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Lee SY, Lim SK, Cha SW, Yoon J, Lee SH, Lee HS, Park JB, Lee JY, Kim SC, Kim J. Inhibition of FGF signaling converts dorsal mesoderm to ventral mesoderm in early Xenopus embryos. Differentiation 2011; 82:99-107. [PMID: 21684060 DOI: 10.1016/j.diff.2011.05.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2010] [Revised: 05/20/2011] [Accepted: 05/24/2011] [Indexed: 11/16/2022]
Abstract
In early vertebrate development, mesoderm induction is a crucial event regulated by several factors including the activin, BMP and FGF signaling pathways. While the requirement of FGF in Nodal/activin-induced mesoderm formation has been reported, the fate of the tissue modulated by these signals is not fully understood. Here, we examined the fate of tissues when exogenous activin was added and FGF signaling was inhibited in animal cap explants of Xenopus embryos. Activin-induced dorsal mesoderm was converted to ventral mesoderm by inhibition of FGF signaling. We also found that inhibiting FGF signaling in the dorsal marginal zone, in vegetal-animal cap conjugates or in the presence of the activin signaling component Smad2, converted dorsal mesoderm to ventral mesoderm. The expression and promoter activities of a BMP responsive molecule, PV.1 and a Spemann organizer, noggin, were investigated while FGF signaling was inhibited. PV.1 expression increased, while noggin decreased. In addition, inhibiting BMP-4 signaling abolished ventral mesoderm formation induced by exogenous activin and FGF inhibition. Taken together, these results suggest that the formation of dorso-ventral mesoderm in early Xenopus embryos is regulated by a combination of FGF, activin and BMP signaling.
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Affiliation(s)
- Sung-Young Lee
- Department of Biochemistry, College of Medicine, Hallym University, ChunCheon, Kangwon-Do, 200-702, Republic of Korea
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Lee SY, Yoon J, Lee HS, Hwang YS, Cha SW, Jeong CH, Kim JI, Park JB, Lee JY, Kim S, Park MJ, Dong Z, Kim J. The function of heterodimeric AP-1 comprised of c-Jun and c-Fos in activin mediated Spemann organizer gene expression. PLoS One 2011; 6:e21796. [PMID: 21829441 PMCID: PMC3146467 DOI: 10.1371/journal.pone.0021796] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Accepted: 06/13/2011] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Activator protein-1 (AP-1) is a mediator of BMP or FGF signaling during Xenopus embryogenesis. However, specific role of AP-1 in activin signaling has not been elucidated during vertebrate development. METHODOLOGY/PRINCIPAL FINDINGS We provide new evidence showing that overexpression of heterodimeric AP-1 comprised of c-jun and c-fos (AP-1(c-Jun/c-Fos)) induces the expression of BMP-antagonizing organizer genes (noggin, chordin and goosecoid) that were normally expressed by high dose of activin. AP-1(c-Jun/c-Fos) enhanced the promoter activities of organizer genes but reduced that of PV.1, a BMP4-response gene. A loss of function study clearly demonstrated that AP-1(c-Jun/c-Fos) is required for the activin-induced organizer and neural gene expression. Moreover, physical interaction of AP-1(c-Jun/c-Fos) and Smad3 cooperatively enhanced the transcriptional activity of goosecoid via direct binding on this promoter. Interestingly, Smad3 mutants at c-Jun binding site failed in regulation of organizer genes, indicating that these physical interactions are specifically necessary for the expression of organizer genes. CONCLUSIONS/SIGNIFICANCE AP-1(c-Jun/c-Fos) plays a specific role in organizer gene expression in downstream of activin signal during early Xenopus embryogenesis.
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Affiliation(s)
- Sung-Young Lee
- Department of Biochemistry, College of Medicine, Hallym University, ChunCheon, Kangwon-Do, Republic of Korea
- The Hormel Institute, University of Minnesota, Austin, Minnesota, United States of America
| | - Jaeho Yoon
- Department of Biochemistry, College of Medicine, Hallym University, ChunCheon, Kangwon-Do, Republic of Korea
| | - Hyun-Shik Lee
- Department of Biochemistry, College of Medicine, Hallym University, ChunCheon, Kangwon-Do, Republic of Korea
- School of Life Sciences, College of Natural Sciences, Kyungpook National University, Daegu, Republic of Korea
| | - Yoo-Seok Hwang
- Department of Anatomy, School of Medicine, Kyungpook National University, Daegu, Republic of Korea
| | - Sang-Wook Cha
- Department of Anatomy, School of Medicine, Kyungpook National University, Daegu, Republic of Korea
| | - Chul-Ho Jeong
- The Hormel Institute, University of Minnesota, Austin, Minnesota, United States of America
- College of Pharmacy, Keimyung University, Daegu, Republic of Korea
| | - Jong-Il Kim
- Department of Biochemistry, College of Medicine, Hallym University, ChunCheon, Kangwon-Do, Republic of Korea
| | - Jae-Bong Park
- Department of Biochemistry, College of Medicine, Hallym University, ChunCheon, Kangwon-Do, Republic of Korea
| | - Jae-Yong Lee
- Department of Biochemistry, College of Medicine, Hallym University, ChunCheon, Kangwon-Do, Republic of Korea
| | - SungChan Kim
- Department of Biochemistry, College of Medicine, Hallym University, ChunCheon, Kangwon-Do, Republic of Korea
| | - Mae Ja Park
- Department of Anatomy, School of Medicine, Kyungpook National University, Daegu, Republic of Korea
| | - Zigang Dong
- The Hormel Institute, University of Minnesota, Austin, Minnesota, United States of America
| | - Jaebong Kim
- Department of Biochemistry, College of Medicine, Hallym University, ChunCheon, Kangwon-Do, Republic of Korea
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Rankin SA, Kormish J, Kofron M, Jegga A, Zorn AM. A gene regulatory network controlling hhex transcription in the anterior endoderm of the organizer. Dev Biol 2011; 351:297-310. [PMID: 21215263 PMCID: PMC3044432 DOI: 10.1016/j.ydbio.2010.11.037] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Revised: 11/15/2010] [Accepted: 11/17/2010] [Indexed: 10/18/2022]
Abstract
The homeobox gene hhex is one of the earliest markers of the anterior endoderm, which gives rise to foregut organs such as the liver, ventral pancreas, thyroid, and lungs. The regulatory networks controlling hhex transcription are poorly understood. In an extensive cis-regulatory analysis of the Xenopus hhex promoter, we determined how the Nodal, Wnt, and BMP pathways and their downstream transcription factors regulate hhex expression in the gastrula organizer. We show that Nodal signaling, present throughout the endoderm, directly activates hhex transcription via FoxH1/Smad2 binding sites in the proximal -0.44 Kb promoter. This positive action of Nodal is suppressed in the ventral-posterior endoderm by Vent 1 and Vent2, homeodomain repressors that are induced by BMP signaling. Maternal Wnt/β-catenin on the dorsal side of the embryo cooperates with Nodal and indirectly activates hhex expression via the homeodomain activators Siamois and Twin. Siamois/Twin stimulate hhex transcription through two mechanisms: (1) they induce the expression of Otx2 and Lim1 and together Siamois, Twin, Otx2, and Lim1 appear to promote hhex transcription through homeobox sites in a Wnt-responsive element located between -0.65 to -0.55 Kb of the hhex promoter. (2) Siamois/Twin also induce the expression of the BMP-antagonists Chordin and Noggin, which are required to exclude Vents from the organizer allowing hhex transcription. This study reveals a complex network regulating anterior endoderm transcription in the early embryo.
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Affiliation(s)
- Scott A. Rankin
- Division of Developmental Biology, Cincinnati Children’s Research Foundation and Department of Pediatrics, College of Medicine, University of Cincinnati, 3333 Burnet Avenue, Cincinnati, Ohio 45229, USA
| | - Jay Kormish
- Division of Developmental Biology, Cincinnati Children’s Research Foundation and Department of Pediatrics, College of Medicine, University of Cincinnati, 3333 Burnet Avenue, Cincinnati, Ohio 45229, USA
| | - Matt Kofron
- Division of Developmental Biology, Cincinnati Children’s Research Foundation and Department of Pediatrics, College of Medicine, University of Cincinnati, 3333 Burnet Avenue, Cincinnati, Ohio 45229, USA
| | - Anil Jegga
- Division of Biomedical Informatics, Cincinnati Children’s Research Foundation and Department of Pediatrics, College of Medicine, University of Cincinnati, 3333 Burnet Avenue, Cincinnati, Ohio 45229, USA
| | - Aaron M. Zorn
- Division of Developmental Biology, Cincinnati Children’s Research Foundation and Department of Pediatrics, College of Medicine, University of Cincinnati, 3333 Burnet Avenue, Cincinnati, Ohio 45229, USA
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Geng X, Xiao L, Tao Q, Hu R, Rupp RAW, Ding X. The Xenopus noggin promoter drives roof-plate specific transcription. Neuroreport 2004; 14:2163-6. [PMID: 14625440 DOI: 10.1097/00001756-200312020-00006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
During vertebrate neural development, inductive signals derived from the roof plate specify dorsal neural cell types of spinal cord as well as adjacent dermomytotome. Noggin has been demonstrated to play a pivotal role in this signaling network but how its expression is regulated remains unclear. To investigate this issue, we identified a 2066 bp Xenopus noggin 5' flanking sequence which recapitulates the roof-plate expression of endogenous gene in transgenic frog tadpoles and we further mapped the roof-plate enhancer to a sequence as short as 79 bp. Our results, therefore, not only shed light on but also provide a powerful tool to the study of neural and somite patterning.
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Affiliation(s)
- Xin Geng
- Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue-yang Road, Shanghai 200031, PR China
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Hwang YS, Lee HS, Roh DH, Cha SW, Lee SY, Seo JJ, Kim J, Park MJ. Active repression of organizer genes by C-terminal domain of PV.1. Biochem Biophys Res Commun 2003; 308:79-86. [PMID: 12890483 DOI: 10.1016/s0006-291x(03)01321-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
PV.1, a homeotic protein, ventralizes dorsal mesoderm and inhibits neuralization by mediating BMP-4 signaling in Xenopus embryo. In our previous report antimorphic PV.1 causes a secondary axis by inducing the ectopic organizer. We analyzed the structure of this transcription factor through domain level assessment. In a phenotype-inducing test, half of the N-terminus at the N-terminal side was unessential for inducing ventralization of embryos. We examined the transacting activity of several regions of PV.1 utilizing GAL4 hybrid system. The C-terminal region/GAL4DBD (DNA binding domain) exhibited strong repressive activity on a reporter gene (operator/promoter/reporter; Gal4-TK-luc) as much as the whole polypeptide/GAL4DBD, whereas the N-terminal region/GAL4DBD showed only modest repression. The results suggest that PV.1 functions as a transcriptional repressor and this repressive activity is localized mostly to the C-terminal region. Additional characterizations of N- and C-terminus with respect to the effects on the expression of other genes are described.
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Affiliation(s)
- Yoo-Seok Hwang
- Department of Anatomy, School of Medicine, Kyungpook National University, Taegu 700-422, South Korea
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Koyano S, Fukui A, Uchida S, Yamada K, Asashima M, Sakuragawa N. Synthesis and release of activin and noggin by cultured human amniotic epithelial cells. Dev Growth Differ 2002; 44:103-12. [PMID: 11940097 DOI: 10.1046/j.1440-169x.2002.00626.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Recent studies suggest that extra-embryonic tissues may be essential sources of early organizing signals for the mouse embryo. In vitro studies of human amniotic epithelial cells (HAEC) have shown that the amnion can produce various biologically active substances. In this study, the synthesis and release of activin A and noggin, and the activin signaling pathway, was investigated in HAEC. Conditioned medium from cultured HAEC contained activin A which was functionally active in Xenopus laevis animal cap assays. Immunohistochemistry, western blotting and reverse transcription-polymerase chain reaction confirmed that HAEC also synthesize and release noggin. Noggin transcripts were induced by the addition of recombinant activin A, and activin A was inhibited by activin antibody except in the presence of cycloheximide (CHX). These data demonstrate that noggin mRNA expression is induced directly by activin A without new protein synthesis, indicating that noggin is a primary response gene. The results suggest that there is an activin signaling pathway in HAEC, and that the human amnion might therefore be involved in neural formation during early development.
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Affiliation(s)
- Satoru Koyano
- Department of Inherited Metabolic Disease, National Institute of Neuroscience, National Center of Neurology and Psychiatry, 4-1-1 Ogawahigashi, Kodaira, Tokyo 187-8502, Japan
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