Analysis of the NAnog, SOX2 and POU5F1 cistromes in human HUES64 cells and FOXA2 in human ESC-derived endodermal cells

Author(s):  
CA Gifford
Keyword(s):  
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Guilhem Reyt ◽  
Priya Ramakrishna ◽  
Isai Salas-González ◽  
Satoshi Fujita ◽  
Ashley Love ◽  
...  

AbstractLignin is a complex polymer deposited in the cell wall of specialised plant cells, where it provides essential cellular functions. Plants coordinate timing, location, abundance and composition of lignin deposition in response to endogenous and exogenous cues. In roots, a fine band of lignin, the Casparian strip encircles endodermal cells. This forms an extracellular barrier to solutes and water and plays a critical role in maintaining nutrient homeostasis. A signalling pathway senses the integrity of this diffusion barrier and can induce over-lignification to compensate for barrier defects. Here, we report that activation of this endodermal sensing mechanism triggers a transcriptional reprogramming strongly inducing the phenylpropanoid pathway and immune signaling. This leads to deposition of compensatory lignin that is chemically distinct from Casparian strip lignin. We also report that a complete loss of endodermal lignification drastically impacts mineral nutrients homeostasis and plant growth.


1986 ◽  
Vol 34 (6) ◽  
pp. 785-793 ◽  
Author(s):  
W E Howe ◽  
F G Klier ◽  
R G Oshima

The intracellular distribution of extra-embryonic endodermal, cytoskeletal proteins A (Endo A) and B (Endo B) was investigated by double-label immunofluorescent microscopy and double-label immunoelectron microscopy. In parietal endodermal cells, the immunofluorescent distribution of Endo B was always coincident with that of Endo A and could be distinguished from vimentin, particularly at the periphery of the cell. At the electron microscopic level, antibodies against both Endo A and Endo B recognized both bundles and individual intermediate filaments. Double-label immunoelectron microscopy was achieved by use of two sizes of colloidal gold particles (5 nm and 20 nm) that were stabilized with secondary antibodies. These results show that Endo A and B are found in the same intermediate filament and probably co-polymerize to form such structures.


1996 ◽  
Vol 199 (4) ◽  
pp. 883-892
Author(s):  
V M Weis ◽  
R P Levine

Mutualistic associations are prevalent in virtually all environments yet relatively little is known about their complex biochemical and molecular integration and regulation. The endosymbiosis between cnidarians such as the sea anemone Anthopleura elegantissima and the photosynthetic dinoflagellate Symbiodinium californium, in which the algal symbionts are housed in vacuoles within animal endodermal cells, is an ideal model for the study of highly integrated associations at the biochemical and molecular levels. This study describes differential protein synthesis between symbiotic A. elegantissima, collected from environments with high levels of light in the intertidal zone and A. elegantissima that naturally lack symbionts (aposymbiotic), collected from nearby deep-shade habitats. Two-dimensional gel electrophoresis profiles of both steady-state and newly synthesized proteins were compared between the two types of animals using scanning densitometry and image analysis. Symbiotic and aposymbiotic animals share a majority of proteins; however, striking differences in several abundant proteins in steady-state profiles occur. Two proteins are unique to symbiotic animals, one at 32 kDa with an isoelectric point (pI) of 7.9 and another at 31 kDa, pI 6.3. Levels of six proteins with an apparent molecular mass of 25 kDa and pI values ranging from 4.8 to 5.5 are greatly enhanced in aposymbiotic animals. Furthermore, profiles of newly synthesized proteins from symbiotic animals contain a unique cluster of proteins ranging from 25 to 30 kDa and pI 6.6 to 6.9. These marked differences in protein profiles must be a reflection either of underlying differences in the regulation of gene expression or in post-translational modification of common proteins. Identifying the symbiosis-specific products present in A. elegantissima and identifying the inter-partner signaling and cues that result in differential expression will provide an insight into the understanding of these highly integrated associations.


Development ◽  
1995 ◽  
Vol 121 (12) ◽  
pp. 4137-4148 ◽  
Author(s):  
O. Behrendtsen ◽  
C.M. Alexander ◽  
Z. Werb

The outgrowth of parietal endoderm (PE) cells from precursor endodermal cells is one of the first differentiation events that occur in mouse embryos. We have analyzed the molecular determinants of this process by placing isolated inner cell masses (ICMs) on defined extracellular matrix substrata in microdrop cultures. Differentiation and outgrowth of PE required a fibronectin substratum. Laminin supported the adhesion and outgrowth of visceral endoderm (VE) and actively suppressed the differentiation of PE in mixtures of fibronectin and laminin. Collagen type IV, gelatin, vitronectin or entactin supported little or no endodermal outgrowth. Trophectoderm (TE) cells have been implied to be important in PE induction in vivo. We found that recombination of ICMs in culture with TE cells, or with medium conditioned by TE cells, greatly increased the differentiation of PE. TE cells stimulated PE outgrowth on substrata other than fibronectin. One cytokine secreted by trophoblast and endodermal cells, parathyroid hormone-related peptide (PTHrP), was critical for outgrowth on any substratum. A function-perturbing antibody to PTHrP reduced the number of PE cells, whereas the addition of PTHrP increased that number. Furthermore, addition of PTHrP changed the substratum requirements for outgrowth, making laminin, vitronectin and low concentrations of fibronectin permissive for PE outgrowth. Immunostaining with anti-integrin antibodies showed that fully differentiated PE cells outgrowing on fibronectin expressed alpha 5, alpha 6 and alpha v beta 3 integrins. However, analysis of outgrowths in the presence of function-perturbing antibodies to alpha 5, alpha 6 and alpha v beta 3 integrins showed that these integrins directed PE outgrowth only on fibronectin, laminin and vitronectin substrata, respectively. We have shown that there is a cooperative interplay of extracellular matrix, integrins and PTHrP that modulates PE outgrowth.


Development ◽  
1974 ◽  
Vol 32 (2) ◽  
pp. 445-459
Author(s):  
B. Levak-Švajger ◽  
A. Švajger

Single germ layers (or combinations of two of them) were isolated from the primitive streak and the head-fold stage rat embryos and grown for 15 days under the kidney capsule of syngeneic adult animals. The resulting teratomas were examined histologically for the presence of mature tissues, with special emphasis on derivatives of the primitive gut. Ectoderm isolated together with the initial mesodermal wings at the primitive streak stage gave rise to tissue derivatives of all three definitive germ layers. Derivatives of the primitive gut were regularly present in these grafts. At the head-fold stage, isolated ectoderm (including the region of the primitive streak) differentiated into ectodermal and mesodermal derivatives only. Endoderm isolated at the primitive streak stage did not develop when grafted and was always completely resorbed. At the head-fold stage, however, definitive endoderm differentiated into derivatives of the primitive gut if grafted together with adjacent mesoderm. These findings indirectly suggest the migration of prospective endodermal cells from the primitive ectoderm, and therefore a general analogy with the course of events during gastrulation in the chick blastoderm.


Development ◽  
2002 ◽  
Vol 129 (7) ◽  
pp. 1729-1738 ◽  
Author(s):  
Kaoru S. Imai ◽  
Nori Satoh ◽  
Yutaka Satou

In early Ciona savignyi embryos, nuclear localization of β-catenin is the first step of endodermal cell specification, and triggers the activation of various target genes. A cDNA for Cs-FGF4/6/9, a gene activated downstream of β-catenin signaling, was isolated and shown to encode an FGF protein with features of both FGF4/6 and FGF9/20. The early embryonic expression of Cs-FGF4/6/9 was transient and the transcript was seen in endodermal cells at the 16- and 32-cell stages, in notochord and muscle cells at the 64-cell stage, and in nerve cord and muscle cells at the 110-cell stage; the gene was then expressed again in cells of the nervous system after neurulation. When the gene function was suppressed with a specific antisense morpholino oligo, the differentiation of mesenchyme cells was completely blocked, and the fate of presumptive mesenchyme cells appeared to change into that of muscle cells. The inhibition of mesenchyme differentiation was abrogated by coinjection of the morpholino oligo and synthetic Cs-FGF4/6/9 mRNA. Downregulation of β-catenin nuclear localization resulted in the absence of mesenchyme cell differentiation due to failure of the formation of signal-producing endodermal cells. Injection of synthetic Cs-FGF4/6/9 mRNA in β-catenin-downregulated embryos evoked mesenchyme cell differentiation. These results strongly suggest that Cs-FGF4/6/9 produced by endodermal cells acts an inductive signal for the differentiation of mesenchyme cells. On the other hand, the role of Cs-FGF4/6/9 in the induction of notochord cells is partial; the initial process of the induction was inhibited by Cs-FGF4/6/9 morpholino oligo, but notochord-specific genes were expressed later to form a partial notochord.


Development ◽  
2002 ◽  
Vol 129 (2) ◽  
pp. 275-286 ◽  
Author(s):  
Tazu O. Aoki ◽  
Nicolas B. David ◽  
Gabriella Minchiotti ◽  
Laure Saint-Etienne ◽  
Thomas Dickmeis ◽  
...  

Endoderm originates from a large endomesodermal field requiring Nodal signalling. The mechanisms that ensure segregation of endoderm from mesoderm are not fully understood. We first show that the timing and dose of Nodal activation are crucial for endoderm formation and the endoderm versus mesoderm fate choice, because sustained Nodal signalling is required to ensure endoderm formation but transient signalling is sufficient for mesoderm formation. In zebrafish, downstream of Nodal signals, three genes encoding transcription factors (faust, bonnie and clyde and the recently identified gene casanova) are required for endoderm formation and differentiation. However their positions within the pathway are not completely established. In the present work, we show that casanova is the earliest specification marker for endodermal cells and that its expression requires bonnie and clyde. Furthermore, we have analysed the molecular activities of casanova on endoderm formation and found that it can induce endodermal markers and repress mesodermal markers during gastrulation, as well as change the fate of marginal blastomeres to endoderm. Overexpression of casanova also restores endoderm markers in the absence of Nodal signalling. In addition, casanova efficiently restores later endodermal differentiation in these mutants, but this process requires, in addition, a partial activation of Nodal signalling.


The transport of immunoglobulins from mother to foetus and newly born mammal involves selective events which are independent of molecular size, related to immunoglobulin class, structure, and species of origin, and involve considerable protein degradation. Such events are briefly described as background information to a discussion of how selection of proteins might take place during transport across the cellular barriers concerned, namely the yolk sac splanchnopleur, chorio-allantoic placenta, and small intestine. Until recently the Brambell hypothesis has been the most favoured explanation. This implies that selection occurs intracellularly, within endodermal cells of the yolk sac splanchnopleur and small intestine, and within the syncytiotrophoblast of the chorio-allantoic placenta, of certain species. It also suggests that specific receptors are present which give attached proteins protection from degradation when the vesicles containing them fuse with lysosomes; such protected proteins are then liberated from the vesicle by exocytosis. This hypothesis is examined in the light of what is now known about the mechanism of uptake and transport of proteins by the endodermal cells and syncytiotrophoblast. It is suggested that rather than being an intracellular event, involving protection from proteolytic degradation, selection takes place at the cell surface. Evidence is presented, some direct and some circumstantial, that proteins may be selectively endocytosed by coated micropinocytotic vesicles, and non-selectively endocytosed through a complex apical canalicular system leading to macropinocytotic vesicle formation. In the small intestine of the suckling rat these two processes appear to be segregated, selective uptake occurring in the proximal half and non-selective uptake occurring in the distal half. In the endodermal cells of the rabbit yolk sac splanchnopleur, and by implication in the syncytiotrophoblast of man and monkey, it is suggested that both selective, and non-selective, uptake of protein occurs. Non-selective uptake into macropinocytotic vesicles is regarded as an event leading to complete degradation of all contained protein and functioning so as to supply the foetus and newly born mammal with essential amino acids. Selective uptake into coated micropinocytotic vesicles is regarded as an event leading to the transport of immunoglobulins across the cell without any contact with lysosomes, and functioning so as to supply the newly born mammal with protection against invasive organisms. Specific receptors are still required but only for the initial uptake and segregation of proteins into coated micropinocytotic vesicles. The role which the glycocalyx might have in such selective binding of proteins is considered and possible difficulties in characterization of specific receptors brought to light in view of the likely overwhelming need for non-specific binding to effect non-selective uptake.


1982 ◽  
Vol 2 (3) ◽  
pp. 331-337
Author(s):  
W E Howe ◽  
R G Oshima

A derivative, FOT5, of the F9 murine embryonal carcinoma cell line which is resistant to ouabain and thioguanine was fused with a near diploid parietal endodermal cell line, PFHR9, Hybrid clones (ENEC1 to ENEC5) were isolated in HAT Medium containing ouabain at a frequency of approximately 2 x 10(-4). The DNA contents and chromosome number of the ENEC hybrids were approximately the sum of those of the parents. Five hybrid cell lines examined in detail expressed the following parietal endodermal functions: plasminogen activator activity, basement membrane proteins, and endodermal cytoskeletal proteins. Embryonal carcinoma characteristic functions (tumorigenicity, a stage specific embryonic antigen, and high alkaline phosphatase activity) were extinguished in the hybrids. No hybrid clones with embryonal carcinoma morphology were observed among 1,358 hybrid clones examined. Hybrids, propagated for over 100 generations, continued to express endodermal functions and not embryonal carcinoma functions. The coordinate expression of endodermal functions and the extinction of embryonal carcinoma functions in the ENEC hybrids suggest that the parietal endodermal cells contain diffusible activities which extinguish embryonal carcinoma functions and possibly cause the embryonal carcinoma genome to express parietal endodermal characteristics.


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