Proceedings of the National Academy of Sciences, 1991
Activin A, a member of the transforming growth factor beta superfamily, has recently been found t... more Activin A, a member of the transforming growth factor beta superfamily, has recently been found to have potent mesoderm-inducing activity on isolated early Xenopus animal-cap cells. We measured the activin activity of the Xenopus egg extract by using an erythroid-differentiating test with Friend leukemia cells. The results showed that an activin homologue is, indeed, contained in unfertilized eggs and blastulae of Xenopus laevis in a considerable amount. This activity was eluted at the same retention time as human activin A when fractionated by reversed-phase HPLC. Furthermore, the fraction containing erythroid-differentiating factor activity had mesoderm-inducing activity on Xenopus animal-cap cells. The mesoderm-inducing activity of this fraction was suppressed when coincubated with follistatin, an activin-binding protein. These results suggest that an endogenous activin may be a natural mesoderm-inducing factor acting in Xenopus embryogenesis.
Myristoylated alanine-rich C kinase substrate (MARCKS) is an actin-binding, membrane-associated p... more Myristoylated alanine-rich C kinase substrate (MARCKS) is an actin-binding, membrane-associated protein expressed during Xenopus embryogenesis. We analyzed its function in cytoskeletal regulation during gastrulation. Here, we show that blockade of its function impaired morphogenetic movements, including convergent extension. MARCKS was required for control of cell morphology, motility, adhesion, protrusive activity, and cortical actin formation in embryonic cells. We also demonstrate that the noncanonical Wnt pathway promotes the formation of lamellipodia- and filopodia-like protrusions and that MARCKS is necessary for this activity. These findings show that MARCKS regulates the cortical actin formation that is requisite for dynamic morphogenetic movements.
Proceedings of the National Academy of Sciences, 1994
The biological effects of endogenous bone morphogenetic protein 4 (BMP-4), a member of the transf... more The biological effects of endogenous bone morphogenetic protein 4 (BMP-4), a member of the transforming growth factor beta family, on embryonic development of Xenopus laevis were investigated by using a functionally defective mutant of the BMP-4 receptor (delta mTFR11), which blocks the BMP signaling pathway. Injection of delta mTFR11 RNA into either the animal pole area or ventral marginal cells at the two-cell stage induced a dorsal phenotype in the explant of ventral mesoderm with animal pole tissue from stage 10+ embryo, even though the normal fate of this explant is a "mesenchymal ball" containing blood cells. These explants with the dorsal phenotype contained muscle, neural tissue, eye capsule, and cement gland. Northern blot analysis showed an increase of cardiac alpha-actin mRNA and a decrease of T alpha-globin mRNA expression, providing further evidence of a conversion from ventral to dorsal phenotype. Although injection of delta mTFR11 RNA did not induce mesoderm...
Proceedings of the National Academy of Sciences, 1994
Bone morphogenetic proteins (BMPs), which are members of the transforming growth factor beta (TGF... more Bone morphogenetic proteins (BMPs), which are members of the transforming growth factor beta (TGF-beta) superfamily, have been implicated in bone formation and the regulation of early development. To better understand the roles of BMPs in Xenopus laevis embryogenesis, we have cloned a cDNA coding for a serine/threonine kinase receptor that binds BMP-2 and BMP-4. To analyze its function, we attempted to block the BMP signaling pathway in Xenopus embryos by using a dominant-negative mutant of the BMP receptor. When the mutant receptor lacking the putative serine/threonine kinase domain was expressed in ventral blastomeres of Xenopus embryos, these blastomeres were respecified to dorsal mesoderm, eventually resulting in the formation of a secondary body axis. These findings suggest that endogenous BMP-2 and BMP-4 are involved in the dorsal-ventral specification in the embryo and that ventral fate requires induction rather than resulting from an absence of dorsal specification.
Proceedings of the National Academy of Sciences, 1998
In early development of Xenopus laevis, it is known that activities of polypeptide growth factors... more In early development of Xenopus laevis, it is known that activities of polypeptide growth factors are negatively regulated by their binding proteins. In this study, follistatin, originally known as an activin-binding protein, was shown to inhibit all aspects of bone morphogenetic protein (BMP) activity in early Xenopus embryos. Furthermore, using a surface plasmon resonance biosensor, we demonstrated that follistatin can directly interact with multiple BMPs at significantly high affinities. Interestingly, follistatin was found to be noncompetitive with the BMP receptor for ligand binding and to form a trimeric complex with BMP and its receptor. The results suggest that follistatin acts as an organizer factor in early amphibian embryogenesis by inhibiting BMP activities by a different mechanism from that used by chordin and noggin.
Proceedings of the National Academy of Sciences, 2009
Planar cell polarity (PCP) genes are essential for establishing planar cell polarity in both inve... more Planar cell polarity (PCP) genes are essential for establishing planar cell polarity in both invertebrate and vertebrate tissues and are known to regulate cellular morphogenesis and cell movements during development. We focused on Prickle, one of the core components of the PCP pathway, and deleted one of two mouse prickle homologous genes, mpk1 . We found that the deletion of mpk1 gene resulted in early embryonic lethality, between embryonic day (E)5.5 and E6.5, associated with failure of distal visceral endoderm migration and primitive streak formation. The mpk1 −/− epiblast tissue was disorganized, and analyses at the cellular level revealed abnormal cell shapes, mislocalized extracellular matrix (ECM) proteins, and disrupted orientation of mitotic spindles, from which loss of apico-basal (AB) polarity of epiblast cells are suspected. Furthermore, we show mpk1 genetically interacts with another core PCP gene Vangl2/stbm in the epiblast formation, suggesting that PCP components are...
Bone morphogenetic proteins (BMPs) are secreted proteins that interact with cell-surface receptor... more Bone morphogenetic proteins (BMPs) are secreted proteins that interact with cell-surface receptors and are believed to play a variety of important roles during vertebrate embryogenesis. Bmpr, also known as ALK-3 and Brk-1, encodes a type I transforming growth factor-beta (TGF-beta) family receptor for BMP-2 and BMP-4. Bmpr is expressed ubiquitously during early mouse embryogenesis and in most adult mouse tissues. To study the function of Bmpr during mammalian development, we generated Bmpr-mutant mice. After embryonic day 9.5 (E9.5), no homozygous mutants were recovered from heterozygote matings. Homozygous mutants with morphological defects were first detected at E7.0 and were smaller than normal. Morphological and molecular examination demonstrated that no mesoderm had formed in the mutant embryos. The growth characteristics of homozygous mutant blastocysts cultured in vitro were indistinguishable from those of controls; however, embryonic ectoderm (epiblast) cell proliferation wa...
The molecular mechanisms governing the cell behaviors underlying morphogenesis remain a major foc... more The molecular mechanisms governing the cell behaviors underlying morphogenesis remain a major focus of research in both developmental biology and cancer biology. TGF-β ligands control cell fate specification via Smad-mediated signaling. However, their ability to guide cellular morphogenesis in a variety of biological contexts is poorly understood. We report on the discovery of a novel TGF-β signaling-mediated cellular morphogenesis occurring during vertebrate gastrulation. Activin/nodal members of the TGF-β superfamily induce the expression of two genes regulating cell adhesion during gastrulation: Fibronectin Leucine-rich Repeat Transmembrane 3 (FLRT3), a type I transmembrane protein containing extracellular leucine-rich repeats, and the small GTPase Rnd1. FLRT3 and Rnd1 interact physically and modulate cell adhesion during embryogenesis by controlling cell surface levels of cadherin through a dynamin-dependent endocytosis pathway. Our model suggests that cell adhesion can be dynam...
Proceedings of the National Academy of Sciences, 1991
Activin A, a member of the transforming growth factor beta superfamily, has recently been found t... more Activin A, a member of the transforming growth factor beta superfamily, has recently been found to have potent mesoderm-inducing activity on isolated early Xenopus animal-cap cells. We measured the activin activity of the Xenopus egg extract by using an erythroid-differentiating test with Friend leukemia cells. The results showed that an activin homologue is, indeed, contained in unfertilized eggs and blastulae of Xenopus laevis in a considerable amount. This activity was eluted at the same retention time as human activin A when fractionated by reversed-phase HPLC. Furthermore, the fraction containing erythroid-differentiating factor activity had mesoderm-inducing activity on Xenopus animal-cap cells. The mesoderm-inducing activity of this fraction was suppressed when coincubated with follistatin, an activin-binding protein. These results suggest that an endogenous activin may be a natural mesoderm-inducing factor acting in Xenopus embryogenesis.
Myristoylated alanine-rich C kinase substrate (MARCKS) is an actin-binding, membrane-associated p... more Myristoylated alanine-rich C kinase substrate (MARCKS) is an actin-binding, membrane-associated protein expressed during Xenopus embryogenesis. We analyzed its function in cytoskeletal regulation during gastrulation. Here, we show that blockade of its function impaired morphogenetic movements, including convergent extension. MARCKS was required for control of cell morphology, motility, adhesion, protrusive activity, and cortical actin formation in embryonic cells. We also demonstrate that the noncanonical Wnt pathway promotes the formation of lamellipodia- and filopodia-like protrusions and that MARCKS is necessary for this activity. These findings show that MARCKS regulates the cortical actin formation that is requisite for dynamic morphogenetic movements.
Proceedings of the National Academy of Sciences, 1994
The biological effects of endogenous bone morphogenetic protein 4 (BMP-4), a member of the transf... more The biological effects of endogenous bone morphogenetic protein 4 (BMP-4), a member of the transforming growth factor beta family, on embryonic development of Xenopus laevis were investigated by using a functionally defective mutant of the BMP-4 receptor (delta mTFR11), which blocks the BMP signaling pathway. Injection of delta mTFR11 RNA into either the animal pole area or ventral marginal cells at the two-cell stage induced a dorsal phenotype in the explant of ventral mesoderm with animal pole tissue from stage 10+ embryo, even though the normal fate of this explant is a "mesenchymal ball" containing blood cells. These explants with the dorsal phenotype contained muscle, neural tissue, eye capsule, and cement gland. Northern blot analysis showed an increase of cardiac alpha-actin mRNA and a decrease of T alpha-globin mRNA expression, providing further evidence of a conversion from ventral to dorsal phenotype. Although injection of delta mTFR11 RNA did not induce mesoderm...
Proceedings of the National Academy of Sciences, 1994
Bone morphogenetic proteins (BMPs), which are members of the transforming growth factor beta (TGF... more Bone morphogenetic proteins (BMPs), which are members of the transforming growth factor beta (TGF-beta) superfamily, have been implicated in bone formation and the regulation of early development. To better understand the roles of BMPs in Xenopus laevis embryogenesis, we have cloned a cDNA coding for a serine/threonine kinase receptor that binds BMP-2 and BMP-4. To analyze its function, we attempted to block the BMP signaling pathway in Xenopus embryos by using a dominant-negative mutant of the BMP receptor. When the mutant receptor lacking the putative serine/threonine kinase domain was expressed in ventral blastomeres of Xenopus embryos, these blastomeres were respecified to dorsal mesoderm, eventually resulting in the formation of a secondary body axis. These findings suggest that endogenous BMP-2 and BMP-4 are involved in the dorsal-ventral specification in the embryo and that ventral fate requires induction rather than resulting from an absence of dorsal specification.
Proceedings of the National Academy of Sciences, 1998
In early development of Xenopus laevis, it is known that activities of polypeptide growth factors... more In early development of Xenopus laevis, it is known that activities of polypeptide growth factors are negatively regulated by their binding proteins. In this study, follistatin, originally known as an activin-binding protein, was shown to inhibit all aspects of bone morphogenetic protein (BMP) activity in early Xenopus embryos. Furthermore, using a surface plasmon resonance biosensor, we demonstrated that follistatin can directly interact with multiple BMPs at significantly high affinities. Interestingly, follistatin was found to be noncompetitive with the BMP receptor for ligand binding and to form a trimeric complex with BMP and its receptor. The results suggest that follistatin acts as an organizer factor in early amphibian embryogenesis by inhibiting BMP activities by a different mechanism from that used by chordin and noggin.
Proceedings of the National Academy of Sciences, 2009
Planar cell polarity (PCP) genes are essential for establishing planar cell polarity in both inve... more Planar cell polarity (PCP) genes are essential for establishing planar cell polarity in both invertebrate and vertebrate tissues and are known to regulate cellular morphogenesis and cell movements during development. We focused on Prickle, one of the core components of the PCP pathway, and deleted one of two mouse prickle homologous genes, mpk1 . We found that the deletion of mpk1 gene resulted in early embryonic lethality, between embryonic day (E)5.5 and E6.5, associated with failure of distal visceral endoderm migration and primitive streak formation. The mpk1 −/− epiblast tissue was disorganized, and analyses at the cellular level revealed abnormal cell shapes, mislocalized extracellular matrix (ECM) proteins, and disrupted orientation of mitotic spindles, from which loss of apico-basal (AB) polarity of epiblast cells are suspected. Furthermore, we show mpk1 genetically interacts with another core PCP gene Vangl2/stbm in the epiblast formation, suggesting that PCP components are...
Bone morphogenetic proteins (BMPs) are secreted proteins that interact with cell-surface receptor... more Bone morphogenetic proteins (BMPs) are secreted proteins that interact with cell-surface receptors and are believed to play a variety of important roles during vertebrate embryogenesis. Bmpr, also known as ALK-3 and Brk-1, encodes a type I transforming growth factor-beta (TGF-beta) family receptor for BMP-2 and BMP-4. Bmpr is expressed ubiquitously during early mouse embryogenesis and in most adult mouse tissues. To study the function of Bmpr during mammalian development, we generated Bmpr-mutant mice. After embryonic day 9.5 (E9.5), no homozygous mutants were recovered from heterozygote matings. Homozygous mutants with morphological defects were first detected at E7.0 and were smaller than normal. Morphological and molecular examination demonstrated that no mesoderm had formed in the mutant embryos. The growth characteristics of homozygous mutant blastocysts cultured in vitro were indistinguishable from those of controls; however, embryonic ectoderm (epiblast) cell proliferation wa...
The molecular mechanisms governing the cell behaviors underlying morphogenesis remain a major foc... more The molecular mechanisms governing the cell behaviors underlying morphogenesis remain a major focus of research in both developmental biology and cancer biology. TGF-β ligands control cell fate specification via Smad-mediated signaling. However, their ability to guide cellular morphogenesis in a variety of biological contexts is poorly understood. We report on the discovery of a novel TGF-β signaling-mediated cellular morphogenesis occurring during vertebrate gastrulation. Activin/nodal members of the TGF-β superfamily induce the expression of two genes regulating cell adhesion during gastrulation: Fibronectin Leucine-rich Repeat Transmembrane 3 (FLRT3), a type I transmembrane protein containing extracellular leucine-rich repeats, and the small GTPase Rnd1. FLRT3 and Rnd1 interact physically and modulate cell adhesion during embryogenesis by controlling cell surface levels of cadherin through a dynamin-dependent endocytosis pathway. Our model suggests that cell adhesion can be dynam...
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Papers by Naoto UENO