the Institute of Epigenetics and Stem Cells, Helmholtz Centre, and Professor of Stem Cell Biology at the LMU in Munich. In this interview, Dr. Maria-Elena Torres-Padilla talks to us about her beginnings in the biology field in Mexico. She also tells us about how she became interested in the control of genome regulation within the nucleus during the transition from totipotency to pluripotency and how the control of gene regulation and chromatin organization during the early stages of cell fate decision in the one-cell embryo occurs. She considers that science has no borders; visiting Mexico gives her the possibility to discuss her work with colleagues and the new generation of students trained in Mexico.


Development ◽  
2000 ◽  
Vol 127 (15) ◽  
pp. 3295-3303 ◽  
Author(s):  
B. Jungblut ◽  
R.J. Sommer

Vulva development differs between Caenorhabditis elegans and Pristionchus pacificus in several ways. Seven of 12 ventral epidermal cells in P. pacificus die of apoptosis, whereas homologous cells in C. elegans fuse with the hypodermal syncytium. Vulva induction is a one-step process in C. elegans, but requires a continuous interaction between the gonad and the epidermis in P. pacificus. Here we describe several novel cell-cell interactions in P. pacificus, focusing on the vulva precursor cell P8.p and the mesoblast M. P8.p in P. pacificus, unlike its homologous cell in C. elegans, is incompetent to respond to gonadal signaling in the absence of other vulva precursor cells, but can respond to lateral signaling from a neighboring vulval precursor. P8.p provides an inhibitory signal that determines the developmental competence of P(5,7).p. This lateral inhibition acts via the mesoblast M and is regulated by the homeotic gene Ppa-mab-5. In Ppa-mab-5 mutants, M is misspecified and provides inductive signaling to the vulval precursor cells, including P8.p. Taken together, vulva development in P. pacificus displays novel cell-cell interactions involving the mesoblast M and P8.p. In particular, P8.p represents a new ventral epidermal cell type, which is characterized by novel interactions and a specific response to gonadal signaling.


2018 ◽  
Author(s):  
Lénaïg Défachelles ◽  
Anna E. Russo ◽  
Christian R. Nelson ◽  
Needhi Bhalla

ABSTRACTSpindle checkpoint strength is dictated by three criteria: the number of unattached kinetochores, cell volume and cell fate. We show that the conserved AAA-ATPase, PCH-2/TRIP13, which remodels the checkpoint effector Mad2 from an active conformation to an inactive one, controls checkpoint strength in C. elegans. When we manipulate embryos to decrease cell volume, PCH-2 is no longer required for the spindle checkpoint or recruitment of Mad2 at unattached kinetochores. This role in checkpoint strength is not limited to large cells: the stronger checkpoint in germline precursor cells also depends on PCH-2. PCH-2 is enriched in germline precursor cells and this enrichment relies on conserved factors that induce asymmetry in the early embryo. Finally, the stronger checkpoint in germline precursor cells is regulated by CMT-1, the ortholog of p31comet, which is required for both PCH-2’s localization to unattached kinetochores and its enrichment in germline precursor cells. Thus, PCH-2, likely by regulating the availability of inactive Mad2 at and near unattached kinetochores, governs checkpoint strength. This role may be specifically relevant in scenarios where maintaining genomic stability is particularly challenging, such as in oocytes and early embryos enlarged for developmental competence and germline cells that maintain immortality.


Author(s):  
Francesca Pagani ◽  
Elisa Tratta ◽  
Patrizia Dell’Era ◽  
Manuela Cominelli ◽  
Pietro Luigi Poliani

AbstractEarly B-cell factor-1 (EBF1) is a transcription factor with an important role in cell lineage specification and commitment during the early stage of cell maturation. Originally described during B-cell maturation, EBF1 was subsequently identified as a crucial molecule for proper cell fate commitment of mesenchymal stem cells into adipocytes, osteoblasts and muscle cells. In vessels, EBF1 expression and function have never been documented. Our data indicate that EBF1 is highly expressed in peri-endothelial cells in both tumor vessels and in physiological conditions. Immunohistochemistry, quantitative reverse transcription polymerase chain reaction (RT-qPCR) and fluorescence-activated cell sorting (FACS) analysis suggest that EBF1-expressing peri-endothelial cells represent bona fide pericytes and selectively express well-recognized markers employed in the identification of the pericyte phenotype (SMA, PDGFRβ, CD146, NG2). This observation was also confirmed in vitro in human placenta-derived pericytes and in human brain vascular pericytes (HBVP). Of note, in accord with the key role of EBF1 in the cell lineage commitment of mesenchymal stem cells, EBF1-silenced HBVP cells showed a significant reduction in PDGFRβ and CD146, but not CD90, a marker mostly associated with a prominent mesenchymal phenotype. Moreover, the expression levels of VEGF, angiopoietin-1, NG2 and TGF-β, cytokines produced by pericytes during angiogenesis and linked to their differentiation and activation, were also significantly reduced. Overall, the data suggest a functional role of EBF1 in the cell fate commitment toward the pericyte phenotype.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Tim Liebisch ◽  
Armin Drusko ◽  
Biena Mathew ◽  
Ernst H. K. Stelzer ◽  
Sabine C. Fischer ◽  
...  

AbstractDuring the mammalian preimplantation phase, cells undergo two subsequent cell fate decisions. During the first decision, the trophectoderm and the inner cell mass are formed. Subsequently, the inner cell mass segregates into the epiblast and the primitive endoderm. Inner cell mass organoids represent an experimental model system, mimicking the second cell fate decision. It has been shown that cells of the same fate tend to cluster stronger than expected for random cell fate decisions. Three major processes are hypothesised to contribute to the cell fate arrangements: (1) chemical signalling; (2) cell sorting; and (3) cell proliferation. In order to quantify the influence of cell proliferation on the observed cell lineage type clustering, we developed an agent-based model accounting for mechanical cell–cell interaction, i.e. adhesion and repulsion, cell division, stochastic cell fate decision and cell fate heredity. The model supports the hypothesis that initial cell fate acquisition is a stochastically driven process, taking place in the early development of inner cell mass organoids. Further, we show that the observed neighbourhood structures can emerge solely due to cell fate heredity during cell division.


2012 ◽  
Vol 2012 ◽  
pp. 1-18 ◽  
Author(s):  
Elisa Dorantes-Acosta ◽  
Rosana Pelayo

Acute leukemias are the most common cancer in childhood and characterized by the uncontrolled production of hematopoietic precursor cells of the lymphoid or myeloid series within the bone marrow. Even when a relatively high efficiency of therapeutic agents has increased the overall survival rates in the last years, factors such as cell lineage switching and the rise of mixed lineages at relapses often change the prognosis of the illness. During lineage switching, conversions from lymphoblastic leukemia to myeloid leukemia, or vice versa, are recorded. The central mechanisms involved in these phenomena remain undefined, but recent studies suggest that lineage commitment of plastic hematopoietic progenitors may be multidirectional and reversible upon specific signals provided by both intrinsic and environmental cues. In this paper, we focus on the current knowledge about cell heterogeneity and the lineage switch resulting from leukemic cells plasticity. A number of hypothetical mechanisms that may inspire changes in cell fate decisions are highlighted. Understanding the plasticity of leukemia initiating cells might be fundamental to unravel the pathogenesis of lineage switch in acute leukemias and will illuminate the importance of a flexible hematopoietic development.


The homeotic genes specify the development of specific groups of precursor cells. They establish the correct state of determination of the different primordia. Cell lineage analysis has been particularly useful in studying the mode of action of homeotic genes. The main findings are: (i) most, perhaps all, the homeotic genes are required by every cell of the corresponding primordium (that is, they are cell autonomous); (ii) they act on anatomical units defined by compartment boundaries and including one or more compartments, (iii) most, but not all, homeotic genes are required until the end of the larval period; (iv) the homeotic genes act in combination so that the appropriate development of a given primordium may be established by the contribution of several homeotic genes.


Development ◽  
1992 ◽  
Vol 116 (4) ◽  
pp. 943-952 ◽  
Author(s):  
X. Cui ◽  
C.Q. Doe

Cell diversity in the Drosophila central nervous system (CNS) is primarily generated by the invariant lineage of neural precursors called neuroblasts. We used an enhancer trap screen to identify the ming gene, which is transiently expressed in a subset of neuroblasts at reproducible points in their cell lineage (i.e. in neuroblast ‘sublineages’), suggesting that neuroblast identity can be altered during its cell lineage. ming encodes a predicted zinc finger protein and loss of ming function results in precise alterations in CNS gene expression, defects in axonogenesis and embryonic lethality. We propose that ming controls cell fate within neuroblast cell lineages.


Development ◽  
1997 ◽  
Vol 124 (20) ◽  
pp. 4133-4141 ◽  
Author(s):  
H. Kato ◽  
Y. Taniguchi ◽  
H. Kurooka ◽  
S. Minoguchi ◽  
T. Sakai ◽  
...  

Notch is involved in the cell fate determination of many cell lineages. The intracellular region (RAMIC) of Notch1 transactivates genes by interaction with a DNA binding protein RBP-J. We have compared the activities of mouse RAMIC and its derivatives in transactivation and differentiation suppression of myogenic precursor cells. RAMIC comprises two separate domains, IC for transactivation and RAM for RBP-J binding. Although the physical interaction of IC with RBP-J was much weaker than with RAM, transactivation activity of IC was shown to involve RBP-J by using an RBP-J null mutant cell line. IC showed differentiation suppression activity that was generally comparable to its transactivation activity. The RBP-J-VP16 fusion protein, which has strong transactivation activity, also suppressed myogenesis of C2C12. The RAM domain, which has no other activities than binding to RBP-J, synergistically stimulated transactivation activity of IC to the level of RAMIC. The RAM domain was proposed to compete with a putative co-repressor for binding to RBP-J because the RAM domain can also stimulate the activity of RBP-J-VP16. These results taken together, indicate that differentiation suppression of myogenic precursor cells by Notch signalling is due to transactivation of genes carrying RBP-J binding motifs.


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