The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform
Yuji Nakajima - One of the best experts on this subject based on the ideXlab platform.
-
Nodal signal is required for morphogenetic movements of Epiblast layer in the pre‐streak chick blastoderm
Development growth & differentiation, 2011Co-Authors: Nariaki Yanagawa, Masahide Sakabe, Hirokazu Sakata, Toshiyuki Yamagishi, Yuji NakajimaAbstract:During axis formation in amniotes, posterior and lateral Epiblast cells in the area pellucida undergo a counter-rotating movement along the midline to form primitive streak (Polonaise movements). Using chick blastoderms, we investigated the signaling involved in this cellular movement in epithelial-Epiblast. In cultured posterior blastoderm explants from stage X to XI embryos, either Lefty1 or Cerberus-S inhibited initial migration of the explants on chamber slides. In vivo analysis showed that inhibition of Nodal signaling by Lefty1 affected the movement of DiI-marked Epiblast cells prior to the formation of primitive streak. In Lefty1-treated embryos without a primitive streak, Brachyury expression showed a patchy distribution. However, SU5402 did not affect the movement of DiI-marked Epiblast cells. Multi-cellular rosette, which is thought to be involved in epithelial morphogenesis, was found predominantly in the posterior half of the Epiblast, and Lefty1 inhibited the formation of rosettes. Three-dimensional reconstruction showed two types of rosette, one with a protruding cell, the other with a ventral hollow. Our results suggest that Nodal signaling may have a pivotal role in the morphogenetic movements of epithelial Epiblast including Polonaise movements and formation of multi-cellular rosette.
-
nodal signal is required for morphogenetic movements of Epiblast layer in the pre streak chick blastoderm
Development Growth & Differentiation, 2011Co-Authors: Nariaki Yanagawa, Masahide Sakabe, Hirokazu Sakata, Toshiyuki Yamagishi, Yuji NakajimaAbstract:During axis formation in amniotes, posterior and lateral Epiblast cells in the area pellucida undergo a counter-rotating movement along the midline to form primitive streak (Polonaise movements). Using chick blastoderms, we investigated the signaling involved in this cellular movement in epithelial-Epiblast. In cultured posterior blastoderm explants from stage X to XI embryos, either Lefty1 or Cerberus-S inhibited initial migration of the explants on chamber slides. In vivo analysis showed that inhibition of Nodal signaling by Lefty1 affected the movement of DiI-marked Epiblast cells prior to the formation of primitive streak. In Lefty1-treated embryos without a primitive streak, Brachyury expression showed a patchy distribution. However, SU5402 did not affect the movement of DiI-marked Epiblast cells. Multi-cellular rosette, which is thought to be involved in epithelial morphogenesis, was found predominantly in the posterior half of the Epiblast, and Lefty1 inhibited the formation of rosettes. Three-dimensional reconstruction showed two types of rosette, one with a protruding cell, the other with a ventral hollow. Our results suggest that Nodal signaling may have a pivotal role in the morphogenetic movements of epithelial Epiblast including Polonaise movements and formation of multi-cellular rosette.
Mindy George-weinstein - One of the best experts on this subject based on the ideXlab platform.
-
Noggin producing, MyoD-positive cells are crucial for eye development
Developmental Biology, 2009Co-Authors: Jacquelyn Gerhart, Christine Neely, Justin Elder, Jessica Pfautz, Karen E. Knudsen, Kevin Duprey, A. Sue Menko, Mindy George-weinsteinAbstract:A subpopulation of cells expresses MyoD mRNA and the cell surface G8 antigen in the Epiblast prior to the onset of gastrulation. When an antibody to the G8 antigen was applied to the Epiblast, labeled cells were later found in the ocular primordia and muscle and non-muscle forming tissues of the eyes. In the lens, retina and periocular mesenchyme, G8-positive cells synthesized MyoD mRNA and the bone morphogenetic protein inhibitor Noggin. MyoD expressing cells were ablated in the Epiblast by labeling them with the G8 MAb and lysing them with complement. Their ablation in the Epiblast resulted in eye defects, including anopthalmia, micropthalmia, altered pigmentation and malformations of the lens and/or retina. The right eye was more severely affected than the left eye. The asymmetry of the eye defects in ablated embryos correlated with differences in the number of residual Noggin producing, MyoD-positive cells in ocular tissues. Exogenously supplied Noggin compensated for the ablated Epiblast cells. This study demonstrates that MyoD expressing cells serve as a Noggin delivery system to regulate the morphogenesis of the lens and optic cup.
-
Cells that express MyoD mRNA in the Epiblast are stably committed to the skeletal muscle lineage
The Journal of cell biology, 2007Co-Authors: Jacquelyn Gerhart, Christine Neely, Justin Elder, Jessica Pfautz, Jordanna Perlman, Luis Narciso, Kersti K. Linask, Karen E. Knudsen, Mindy George-weinsteinAbstract:The Epiblast of the chick embryo contains cells that express MyoD mRNA but not MyoD protein. We investigated whether MyoD-positive (MyoDpos) Epiblast cells are stably committed to the skeletal muscle lineage or whether their fate can be altered in different environments. A small number of MyoDpos Epiblast cells were tracked into the heart and nervous system. In these locations, they expressed MyoD mRNA and some synthesized MyoD protein. No MyoDpos Epiblast cells differentiated into cardiac muscle or neurons. Similar results were obtained when MyoDpos cells were isolated from the Epiblast and microinjected into the precardiac mesoderm or neural plate. In contrast, Epiblast cells lacking MyoD differentiated according to their environment. These results demonstrate that the Epiblast contains both multipotent cells and a subpopulation of cells that are stably committed to the skeletal muscle lineage before the onset of gastrulation. Stable programming in the Epiblast may ensure that MyoDpos cells express similar signaling molecules in a variety of environments.
-
MyoD-positive Epiblast cells regulate skeletal muscle differentiation in the embryo
The Journal of cell biology, 2006Co-Authors: Jacquelyn Gerhart, Christine Neely, Justin Elder, Karen E. Knudsen, Jared Schure, Tage Kvist, Mindy George-weinsteinAbstract:MyoD mRNA is expressed in a subpopulation of cells within the embryonic Epiblast. Most of these cells are incorporated into somites and synthesize Noggin. Ablation of MyoD-positive cells in the Epiblast subsequently results in the herniation of organs through the ventral body wall, a decrease in the expression of Noggin, MyoD, Myf5, and myosin in the somites and limbs, and an increase in Pax-3–positive myogenic precursors. The addition of Noggin lateral to the somites compensates for the loss of MyoD-positive Epiblast cells. Skeletal muscle stem cells that arise in the Epiblast are utilized in the somites to promote muscle differentiation by serving as a source of Noggin.
-
NeuroM and MyoD are Expressed in Separate Subpopulations of Cells in the Pregastrulating Epiblast
Gene expression patterns : GEP, 2005Co-Authors: Robert Strony, Jacquelyn Gerhart, Christine Neely, Jordanna Perlman, Dolores Tornambe, Jeffrey Dare, Benjamin Stewart, Mindy George-weinsteinAbstract:Epiblast cells form skeletal muscle and neurons in culture and some express mRNA for the skeletal muscle specific transcription factor MyoD in vivo. The following experiments were designed to determine whether the neurogenic transcription factor NeuroM is expressed in the Epiblast and if NeuroM and MyoD are present in separate subpopulations of Epiblast cells that can differentiate into neurons and muscle, respectively. In situ hybridization revealed that NeuroM was present in the anterior region of the pregastrulating Epiblast. Some cells with NeuroM were proliferating and expressed two molecules present in neurogenic cells, NCAM and the Zn-12/HNK-1 carbohydrate. The G8 antibody labeled cells with MyoD but not NeuroM. When G8 positive cells were isolated by magnetic cell sorting and placed in culture, nearly all differentiated into skeletal muscle in serum free medium. A subpopulation of cells isolated with antibodies that bound to cells expressing NeuroM formed neurons when cultured in medium supplemented with sera and embryo extract. These experiments demonstrate that NeuroM and MyoD are present in separate subpopulations of cells in the pregastrulating Epiblast. Epiblast cells with NeuroM are more dependent on exogenous factors to differentiate than those with MyoD.
-
Hepatocyte growth factor/scatter factor promotes a switch from E- to N-cadherin in chick embryo Epiblast cells.
Experimental cell research, 1999Co-Authors: Steven M Deluca, Jacquelyn Gerhart, Eric Cochran, Eileen Simak, Jennifer Blitz, Michelle Mattiacci-paessler, Karen Knudsen, Mindy George-weinsteinAbstract:Epiblast cells downregulate E-cadherin and upregulate N-cadherin as they ingress through the primitive streak and when placed in culture. The factors that promote the alteration in cadherin expression during gastrulation are unknown. The effects of hepatocyte growth factor/scatter factor (HGF/SF) on cadherin expression were tested in cultures of prestreak Epiblast cells. HGF/SF decreased the expression of E-cadherin and increased the percentage of cells with N-cadherin and sarcomeric myosin. Cells with N-cadherin but not E-cadherin differentiated into skeletal muscle. HGF/SF also stimulated proliferation and the formation of cellular aggregates. Sensitivity to HGF/SF in vitro depended on the original position of cells within the Epiblast. More cells from the lateral Epiblast switched cadherins and proliferated in response to HGF/SF than medial Epiblast cells. HGF/SF may affect gastrulation by altering cadherin expression, modulating cell adhesion, and stimulating proliferation within the Epiblast.
Nariaki Yanagawa - One of the best experts on this subject based on the ideXlab platform.
-
Nodal signal is required for morphogenetic movements of Epiblast layer in the pre‐streak chick blastoderm
Development growth & differentiation, 2011Co-Authors: Nariaki Yanagawa, Masahide Sakabe, Hirokazu Sakata, Toshiyuki Yamagishi, Yuji NakajimaAbstract:During axis formation in amniotes, posterior and lateral Epiblast cells in the area pellucida undergo a counter-rotating movement along the midline to form primitive streak (Polonaise movements). Using chick blastoderms, we investigated the signaling involved in this cellular movement in epithelial-Epiblast. In cultured posterior blastoderm explants from stage X to XI embryos, either Lefty1 or Cerberus-S inhibited initial migration of the explants on chamber slides. In vivo analysis showed that inhibition of Nodal signaling by Lefty1 affected the movement of DiI-marked Epiblast cells prior to the formation of primitive streak. In Lefty1-treated embryos without a primitive streak, Brachyury expression showed a patchy distribution. However, SU5402 did not affect the movement of DiI-marked Epiblast cells. Multi-cellular rosette, which is thought to be involved in epithelial morphogenesis, was found predominantly in the posterior half of the Epiblast, and Lefty1 inhibited the formation of rosettes. Three-dimensional reconstruction showed two types of rosette, one with a protruding cell, the other with a ventral hollow. Our results suggest that Nodal signaling may have a pivotal role in the morphogenetic movements of epithelial Epiblast including Polonaise movements and formation of multi-cellular rosette.
-
nodal signal is required for morphogenetic movements of Epiblast layer in the pre streak chick blastoderm
Development Growth & Differentiation, 2011Co-Authors: Nariaki Yanagawa, Masahide Sakabe, Hirokazu Sakata, Toshiyuki Yamagishi, Yuji NakajimaAbstract:During axis formation in amniotes, posterior and lateral Epiblast cells in the area pellucida undergo a counter-rotating movement along the midline to form primitive streak (Polonaise movements). Using chick blastoderms, we investigated the signaling involved in this cellular movement in epithelial-Epiblast. In cultured posterior blastoderm explants from stage X to XI embryos, either Lefty1 or Cerberus-S inhibited initial migration of the explants on chamber slides. In vivo analysis showed that inhibition of Nodal signaling by Lefty1 affected the movement of DiI-marked Epiblast cells prior to the formation of primitive streak. In Lefty1-treated embryos without a primitive streak, Brachyury expression showed a patchy distribution. However, SU5402 did not affect the movement of DiI-marked Epiblast cells. Multi-cellular rosette, which is thought to be involved in epithelial morphogenesis, was found predominantly in the posterior half of the Epiblast, and Lefty1 inhibited the formation of rosettes. Three-dimensional reconstruction showed two types of rosette, one with a protruding cell, the other with a ventral hollow. Our results suggest that Nodal signaling may have a pivotal role in the morphogenetic movements of epithelial Epiblast including Polonaise movements and formation of multi-cellular rosette.
Roger A. Pedersen - One of the best experts on this subject based on the ideXlab platform.
-
The role of E-cadherin and integrins in mesoderm differentiation and migration at the mammalian primitive streak
Development (Cambridge England), 1993Co-Authors: Carol A. Burdsal, C H Damsky, Roger A. PedersenAbstract:We have examined the role of cell-cell and cell-extracellular matrix (ECM) interactions during mesoderm differentiation and migration at the primitive streak of the mouse embryo with the use of function-perturbing antibodies. Explants of Epiblast or mesoderm tissue dissected from the primitive streak of 7.5- to 7.8-day mouse embryos were cultured on a fibronectin substratum in serum-free, chemically defined medium. After 16–24 hours in culture, cells in explants of Epiblast exhibited the typical close-packed morphology of epithelia, and the tissue remained as a coherent patch of cells that were shown to express transcripts of the cytokeratin Endo B by in situ analysis. In contrast, cells in explants of primitive streak mesoderm exhibited a greatly flattened, fibroblastic morphology, did not express Endo B transcripts, and migrated away from the center of the explant. As Epiblast cells in vivo undergo the epithelial-mesenchymal transition at the primitive streak, they cease expressing the prominent calcium-sensitive cell adhesion molecule E-cadherin (uvomorulin, Cell-CAM 120/80). We asked whether the loss of E-cadherin expression was a passive result of differentiation or if it might play a more causative role in mesoderm differentiation and migration. Culture with function-perturbing antibodies against E-cadherin caused cells within Epiblast explants to lose cell-cell contacts, to flatten, and to assume a mesenchymal morphology; they were also induced to migrate. Anti-E-cadherin antibodies had no effect on explants of primitive streak mesoderm. In immunofluorescence studies, anti-E-cadherin-treated Epiblast cells ceased to express SSEA-1, a carbohydrate moiety that is lost as mesoderm differentiates from the Epiblast in vivo, and they also ceased to express E-cadherin itself. In contrast, these cells began to express the intermediate filament protein vimentin, a cytoskeletal protein characteristic of the primitive streak mesoderm at this stage of development. As Epiblast cells differentiate into mesoderm, their predominant adhesive interactions change from cell-cell to cell-substratum. Therefore, we also investigated the adhesive interactions between primitive streak tissues and extracellular matrix (ECM) components. Epiblast explants adhered well to fibronectin, more poorly to laminin and type IV collagen, and not at all to vitronectin. In contrast, mesoderm explants attached well to all these proteins. Furthermore, Epiblast, but not mesoderm, displayed an anchorage-dependent viability in culture. After anti-E-cadherin treatment, Epiblast cells that had assumed the mesenchymal morphology did attach to vitronectin, another characteristic shared with primitive streak mesoderm.(ABSTRACT TRUNCATED AT 400 WORDS)
-
clonal analysis of Epiblast fate during germ layer formation in the mouse embryo
Development, 1991Co-Authors: Kirstie A Lawson, Juanito J Meneses, Roger A. PedersenAbstract:The fate of cells in the Epiblast at prestreak and early primitive streak stages has been studied by injecting horseradish peroxidase (HRP) into single cells in situ of 6.7-day mouse embryos and identifying the labelled descendants at midstreak to neural plate stages after one day of culture. Ectoderm was composed of descendants of Epiblast progenitors that had been located in the embryonic axis anterior to the primitive streak. Embryonic mesoderm was derived from all areas of the Epiblast except the distal tip and the adjacent region anterior to it: the most anterior mesoderm cells originated posteriorly, traversing the primitive streak early; labelled cells in the posterior part of the streak at the neural plate stage were derived from extreme anterior axial and paraxial Epiblast progenitors; head process cells were derived from Epiblast at or near the anterior end of the primitive streak. Endoderm descendants were most frequently derived from a region that included, but extended beyond, the region producing the head process: descendants of Epiblast were present in endoderm by the midstreak stage, as well as at later stages. Yolk sac and amnion mesoderm developed from posterolateral and posterior Epiblast. The resulting fate map is essentially the same as those of the chick and urodele and indicates that, despite geometrical differences, topological fate relationships are conserved among these vertebrates. Clonal descendants were not necessarily confined to a single germ layer or to extraembryonic mesoderm, indicating that these lineages are not separated at the beginning of gastrulation. The embryonic axis lengthened up to the neural plate stage by (1) elongation of the primitive streak through progressive incorporation of the expanding lateral and initially more anterior regions of Epiblast and, (2) expansion of the region of Epiblast immediately cranial to the anterior end of the primitive streak. The population doubling time of labelled cells was 7.5 h; a calculated 43% were in, or had completed, a 4th cell cycle, and no statistically significant regional differences in the number of descendants were found. This clonal analysis also showed that (1) growth in the Epiblast was noncoherent and in most regions anisotropic and directed towards the primitive streak and (2) the midline did not act as a barrier to clonal spread, either in the Epiblast in the anterior half of the axis or in the primitive streak. These results taken together with the fate map indicate that, while individual cells in the Epiblast sheet behave independently with respect to their neighbours, morphogenetic movement during germ layer formation is coordinated in the population as a whole.
Jacquelyn Gerhart - One of the best experts on this subject based on the ideXlab platform.
-
Noggin producing, MyoD-positive cells are crucial for eye development
Developmental Biology, 2009Co-Authors: Jacquelyn Gerhart, Christine Neely, Justin Elder, Jessica Pfautz, Karen E. Knudsen, Kevin Duprey, A. Sue Menko, Mindy George-weinsteinAbstract:A subpopulation of cells expresses MyoD mRNA and the cell surface G8 antigen in the Epiblast prior to the onset of gastrulation. When an antibody to the G8 antigen was applied to the Epiblast, labeled cells were later found in the ocular primordia and muscle and non-muscle forming tissues of the eyes. In the lens, retina and periocular mesenchyme, G8-positive cells synthesized MyoD mRNA and the bone morphogenetic protein inhibitor Noggin. MyoD expressing cells were ablated in the Epiblast by labeling them with the G8 MAb and lysing them with complement. Their ablation in the Epiblast resulted in eye defects, including anopthalmia, micropthalmia, altered pigmentation and malformations of the lens and/or retina. The right eye was more severely affected than the left eye. The asymmetry of the eye defects in ablated embryos correlated with differences in the number of residual Noggin producing, MyoD-positive cells in ocular tissues. Exogenously supplied Noggin compensated for the ablated Epiblast cells. This study demonstrates that MyoD expressing cells serve as a Noggin delivery system to regulate the morphogenesis of the lens and optic cup.
-
Cells that express MyoD mRNA in the Epiblast are stably committed to the skeletal muscle lineage
The Journal of cell biology, 2007Co-Authors: Jacquelyn Gerhart, Christine Neely, Justin Elder, Jessica Pfautz, Jordanna Perlman, Luis Narciso, Kersti K. Linask, Karen E. Knudsen, Mindy George-weinsteinAbstract:The Epiblast of the chick embryo contains cells that express MyoD mRNA but not MyoD protein. We investigated whether MyoD-positive (MyoDpos) Epiblast cells are stably committed to the skeletal muscle lineage or whether their fate can be altered in different environments. A small number of MyoDpos Epiblast cells were tracked into the heart and nervous system. In these locations, they expressed MyoD mRNA and some synthesized MyoD protein. No MyoDpos Epiblast cells differentiated into cardiac muscle or neurons. Similar results were obtained when MyoDpos cells were isolated from the Epiblast and microinjected into the precardiac mesoderm or neural plate. In contrast, Epiblast cells lacking MyoD differentiated according to their environment. These results demonstrate that the Epiblast contains both multipotent cells and a subpopulation of cells that are stably committed to the skeletal muscle lineage before the onset of gastrulation. Stable programming in the Epiblast may ensure that MyoDpos cells express similar signaling molecules in a variety of environments.
-
MyoD-positive Epiblast cells regulate skeletal muscle differentiation in the embryo
The Journal of cell biology, 2006Co-Authors: Jacquelyn Gerhart, Christine Neely, Justin Elder, Karen E. Knudsen, Jared Schure, Tage Kvist, Mindy George-weinsteinAbstract:MyoD mRNA is expressed in a subpopulation of cells within the embryonic Epiblast. Most of these cells are incorporated into somites and synthesize Noggin. Ablation of MyoD-positive cells in the Epiblast subsequently results in the herniation of organs through the ventral body wall, a decrease in the expression of Noggin, MyoD, Myf5, and myosin in the somites and limbs, and an increase in Pax-3–positive myogenic precursors. The addition of Noggin lateral to the somites compensates for the loss of MyoD-positive Epiblast cells. Skeletal muscle stem cells that arise in the Epiblast are utilized in the somites to promote muscle differentiation by serving as a source of Noggin.
-
NeuroM and MyoD are Expressed in Separate Subpopulations of Cells in the Pregastrulating Epiblast
Gene expression patterns : GEP, 2005Co-Authors: Robert Strony, Jacquelyn Gerhart, Christine Neely, Jordanna Perlman, Dolores Tornambe, Jeffrey Dare, Benjamin Stewart, Mindy George-weinsteinAbstract:Epiblast cells form skeletal muscle and neurons in culture and some express mRNA for the skeletal muscle specific transcription factor MyoD in vivo. The following experiments were designed to determine whether the neurogenic transcription factor NeuroM is expressed in the Epiblast and if NeuroM and MyoD are present in separate subpopulations of Epiblast cells that can differentiate into neurons and muscle, respectively. In situ hybridization revealed that NeuroM was present in the anterior region of the pregastrulating Epiblast. Some cells with NeuroM were proliferating and expressed two molecules present in neurogenic cells, NCAM and the Zn-12/HNK-1 carbohydrate. The G8 antibody labeled cells with MyoD but not NeuroM. When G8 positive cells were isolated by magnetic cell sorting and placed in culture, nearly all differentiated into skeletal muscle in serum free medium. A subpopulation of cells isolated with antibodies that bound to cells expressing NeuroM formed neurons when cultured in medium supplemented with sera and embryo extract. These experiments demonstrate that NeuroM and MyoD are present in separate subpopulations of cells in the pregastrulating Epiblast. Epiblast cells with NeuroM are more dependent on exogenous factors to differentiate than those with MyoD.
-
Hepatocyte growth factor/scatter factor promotes a switch from E- to N-cadherin in chick embryo Epiblast cells.
Experimental cell research, 1999Co-Authors: Steven M Deluca, Jacquelyn Gerhart, Eric Cochran, Eileen Simak, Jennifer Blitz, Michelle Mattiacci-paessler, Karen Knudsen, Mindy George-weinsteinAbstract:Epiblast cells downregulate E-cadherin and upregulate N-cadherin as they ingress through the primitive streak and when placed in culture. The factors that promote the alteration in cadherin expression during gastrulation are unknown. The effects of hepatocyte growth factor/scatter factor (HGF/SF) on cadherin expression were tested in cultures of prestreak Epiblast cells. HGF/SF decreased the expression of E-cadherin and increased the percentage of cells with N-cadherin and sarcomeric myosin. Cells with N-cadherin but not E-cadherin differentiated into skeletal muscle. HGF/SF also stimulated proliferation and the formation of cellular aggregates. Sensitivity to HGF/SF in vitro depended on the original position of cells within the Epiblast. More cells from the lateral Epiblast switched cadherins and proliferated in response to HGF/SF than medial Epiblast cells. HGF/SF may affect gastrulation by altering cadherin expression, modulating cell adhesion, and stimulating proliferation within the Epiblast.