1
|
Zhao P, Peng M, Zhang S, Dong Z, Liu M, Xing X, Shi Y, Li H, Chen L. Alternative splicing of the conserved drug-resistant orthologue FpNcb2 is associated with its nuclear accumulation of products and full virulence of Fusarium pseudograminearum. PEST MANAGEMENT SCIENCE 2024. [PMID: 38860488 DOI: 10.1002/ps.8219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 05/02/2024] [Accepted: 05/20/2024] [Indexed: 06/12/2024]
Abstract
BACKGROUND Negative cofactor 2 NC2β (Ncb2 or Dr1) is the beta subunit of a conserved heterodimeric regulator of transcription negative cofactor 2 (NC2) complex that has been identified as key regulator of drug resistance in model fungi. However, its role in plant pathogens is still unclear. RESULTS We identified an NC2β orthologue, FpNcb2, in Fusarium pseudograminearum, which is not only a significant regulatory function in drug resistance, but also essential for growth, conidiation and penetration. Moreover, FpNcb2 undergoes alternative splicing which creates two mRNA isoforms. As a putative CCAAT binding protein, FpNcb2 concentrates in the nuclei, contributing to the expression of two spliced mRNA of FpNcb2 in hypha, conidiophores and conidia, with exception of FpNcb2ISOA in germlings. Expression of each spliced mRNA of FpNcb2 in Δfpncb2 mutant could full complement the defects on growth, conidiation and fungicides sensitivity to that of wild type. However, FpNcb2ISOA and FpNcb2ISOB have different effects on virulence. FpNcb2 acts as a regulator for the transcription of some genes encoding drug efflux and hydrolases. CONCLUSION Our analysis showed the existence of alternative mRNA splicing in the NC2β orthologue, which is associated with protein subcellular localization and fungal virulence. The further elucidation of the target genes of NC2β will provide insights into the potential regulation mechanisms in the antifungal resistance and pathogenesis of F. pseudograminearum. © 2024 Society of Chemical Industry.
Collapse
Affiliation(s)
- Peiyi Zhao
- College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Mengya Peng
- College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Shiyu Zhang
- College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Zaifang Dong
- College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Min Liu
- College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Xiaoping Xing
- College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Yan Shi
- College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Honglian Li
- College of Plant Protection, Henan Agricultural University, Zhengzhou, China
- National Key Laboratory of Wheat and Maize Crop Science, Zhengzhou, China
| | - Linlin Chen
- College of Plant Protection, Henan Agricultural University, Zhengzhou, China
- National Key Laboratory of Wheat and Maize Crop Science, Zhengzhou, China
| |
Collapse
|
2
|
Yang BA, da Rocha AM, Newton I, Shcherbina A, Wong SW, Fraczek PM, Larouche JA, Hiraki HL, Baker BM, Shin JW, Takayama S, Thouless MD, Aguilar CA. Manipulation of the nucleoscaffold potentiates cellular reprogramming kinetics. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.12.532246. [PMID: 36993714 PMCID: PMC10055010 DOI: 10.1101/2023.03.12.532246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Somatic cell fate is an outcome set by the activities of specific transcription factors and the chromatin landscape and is maintained by gene silencing of alternate cell fates through physical interactions with the nuclear scaffold. Here, we evaluate the role of the nuclear scaffold as a guardian of cell fate in human fibroblasts by comparing the effects of transient loss (knockdown) and mutation (progeria) of functional Lamin A/C, a core component of the nuclear scaffold. We observed that Lamin A/C deficiency or mutation disrupts nuclear morphology, heterochromatin levels, and increases access to DNA in lamina-associated domains. Changes in Lamin A/C were also found to impact the mechanical properties of the nucleus when measured by a microfluidic cellular squeezing device. We also show that transient loss of Lamin A/C accelerates the kinetics of cellular reprogramming to pluripotency through opening of previously silenced heterochromatin domains while genetic mutation of Lamin A/C into progerin induces a senescent phenotype that inhibits the induction of reprogramming genes. Our results highlight the physical role of the nuclear scaffold in safeguarding cellular fate.
Collapse
Affiliation(s)
- Benjamin A. Yang
- Dept. of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | | | - Isabel Newton
- Dept. of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Anna Shcherbina
- Dept. of Biomedical Informatics, Stanford University, Palo Alto, CA 94305, USA
| | - Sing-Wan Wong
- Dept. of Pharmacology and Biomedical Engineering, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Paula M. Fraczek
- Dept. of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jacqueline A. Larouche
- Dept. of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Harrison L. Hiraki
- Dept. of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Brendon M. Baker
- Dept. of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jae-Won Shin
- Dept. of Pharmacology and Biomedical Engineering, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Shuichi Takayama
- Wallace Coulter Dept. of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332
| | - M. D. Thouless
- Dept. of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
- Dept. of Materials Science & Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Carlos A. Aguilar
- Dept. of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI 48109, USA
- Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, MI 48109, USA
| |
Collapse
|
3
|
Role of the TATA-box binding protein (TBP) and associated family members in transcription regulation. Gene X 2022; 833:146581. [PMID: 35597524 DOI: 10.1016/j.gene.2022.146581] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 04/18/2022] [Accepted: 05/16/2022] [Indexed: 11/20/2022] Open
Abstract
The assembly of transcription complexes on eukaryotic promoters involves a series of steps, including chromatin remodeling, recruitment of TATA-binding protein (TBP)-containing complexes, the RNA polymerase II holoenzyme, and additional basal transcription factors. This review describes the transcriptional regulation by TBP and its corresponding homologs that constitute the TBP family and their interactions with promoter DNA. The C-terminal core domain of TBP is highly conserved and contains two structural repeats that fold into a saddle-like structure, essential for the interaction with the TATA-box on DNA. Based on the TBP C-terminal core domain similarity, three TBP-related factors (TRFs) or TBP-like factors (TBPLs) have been discovered in metazoans, TRF1, TBPL1, and TBPL2. TBP is autoregulated, and once bound to DNA, repressors such as Mot1 induce TBP to dissociate, while other factors such as NC2 and the NOT complex convert the active TBP/DNA complex into inactive, negatively regulating TBP. TFIIA antagonizes the TBP repressors but may be effective only in conjunction with the RNA polymerase II holoenzyme recruitment to the promoter by promoter-bound activators. TRF1 has been discovered inDrosophila melanogasterandAnophelesbut found absent in vertebrates and yeast. TBPL1 cannot bind to the TATA-box; instead, TBPL1 prefers binding to TATA-less promoters. However, TBPL1 shows a stronger association with TFIIA than TBP. The TCT core promoter element is present in most ribosomal protein genes inDrosophilaand humans, and TBPL1 is required for the transcription of these genes. TBP directly participates in the DNA repair mechanism, and TBPL1 mediates cell cycle arrest and apoptosis. TBPL2 is closely related to its TBP paralog, showing 95% sequence similarity with the TBP core domain. Like TBP, TBPL2 also binds to the TATA-box and shows interactions with TFIIA, TFIIB, and other basal transcription factors. Despite these advances, much remains to be explored in this family of transcription factors.
Collapse
|
4
|
Alsafwani RS, Nasser KK, Shinawi T, Banaganapalli B, ElSokary HA, Zaher ZF, Shaik NA, Abdelmohsen G, Al-Aama JY, Shapiro AJ, O Al-Radi O, Elango R, Alahmadi T. Novel MYO1D Missense Variant Identified Through Whole Exome Sequencing and Computational Biology Analysis Expands the Spectrum of Causal Genes of Laterality Defects. Front Med (Lausanne) 2021; 8:724826. [PMID: 34589502 PMCID: PMC8473696 DOI: 10.3389/fmed.2021.724826] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 08/10/2021] [Indexed: 11/13/2022] Open
Abstract
Laterality defects (LDs) or asymmetrically positioned organs are a group of rare developmental disorders caused by environmental and/or genetic factors. However, the exact molecular pathophysiology of LD is not yet fully characterised. In this context, studying Arab population presents an ideal opportunity to discover the novel molecular basis of diseases owing to the high rate of consanguinity and genetic disorders. Therefore, in the present study, we studied the molecular basis of LD in Arab patients, using next-generation sequencing method. We discovered an extremely rare novel missense variant in MYO1D gene (Pro765Ser) presenting with visceral heterotaxy and left isomerism with polysplenia syndrome. The proband in this index family has inherited this homozygous variant from her heterozygous parents following the autosomal recessive pattern. This is the first report to show MYO1D genetic variant causing left-right axis defects in humans, besides previous known evidence from zebrafish, frog and Drosophila models. Moreover, our multilevel bioinformatics-based structural (protein variant structural modelling, divergence, and stability) analysis has suggested that Ser765 causes minor structural drifts and stability changes, potentially affecting the biophysical and functional properties of MYO1D protein like calmodulin binding and microfilament motor activities. Functional bioinformatics analysis has shown that MYO1D is ubiquitously expressed across several human tissues and is reported to induce severe phenotypes in knockout mouse models. In conclusion, our findings show the expanded genetic spectrum of LD, which could potentially pave way for the novel drug target identification and development of personalised medicine for high-risk families.
Collapse
Affiliation(s)
- Rabab Said Alsafwani
- Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Khalidah K Nasser
- Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia.,Princess Al-Jawhara Center of Excellence in Research of Hereditary Disorders, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Thoraia Shinawi
- Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Babajan Banaganapalli
- Princess Al-Jawhara Center of Excellence in Research of Hereditary Disorders, King Abdulaziz University, Jeddah, Saudi Arabia.,Department of Genetic Medicine, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Hanan Abdelhalim ElSokary
- Princess Al-Jawhara Center of Excellence in Research of Hereditary Disorders, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Zhaher F Zaher
- Department of Pediatrics, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia.,Pediatric Cardiac Center of Excellence, King Abdulaziz University Hospital, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Noor Ahmad Shaik
- Princess Al-Jawhara Center of Excellence in Research of Hereditary Disorders, King Abdulaziz University, Jeddah, Saudi Arabia.,Department of Genetic Medicine, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia.,Department of Genetics, Al Borg Medical Laboratories, Jeddah, Saudi Arabia
| | - Gaser Abdelmohsen
- Department of Pediatrics, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia.,Pediatric Cardiology Division, Department of Pediatrics, Cairo University, Kasr Al Ainy Faculty of Medicine, Cairo, Egypt
| | - Jumana Yousuf Al-Aama
- Princess Al-Jawhara Center of Excellence in Research of Hereditary Disorders, King Abdulaziz University, Jeddah, Saudi Arabia.,Department of Genetic Medicine, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Adam J Shapiro
- Division of Pediatric Respiratory Medicine, McGill University Health Centre Research Institute, Montreal Children's Hospital, Montreal, QC, Canada
| | - Osman O Al-Radi
- Department of Surgery Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Ramu Elango
- Princess Al-Jawhara Center of Excellence in Research of Hereditary Disorders, King Abdulaziz University, Jeddah, Saudi Arabia.,Department of Genetic Medicine, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Turki Alahmadi
- Department of Pediatrics, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia.,Pediatric Department, Faculty of Medicine in Rabigh, King Abdulaziz University, Jeddah, Saudi Arabia
| |
Collapse
|
5
|
Cui G, Dong Q, Duan J, Zhang C, Liu X, He Q. NC2 complex is a key factor for the activation of catalase-3 transcription by regulating H2A.Z deposition. Nucleic Acids Res 2020; 48:8332-8348. [PMID: 32633757 PMCID: PMC7470962 DOI: 10.1093/nar/gkaa552] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Revised: 06/05/2020] [Accepted: 06/19/2020] [Indexed: 12/16/2022] Open
Abstract
Negative cofactor 2 (NC2), including two subunits NC2α and NC2β, is a conserved positive/negative regulator of class II gene transcription in eukaryotes. It is known that NC2 functions by regulating the assembly of the transcription preinitiation complex. However, the exact role of NC2 in transcriptional regulation is still unclear. Here, we reveal that, in Neurospora crassa, NC2 activates catalase-3 (cat-3) gene transcription in the form of heterodimer mediated by histone fold (HF) domains of two subunits. Deletion of HF domain in either of two subunits disrupts the NC2α–NC2β interaction and the binding of intact NC2 heterodimer to cat-3 locus. Loss of NC2 dramatically increases histone variant H2A.Z deposition at cat-3 locus. Further studies show that NC2 recruits chromatin remodeling complex INO80C to remove H2A.Z from the nucleosomes around cat-3 locus, resulting in transcriptional activation of cat-3. Besides HF domains of two subunits, interestingly, C-terminal repression domain of NC2β is required not only for NC2 binding to cat-3 locus, but also for the recruitment of INO80C to cat-3 locus and removal of H2A.Z from the nucleosomes. Collectively, our findings reveal a novel mechanism of NC2 in transcription activation through recruiting INO80C to remove H2A.Z from special H2A.Z-containing nucleosomes.
Collapse
Affiliation(s)
- Guofei Cui
- State Key Laboratory of Agrobiotechnology and MOA Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Qing Dong
- State Key Laboratory of Agrobiotechnology and MOA Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Jiabin Duan
- State Key Laboratory of Agrobiotechnology and MOA Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Chengcheng Zhang
- State Key Laboratory of Agrobiotechnology and MOA Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Xiao Liu
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.,College of Life Sciences, University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Qun He
- State Key Laboratory of Agrobiotechnology and MOA Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| |
Collapse
|
6
|
HAMADA H. Molecular and cellular basis of left-right asymmetry in vertebrates. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2020; 96:273-296. [PMID: 32788551 PMCID: PMC7443379 DOI: 10.2183/pjab.96.021] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Although the human body appears superficially symmetrical with regard to the left-right (L-R) axis, most visceral organs are asymmetric in terms of their size, shape, or position. Such morphological asymmetries of visceral organs, which are essential for their proper function, are under the control of a genetic pathway that operates in the developing embryo. In many vertebrates including mammals, the breaking of L-R symmetry occurs at a structure known as the L-R organizer (LRO) located at the midline of the developing embryo. This symmetry breaking is followed by transfer of an active form of the signaling molecule Nodal from the LRO to the lateral plate mesoderm (LPM) on the left side, which results in asymmetric expression of Nodal (a left-side determinant) in the left LPM. Finally, L-R asymmetric morphogenesis of visceral organs is induced by Nodal-Pitx2 signaling. This review will describe our current understanding of the mechanisms that underlie the generation of L-R asymmetry in vertebrates, with a focus on mice.
Collapse
Affiliation(s)
- Hiroshi HAMADA
- RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo, Japan
- Correspondence should be addressed: H. Hamada, RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan (e-mail: )
| |
Collapse
|
7
|
Osório L, Wu X, Wang L, Jiang Z, Neideck C, Sheng G, Zhou Z. ISM1 regulates NODAL signaling and asymmetric organ morphogenesis during development. J Cell Biol 2019; 218:2388-2402. [PMID: 31171630 PMCID: PMC6605798 DOI: 10.1083/jcb.201801081] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 03/24/2019] [Accepted: 05/06/2019] [Indexed: 12/14/2022] Open
Abstract
Isthmin1 (ISM1) was originally identified as a fibroblast group factor expressed in Xenopus laevis embryonic brain, but its biological functions remain unclear. The spatiotemporal distribution of ISM1, with high expression in the anterior primitive streak of the chick embryo and the anterior mesendoderm of the mouse embryo, suggested that ISM1 may regulate signaling by the NODAL subfamily of TGB-β cytokines that control embryo patterning. We report that ISM1 is an inhibitor of NODAL signaling. ISM1 has little effect on TGF-β1, ACTIVIN-A, or BMP4 signaling but specifically inhibits NODAL-induced phosphorylation of SMAD2. In line with this observation, ectopic ISM1 causes defective left-right asymmetry and abnormal heart positioning in chick embryos. Mechanistically, ISM1 interacts with NODAL ligand and type I receptor ACVR1B through its AMOP domain, which compromises the NODAL-ACVR1B interaction and down-regulates phosphorylation of SMAD2. Therefore, we identify ISM1 as an extracellular antagonist of NODAL and reveal a negative regulatory mechanism that provides greater plasticity for the fine-tuning of NODAL signaling.
Collapse
Affiliation(s)
- Liliana Osório
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong.,Shenzhen Institute of Innovation and Research, The University of Hong Kong, Nanshan, Shenzhen, China
| | - Xuewei Wu
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong.,Shenzhen Institute of Innovation and Research, The University of Hong Kong, Nanshan, Shenzhen, China
| | - Linsheng Wang
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong.,Shenzhen Institute of Innovation and Research, The University of Hong Kong, Nanshan, Shenzhen, China
| | - Zhixin Jiang
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong.,Shenzhen Institute of Innovation and Research, The University of Hong Kong, Nanshan, Shenzhen, China
| | - Carlos Neideck
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong.,Shenzhen Institute of Innovation and Research, The University of Hong Kong, Nanshan, Shenzhen, China
| | - Guojun Sheng
- International Research Center for Medical Sciences, Kumamoto University, Kumamoto, Japan.,RIKEN Center for Developmental Biology, Kobe, Japan
| | - Zhongjun Zhou
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong .,Shenzhen Institute of Innovation and Research, The University of Hong Kong, Nanshan, Shenzhen, China
| |
Collapse
|
8
|
Zarrabi N, Schluesche P, Meisterernst M, Börsch M, Lamb DC. Analyzing the Dynamics of Single TBP-DNA-NC2 Complexes Using Hidden Markov Models. Biophys J 2018; 115:2310-2326. [PMID: 30527334 DOI: 10.1016/j.bpj.2018.11.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 11/12/2018] [Accepted: 11/12/2018] [Indexed: 10/27/2022] Open
Abstract
Single-pair Förster resonance energy transfer (spFRET) has become an important tool for investigating conformational dynamics in biological systems. To extract dynamic information from the spFRET traces measured with total internal reflection fluorescence microscopy, we extended the hidden Markov model (HMM) approach. In our extended HMM analysis, we incorporated the photon-shot noise from camera-based systems into the HMM. Thus, the variance in Förster resonance energy transfer (FRET) efficiency of the various states, which is typically a fitted parameter, is explicitly included in the analysis estimated from the number of detected photons. It is also possible to include an additional broadening of the FRET state, which would then only reflect the inherent flexibility of the dynamic biological systems. This approach is useful when comparing the dynamics of individual molecules for which the total intensities vary significantly. We used spFRET with the extended HMM analysis to investigate the dynamics of TATA-box-binding protein (TBP) on promoter DNA in the presence of negative cofactor 2 (NC2). We compared the dynamics of two promoters as well as DNAs of different length and labeling location. For the adenovirus major late promoter, four FRET states were observed; three states correspond to different conformations of the DNA in the TBP-DNA-NC2 complex and a four-state model in which the complex has shifted along the DNA. The HMM analysis revealed that the states are connected via a linear, four-well model. For the H2B promoter, more complex dynamics were observed. By clustering the FRET states detected with the HMM analysis, we could compare the general dynamics observed for the two promoter sequences. We observed that the dynamics from a stretched DNA conformation to a bent conformation for the two promoters were similar, whereas the bent conformation of the TBP-DNA-NC2 complex for the H2B promoter is approximately three times more stable than for the adenovirus major late promoter.
Collapse
Affiliation(s)
- Nawid Zarrabi
- Physikalisches Institut, University of Stuttgart, Stuttgart, Baden-Württemberg, Germany; Single-Molecule Microscopy Group, Jena University Hospital, Jena, Thuringia, Germany
| | - Peter Schluesche
- Department Chemie, Center for Nano Science, Center for Integrated Protein Science, and Nanosystems Initiative München, Ludwig-Maximilians-Universität Munich, Munich, Bavaria, Germany
| | - Michael Meisterernst
- GSF-National Research Center for Environment and Health, Gene Expression, Munich, Bavaria, Germany; Institute of Molecular Tumor Biology, Faculty of Medicine, University of Muenster, Muenster, North Rhine-Westphalia, Germany
| | - Michael Börsch
- Physikalisches Institut, University of Stuttgart, Stuttgart, Baden-Württemberg, Germany; Single-Molecule Microscopy Group, Jena University Hospital, Jena, Thuringia, Germany
| | - Don C Lamb
- Department Chemie, Center for Nano Science, Center for Integrated Protein Science, and Nanosystems Initiative München, Ludwig-Maximilians-Universität Munich, Munich, Bavaria, Germany.
| |
Collapse
|
9
|
A mathematical model of the biochemical network underlying left-right asymmetry establishment in mammals. Biosystems 2018; 173:281-297. [PMID: 30292532 DOI: 10.1016/j.biosystems.2018.10.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2018] [Revised: 09/28/2018] [Accepted: 10/02/2018] [Indexed: 11/22/2022]
Abstract
The expression of the TGF-β protein Nodal on the left side of vertebrate embryos is a determining event in the development of internal-organ asymmetry. We present a mathematical model for the control of the expression of Nodal and its antagonist Lefty consisting entirely of realistic elementary reactions. We analyze the model in the absence of Lefty and find a wide range of parameters over which bistability (two stable steady states) is observed, with one stable steady state a low-Nodal state corresponding to the right-hand developmental fate, and the other a high-Nodal state corresponding to the left. We find that bistability requires a transcription factor containing two molecules of phosphorylated Smad2. A numerical survey of the full model, including Lefty, shows the effects of Lefty on the potential for bistability, and on the conditions that lead to the system reaching one or the other steady state.
Collapse
|
10
|
Wei S, Wang Q. Molecular regulation of Nodal signaling during mesendoderm formation. Acta Biochim Biophys Sin (Shanghai) 2018; 50:74-81. [PMID: 29206913 DOI: 10.1093/abbs/gmx128] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 11/09/2017] [Indexed: 01/17/2023] Open
Abstract
One of the most important events during vertebrate embryogenesis is the formation or specification of the three germ layers, endoderm, mesoderm, and ectoderm. After a series of rapid cleavages, embryos form the mesendoderm and ectoderm during late blastulation and early gastrulation. The mesendoderm then further differentiates into the mesoderm and endoderm. Nodal, a member of the transforming growth factor β (TGF-β) superfamily, plays a pivotal role in mesendoderm formation by regulating the expression of a number of critical transcription factors, including Mix-like, GATA, Sox, and Fox. Because the Nodal signal transduction pathway is well-characterized, increasing effort has been made to delineate the spatiotemporal modulation of Nodal signaling during embryonic development. In this review, we summarize the recent progress delineating molecular regulation of Nodal signal intensity and duration during mesendoderm formation.
Collapse
Affiliation(s)
- Shi Wei
- The State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-Sen University Cancer Center, Guangzhou 510060, China
| | - Qiang Wang
- State Key Laboratory of Membrane Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Zoology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100101, China
| |
Collapse
|
11
|
Bhargava S, Cox B, Polydorou C, Gresakova V, Korinek V, Strnad H, Sedlacek R, Epp TA, Chawengsaksophak K. The epigenetic modifier Fam208a is required to maintain epiblast cell fitness. Sci Rep 2017; 7:9322. [PMID: 28839193 PMCID: PMC5570896 DOI: 10.1038/s41598-017-09490-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 07/26/2017] [Indexed: 12/12/2022] Open
Abstract
Gastrulation initiates with the formation of the primitive streak, during which, cells of the epiblast delaminate to form the mesoderm and definitive endoderm. At this stage, the pluripotent cell population of the epiblast undergoes very rapid proliferation and extensive epigenetic programming. Here we show that Fam208a, a new epigenetic modifier, is essential for early post-implantation development. We show that Fam208a mutation leads to impaired primitive streak elongation and delayed epithelial-to-mesenchymal transition. Fam208a mutant epiblasts had increased expression of p53 pathway genes as well as several pluripotency-associated long non-coding RNAs. Fam208a mutants exhibited an increase in p53-driven apoptosis and complete removal of p53 could partially rescue their gastrulation block. This data demonstrates a new in vivo function of Fam208a in maintaining epiblast fitness, establishing it as an important factor at the onset of gastrulation when cells are exiting pluripotency.
Collapse
Affiliation(s)
- Shohag Bhargava
- Laboratory of Transgenic Models of Diseases, Division, BIOCEV, Institute of Molecular Genetics of the CAS, v.v.i., Vestec, Czech Republic.,Faculty of Science, Charles University, Prague, Czech Republic
| | - Brian Cox
- Department of Physiology, Faculty of Medicine, University of Toronto, Ontario, Canada
| | - Christiana Polydorou
- Laboratory of Transgenic Models of Diseases, Division, BIOCEV, Institute of Molecular Genetics of the CAS, v.v.i., Vestec, Czech Republic
| | - Veronika Gresakova
- Laboratory of Transgenic Models of Diseases, Division, BIOCEV, Institute of Molecular Genetics of the CAS, v.v.i., Vestec, Czech Republic
| | - Vladimir Korinek
- Laboratory of Cell and Developmental Biology, Institute of Molecular Genetics of the CAS, v.v.i., Krc, Czech Republic
| | - Hynek Strnad
- Laboratory of Genomics and Bioinformatics, Institute of Molecular Genetics of the CAS, v.v.i., Krc, Czech Republic
| | - Radislav Sedlacek
- Laboratory of Transgenic Models of Diseases, Division, BIOCEV, Institute of Molecular Genetics of the CAS, v.v.i., Vestec, Czech Republic.,Czech Centre for Phenogenomics, Division BIOCEV, Institute of Molecular Genetics of the CAS, v.v.i., Vestec, Czech Republic
| | - Trevor Allan Epp
- Laboratory of Transgenic Models of Diseases, Division, BIOCEV, Institute of Molecular Genetics of the CAS, v.v.i., Vestec, Czech Republic. .,Czech Centre for Phenogenomics, Division BIOCEV, Institute of Molecular Genetics of the CAS, v.v.i., Vestec, Czech Republic.
| | - Kallayanee Chawengsaksophak
- Laboratory of Transgenic Models of Diseases, Division, BIOCEV, Institute of Molecular Genetics of the CAS, v.v.i., Vestec, Czech Republic. .,Czech Centre for Phenogenomics, Division BIOCEV, Institute of Molecular Genetics of the CAS, v.v.i., Vestec, Czech Republic.
| |
Collapse
|
12
|
Cunningham TJ, Colas A, Duester G. Early molecular events during retinoic acid induced differentiation of neuromesodermal progenitors. Biol Open 2016; 5:1821-1833. [PMID: 27793834 PMCID: PMC5200905 DOI: 10.1242/bio.020891] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Bipotent neuromesodermal progenitors (NMPs) residing in the caudal epiblast drive coordinated body axis extension by generating both posterior neuroectoderm and presomitic mesoderm. Retinoic acid (RA) is required for body axis extension, however the early molecular response to RA signaling is poorly defined, as is its relationship to NMP biology. As endogenous RA is first seen near the time when NMPs appear, we used WNT/FGF agonists to differentiate embryonic stem cells to NMPs which were then treated with a short 2-h pulse of 25 nM RA or 1 µM RA followed by RNA-seq transcriptome analysis. Differential expression analysis of this dataset indicated that treatment with 25 nM RA, but not 1 µM RA, provided physiologically relevant findings. The 25 nM RA dataset yielded a cohort of previously known caudal RA target genes including Fgf8 (repressed) and Sox2 (activated), plus novel early RA signaling targets with nearby conserved RA response elements. Importantly, validation of top-ranked genes in vivo using RA-deficient Raldh2-/- embryos identified novel examples of RA activation (Nkx1-2, Zfp503, Zfp703, Gbx2, Fgf15, Nt5e) or RA repression (Id1) of genes expressed in the NMP niche or progeny. These findings provide evidence for early instructive and permissive roles of RA in controlling differentiation of NMPs to neural and mesodermal lineages.
Collapse
Affiliation(s)
- Thomas J Cunningham
- Development, Aging, and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Alexandre Colas
- Development, Aging, and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Gregg Duester
- Development, Aging, and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| |
Collapse
|
13
|
Sampath K, Robertson EJ. Keeping a lid on nodal: transcriptional and translational repression of nodal signalling. Open Biol 2016; 6:150200. [PMID: 26791244 PMCID: PMC4736825 DOI: 10.1098/rsob.150200] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Nodal is an evolutionarily conserved member of the transforming growth factor-β (TGF-β) superfamily of secreted signalling factors. Nodal factors are known to play key roles in embryonic development and asymmetry in a variety of organisms ranging from hydra and sea urchins to fish, mice and humans. In addition to embryonic patterning, Nodal signalling is required for maintenance of human embryonic stem cell pluripotency and mis-regulated Nodal signalling has been found associated with tumour metastases. Therefore, precise and timely regulation of this pathway is essential. Here, we discuss recent evidence from sea urchins, frogs, fish, mice and humans that show a role for transcriptional and translational repression of Nodal signalling during early development.
Collapse
Affiliation(s)
- Karuna Sampath
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry CV4 7AJ, UK
| | | |
Collapse
|
14
|
Zic2mutation causes holoprosencephaly via disruption of NODAL signalling. Hum Mol Genet 2016; 25:3946-3959. [DOI: 10.1093/hmg/ddw235] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 06/30/2016] [Accepted: 07/11/2016] [Indexed: 12/14/2022] Open
|
15
|
Jin JZ, Zhu Y, Warner D, Ding J. Analysis of extraembryonic mesodermal structure formation in the absence of morphological primitive streak. Dev Growth Differ 2016; 58:522-9. [PMID: 27273137 DOI: 10.1111/dgd.12294] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 04/15/2016] [Accepted: 04/17/2016] [Indexed: 11/30/2022]
Abstract
During mouse gastrulation, the primitive streak is formed on the posterior side of the embryo. Cells migrate out of the primitive streak to form the future mesoderm and endoderm. Fate mapping studies revealed a group of cell migrate through the proximal end of the primitive streak and give rise to the extraembryonic mesoderm tissues such as the yolk sac blood islands and allantois. However, it is not clear whether the formation of a morphological primitive streak is required for the development of these extraembryonic mesodermal tissues. Loss of the Cripto gene in mice dramatically reduces, but does not completely abolish, Nodal activity leading to the absence of a morphological primitive streak. However, embryonic erythrocytes are still formed and assembled into the blood islands. In addition, Cripto mutant embryos form allantoic buds. However, Drap1 mutant embryos have excessive Nodal activity in the epiblast cells before gastrulation and form an expanded primitive streak, but no yolk sac blood islands or allantoic bud formation. Lefty2 embryos also have elevated levels of Nodal activity in the primitive streak during gastrulation, and undergo normal blood island and allantois formation. We therefore speculate that low level of Nodal activity disrupts the formation of morphological primitive streak on the posterior side, but still allows the formation of primitive streak cells on the proximal side, which give rise to the extraembryonic mesodermal tissues formation. Excessive Nodal activity in the epiblast at pre-gastrulation stage, but not in the primitive streak cells during gastrulation, disrupts extraembryonic mesoderm development.
Collapse
Affiliation(s)
- Jiu-Zhen Jin
- Department of Molecular, Cellular & Craniofacial Biology and Birth Defects Center, University of Louisville, Louisville, Kentucky, USA
| | - Yuanqi Zhu
- Department of Molecular, Cellular & Craniofacial Biology and Birth Defects Center, University of Louisville, Louisville, Kentucky, USA
| | - Dennis Warner
- Department of Molecular, Cellular & Craniofacial Biology and Birth Defects Center, University of Louisville, Louisville, Kentucky, USA
| | - Jixiang Ding
- Department of Molecular, Cellular & Craniofacial Biology and Birth Defects Center, University of Louisville, Louisville, Kentucky, USA
| |
Collapse
|
16
|
Reid CD, Steiner AB, Yaklichkin S, Lu Q, Wang S, Hennessy M, Kessler DS. FoxH1 mediates a Grg4 and Smad2 dependent transcriptional switch in Nodal signaling during Xenopus mesoderm development. Dev Biol 2016; 414:34-44. [PMID: 27085753 DOI: 10.1016/j.ydbio.2016.04.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 03/28/2016] [Accepted: 04/06/2016] [Indexed: 02/07/2023]
Abstract
In the vertebrate blastula and gastrula the Nodal pathway is essential for formation of the primary germ layers and the organizer. Nodal autoregulatory feedback potentiates signaling activity, but mechanisms limiting embryonic Nodal ligand transcription are poorly understood. Here we describe a transcriptional switch mechanism mediated by FoxH1, the principle effector of Nodal autoregulation. FoxH1 contains a conserved engrailed homology (EH1) motif that mediates direct binding of groucho-related gene 4 (Grg4), a Groucho family corepressor. Nodal-dependent gene expression is suppressed by FoxH1, but enhanced by a FoxH1 EH1 mutant, indicating that the EH1 motif is necessary for repression. Grg4 blocks Nodal-induced mesodermal gene expression and Nodal autoregulation, suggesting that Grg4 limits Nodal pathway activity. Conversely, blocking Grg4 function in the ectoderm results in ectopic expression of Nodal target genes. FoxH1 and Grg4 occupy the Xnr1 enhancer, and Grg4 occupancy is dependent on the FoxH1 EH1 motif. Grg4 occupancy at the Xnr1 enhancer significantly decreases with Nodal activation or Smad2 overexpression, while FoxH1 occupancy is unaffected. These results suggest that Nodal-activated Smad2 physically displaces Grg4 from FoxH1, an essential feature of the transcriptional switch mechanism. In support of this model, when FoxH1 is unable to bind Smad2, Grg4 occupancy is maintained at the Xnr1 enhancer, even in the presence of Nodal signaling. Our findings reveal that FoxH1 mediates both activation and repression of Nodal gene expression. We propose that this transcriptional switch is essential to delimit Nodal pathway activity in vertebrate germ layer formation.
Collapse
Affiliation(s)
- Christine D Reid
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine Smilow Center for Translational Research, Room 9-104, 3400 Civic Center Blvd Philadelphia, PA 19104, USA
| | - Aaron B Steiner
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine Smilow Center for Translational Research, Room 9-104, 3400 Civic Center Blvd Philadelphia, PA 19104, USA
| | - Sergey Yaklichkin
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine Smilow Center for Translational Research, Room 9-104, 3400 Civic Center Blvd Philadelphia, PA 19104, USA
| | - Qun Lu
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine Smilow Center for Translational Research, Room 9-104, 3400 Civic Center Blvd Philadelphia, PA 19104, USA
| | - Shouwen Wang
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine Smilow Center for Translational Research, Room 9-104, 3400 Civic Center Blvd Philadelphia, PA 19104, USA
| | - Morgan Hennessy
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine Smilow Center for Translational Research, Room 9-104, 3400 Civic Center Blvd Philadelphia, PA 19104, USA
| | - Daniel S Kessler
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine Smilow Center for Translational Research, Room 9-104, 3400 Civic Center Blvd Philadelphia, PA 19104, USA
| |
Collapse
|
17
|
Talukdar HA, Foroughi Asl H, Jain RK, Ermel R, Ruusalepp A, Franzén O, Kidd BA, Readhead B, Giannarelli C, Kovacic JC, Ivert T, Dudley JT, Civelek M, Lusis AJ, Schadt EE, Skogsberg J, Michoel T, Björkegren JLM. Cross-Tissue Regulatory Gene Networks in Coronary Artery Disease. Cell Syst 2016; 2:196-208. [PMID: 27135365 PMCID: PMC4855300 DOI: 10.1016/j.cels.2016.02.002] [Citation(s) in RCA: 96] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 12/02/2015] [Accepted: 01/30/2016] [Indexed: 01/23/2023]
Abstract
Inferring molecular networks can reveal how genetic perturbations interact with environmental factors to cause common complex diseases. We analyzed genetic and gene expression data from seven tissues relevant to coronary artery disease (CAD) and identified regulatory gene networks (RGNs) and their key drivers. By integrating data from genome-wide association studies, we identified 30 CAD-causal RGNs interconnected in vascular and metabolic tissues, and we validated them with corresponding data from the Hybrid Mouse Diversity Panel. As proof of concept, by targeting the key drivers AIP, DRAP1, POLR2I, and PQBP1 in a cross-species-validated, arterial-wall RGN involving RNA-processing genes, we re-identified this RGN in THP-1 foam cells and independent data from CAD macrophages and carotid lesions. This characterization of the molecular landscape in CAD will help better define the regulation of CAD candidate genes identified by genome-wide association studies and is a first step toward achieving the goals of precision medicine.
Collapse
Affiliation(s)
- Husain A Talukdar
- Cardiovascular Genomics Group, Division of Vascular Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Hassan Foroughi Asl
- Cardiovascular Genomics Group, Division of Vascular Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Rajeev K Jain
- Department of Physiology, Institute of Biomedicine and Translation Medicine, University of Tartu, 51014 Tartu, Estonia
| | - Raili Ermel
- Department of Physiology, Institute of Biomedicine and Translation Medicine, University of Tartu, 51014 Tartu, Estonia; Department of Cardiac Surgery, Tartu University Hospital, 51014 Tartu, Estonia
| | - Arno Ruusalepp
- Department of Physiology, Institute of Biomedicine and Translation Medicine, University of Tartu, 51014 Tartu, Estonia; Department of Cardiac Surgery, Tartu University Hospital, 51014 Tartu, Estonia; Clinical Gene Networks AB, 114 44 Stockholm, Sweden
| | - Oscar Franzén
- Clinical Gene Networks AB, 114 44 Stockholm, Sweden; Department of Genetics & Genomic Sciences, Institute of Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Brian A Kidd
- Department of Genetics & Genomic Sciences, Institute of Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Ben Readhead
- Department of Genetics & Genomic Sciences, Institute of Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Chiara Giannarelli
- Department of Genetics & Genomic Sciences, Institute of Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; The Zena and Michael A. Wiener Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Jason C Kovacic
- The Zena and Michael A. Wiener Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Torbjörn Ivert
- Department of Molecular Medicine and Surgery, Karolinska Institutet, 171 77 Stockholm, Sweden; Department of Thoracic Surgery, Karolinska University Hospital, 171 76 Stockholm, Sweden
| | - Joel T Dudley
- Department of Genetics & Genomic Sciences, Institute of Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Mete Civelek
- Departments of Medicine, Cardiology, Human Genetics, Microbiology, Immunology & Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90024, USA
| | - Aldons J Lusis
- Departments of Medicine, Cardiology, Human Genetics, Microbiology, Immunology & Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90024, USA
| | - Eric E Schadt
- Clinical Gene Networks AB, 114 44 Stockholm, Sweden; Department of Genetics & Genomic Sciences, Institute of Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Josefin Skogsberg
- Cardiovascular Genomics Group, Division of Vascular Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Tom Michoel
- Clinical Gene Networks AB, 114 44 Stockholm, Sweden; Division of Genetics and Genomics, The Roslin Institute, University of Edinburgh, Edinburgh EH25 9RG, UK
| | - Johan L M Björkegren
- Cardiovascular Genomics Group, Division of Vascular Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 171 77 Stockholm, Sweden; Department of Physiology, Institute of Biomedicine and Translation Medicine, University of Tartu, 51014 Tartu, Estonia; Clinical Gene Networks AB, 114 44 Stockholm, Sweden; Department of Genetics & Genomic Sciences, Institute of Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Cardiovascular Institute, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
| |
Collapse
|
18
|
Viotti M, Foley AC, Hadjantonakis AK. Gutsy moves in mice: cellular and molecular dynamics of endoderm morphogenesis. Philos Trans R Soc Lond B Biol Sci 2015; 369:rstb.2013.0547. [PMID: 25349455 DOI: 10.1098/rstb.2013.0547] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Despite the importance of the gut and its accessory organs, our understanding of early endoderm development is still incomplete. Traditionally, endoderm has been difficult to study because of its small size and relative fragility. However, recent advances in live cell imaging technologies have dramatically expanded our understanding of this tissue, adding a new appreciation for the complex molecular and morphogenetic processes that mediate gut formation. Several spatially and molecularly distinct subpopulations have been shown to exist within the endoderm before the onset of gastrulation. Here, we review findings that have uncovered complex cell movements within the endodermal layer, before and during gastrulation, leading to the conclusion that cells from primitive endoderm contribute descendants directly to gut.
Collapse
Affiliation(s)
- Manuel Viotti
- Genentech Incorporated, South San Francisco, CA 94080, USA
| | - Ann C Foley
- Department of Bioengineering, Clemson University, Charleston, SC 29425, USA
| | | |
Collapse
|
19
|
Terashima AV, Mudumana SP, Drummond IA. Odd skipped related 1 is a negative feedback regulator of nodal-induced endoderm development. Dev Dyn 2014; 243:1571-80. [PMID: 25233796 DOI: 10.1002/dvdy.24191] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Revised: 09/03/2014] [Accepted: 09/10/2014] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Early embryo patterning is orchestrated by tightly regulated morphogen gradients. The Nodal morphogen patterns the mesendoderm, giving rise to all endoderm and head and trunk mesoderm. High Nodal concentrations favor endoderm differentiation while lower promote mesoderm differentiation. Nodal signaling is controlled by both positive and negative feedback regulation to ensure robust developmental patterning. RESULTS Here we identify odd skipped related 1 (osr1), a zinc finger transcription factor, as a new element in Nodal feedback regulation affecting endoderm development. We show that osr1 expression in zebrafish germ ring mesendoderm requires Nodal signaling; osr1 expression was lost in embryos lacking Nodal signaling. Conversely, osr1 expression was ectopically induced by the activation of Nodal signaling. Furthermore we demonstrate that osr1 responds directly to Nodal signaling. Additionally, osr1 knockdown generated excess endoderm cells marked by sox32 expression while expression of osr1 mRNA was not affected in sox32-deficient embryos. CONCLUSIONS Our findings identify osr1 as a Nodal-induced, negative feedback regulator of Nodal signaling that acts at the earliest stages of endoderm differentiation to limit the number of endoderm progenitors. As such, we propose that osr1 represents a novel network motif controlling the output of Nodal signaling to regulate mesendoderm patterning.
Collapse
|
20
|
Rivera-Pérez JA, Hadjantonakis AK. The Dynamics of Morphogenesis in the Early Mouse Embryo. Cold Spring Harb Perspect Biol 2014; 7:cshperspect.a015867. [PMID: 24968703 DOI: 10.1101/cshperspect.a015867] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
SUMMARYOver the past two decades, our understanding of mouse development from implantation to gastrulation has grown exponentially with an upsurge of genetic, molecular, cellular, and morphogenetic information. New discoveries have exalted the role of extraembryonic tissues in orchestrating embryonic patterning and axial specification. At the same time, the identification of unexpected morphogenetic processes occurring during mouse gastrulation has challenged established dogmas and brought new insights into the mechanisms driving germ layer formation. In this article, we summarize the key findings that have reinvigorated the contemporary view of early postimplantation mammalian development.
Collapse
Affiliation(s)
- Jaime A Rivera-Pérez
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01655
| | - Anna-Katerina Hadjantonakis
- Developmental Biology Program, Sloan-Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, New York 10065
| |
Collapse
|
21
|
Kang N, Won M, Rhee M, Ro H. Siah ubiquitin ligases modulate nodal signaling during zebrafish embryonic development. Mol Cells 2014; 37:389-98. [PMID: 24823357 PMCID: PMC4044310 DOI: 10.14348/molcells.2014.0032] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Revised: 03/27/2014] [Accepted: 03/31/2014] [Indexed: 01/15/2023] Open
Abstract
Siah2 is a zebrafish homologue of mammalian Siah family. Siah acts as an E3 ubiquitin ligase that binds proteins destined for degradation. Extensive homology between siah and Drosophila Siah homologue (sina) suggests their important physiological roles during embryonic development. However, detailed functional studies of Siah in vertebrate development have not been carried out. Here we report that Siah2 specifically augments nodal related gene expression in marginal blastomeres at late blastula through early gastrula stages of zebrafish embryos. Siah2 dependent Nodal signaling augmentation is confirmed by cell-based reporter gene assays using 293T cells and 3TPluciferase reporter plasmid. We also established a molecular hierarchy of Siah as a upstream regulator of FoxH1/Fast1 transcriptional factor in Nodal signaling. Elevated expression of nodal related genes by overexpression of Siah2 was enough to override the inhibitory effects of atv and lft2 on the Nodal signaling. In particular, E3 ubiquitin ligase activity of Siah2 is critical to limit the duration and/or magnitude of Nodal signaling. Additionally, since the embryos injected with Siah morpholinos mimicked the atv overexpression phenotype at least in part, our data support a model in which Siah is involved in mesendoderm patterning via modulating Nodal signaling.
Collapse
Affiliation(s)
- Nami Kang
- Department of Biological Sciences, College of Bioscience and Biotechnology, Chungnam National University, Daejeon 305-764,
Korea
| | - Minho Won
- Program in Genomics of Differentiation, Eunice Kennedy Shiver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland,
USA
| | - Myungchull Rhee
- Department of Biological Sciences, College of Bioscience and Biotechnology, Chungnam National University, Daejeon 305-764,
Korea
| | - Hyunju Ro
- Department of Biological Sciences, College of Bioscience and Biotechnology, Chungnam National University, Daejeon 305-764,
Korea
| |
Collapse
|
22
|
Jin JZ, Ding J. Cripto is required for mesoderm and endoderm cell allocation during mouse gastrulation. Dev Biol 2013; 381:170-8. [PMID: 23747598 DOI: 10.1016/j.ydbio.2013.05.029] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 05/28/2013] [Accepted: 05/29/2013] [Indexed: 10/26/2022]
Abstract
During mouse gastrulation, cells in the primitive streak undergo epithelial-mesenchymal transformation and the resulting mesenchymal cells migrate out laterally to form mesoderm and definitive endoderm across the entire embryonic cylinder. The mechanisms underlying mesoderm and endoderm specification, migration, and allocation are poorly understood. In this study, we focused on the function of mouse Cripto, a member of the EGF-CFC gene family that is highly expressed in the primitive streak and migrating mesoderm cells on embryonic day 6.5. Conditional inactivation of Cripto during gastrulation leads to varied defects in mesoderm and endoderm development. Mutant embryos display accumulation of mesenchymal cells around the shortened primitive streak indicating a functional requirement of Cripto during the formation of mesoderm layer in gastrulation. In addition, some mutant embryos showed poor formation and abnormal allocation of definitive endoderm cells on embryonic day 7.5. Consistently, many mutant embryos that survived to embryonic day 8.5 displayed defects in ventral closure of the gut endoderm causing cardia bifida. Detailed analyses revealed that both the Fgf8-Fgfr1 pathway and p38 MAP kinase activation are partially affected by the loss of Cripto function. These results demonstrate a critical role for Cripto during mouse gastrulation, especially in mesoderm and endoderm formation and allocation.
Collapse
Affiliation(s)
- Jiu-Zhen Jin
- Department of Molecular, Cellular & Craniofacial Biology, University of Louisville School of Dentistry, Louisville, KY 40202, USA
| | | |
Collapse
|
23
|
Abstract
Epithelial-mesenchymal transition (EMT) is a crucial, evolutionarily conserved process that occurs during development and is essential for shaping embryos. Also implicated in cancer, this morphological transition is executed through multiple mechanisms in different contexts, and studies suggest that the molecular programs governing EMT, albeit still enigmatic, are embedded within developmental programs that regulate specification and differentiation. As we review here, knowledge garnered from studies of EMT during gastrulation, neural crest delamination and heart formation have furthered our understanding of tumor progression and metastasis.
Collapse
Affiliation(s)
- Jormay Lim
- Institute of Molecular Cell Biology, ASTAR, 61 Biopolis Drive, Singapore
| | | |
Collapse
|
24
|
Colas AR, McKeithan WL, Cunningham TJ, Bushway PJ, Garmire LX, Duester G, Subramaniam S, Mercola M. Whole-genome microRNA screening identifies let-7 and mir-18 as regulators of germ layer formation during early embryogenesis. Genes Dev 2012; 26:2567-79. [PMID: 23152446 DOI: 10.1101/gad.200758.112] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Tight control over the segregation of endoderm, mesoderm, and ectoderm is essential for normal embryonic development of all species, yet how neighboring embryonic blastomeres can contribute to different germ layers has never been fully explained. We postulated that microRNAs, which fine-tune many biological processes, might modulate the response of embryonic blastomeres to growth factors and other signals that govern germ layer fate. A systematic screen of a whole-genome microRNA library revealed that the let-7 and miR-18 families increase mesoderm at the expense of endoderm in mouse embryonic stem cells. Both families are expressed in ectoderm and mesoderm, but not endoderm, as these tissues become distinct during mouse and frog embryogenesis. Blocking let-7 function in vivo dramatically affected cell fate, diverting presumptive mesoderm and ectoderm into endoderm. siRNA knockdown of computationally predicted targets followed by mutational analyses revealed that let-7 and miR-18 down-regulate Acvr1b and Smad2, respectively, to attenuate Nodal responsiveness and bias blastomeres to ectoderm and mesoderm fates. These findings suggest a crucial role for the let-7 and miR-18 families in germ layer specification and reveal a remarkable conservation of function from amphibians to mammals.
Collapse
|
25
|
Pereira PNG, Dobreva MP, Maas E, Cornelis FM, Moya IM, Umans L, Verfaillie CM, Camus A, de Sousa Lopes SMC, Huylebroeck D, Zwijsen A. Antagonism of Nodal signaling by BMP/Smad5 prevents ectopic primitive streak formation in the mouse amnion. Development 2012; 139:3343-54. [PMID: 22912414 DOI: 10.1242/dev.075465] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The strength and spatiotemporal activity of Nodal signaling is tightly controlled in early implantation mouse embryos, including by autoregulation and feedback loops, and involves secreted and intracellular antagonists. These control mechanisms, which are established at the extra-embryonic/embryonic interfaces, are essential for anterior-posterior patterning of the epiblast and correct positioning of the primitive streak. Formation of an ectopic primitive streak, or streak expansion, has previously been reported in mutants lacking antagonists that target Nodal signaling. Here, we demonstrate that loss-of-function of a major bone morphogenetic protein (BMP) effector, Smad5, results in formation of an ectopic primitive streak-like structure in mutant amnion accompanied by ectopic Nodal expression. This suggests that BMP/Smad5 signaling contributes to negative regulation of Nodal. In cultured cells, we find that BMP-activated Smad5 antagonizes Nodal signaling by interfering with the Nodal-Smad2/4-Foxh1 autoregulatory pathway through the formation of an unusual BMP4-induced Smad complex containing Smad2 and Smad5. Quantitative expression analysis supports that ectopic Nodal expression in the Smad5 mutant amnion is induced by the Nodal autoregulatory loop and a slow positive-feedback loop. The latter involves BMP4 signaling and also induction of ectopic Wnt3. Ectopic activation of these Nodal feedback loops in the Smad5 mutant amnion results in the eventual formation of an ectopic primitive streak-like structure. We conclude that antagonism of Nodal signaling by BMP/Smad5 signaling prevents primitive streak formation in the amnion of normal mouse embryos.
Collapse
Affiliation(s)
- Paulo N G Pereira
- Laboratory of Developmental Signaling of the VIB11 Center for the Biology of Disease, VIB, and Center for Human Genetics, KU Leuven, B-3000 Leuven, Belgium
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
26
|
Trask MC, Tremblay KD, Mager J. Yin-Yang1 is required for epithelial-to-mesenchymal transition and regulation of Nodal signaling during mammalian gastrulation. Dev Biol 2012; 368:273-82. [PMID: 22669107 DOI: 10.1016/j.ydbio.2012.05.031] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Revised: 05/14/2012] [Accepted: 05/22/2012] [Indexed: 12/15/2022]
Abstract
The ubiquitously expressed Polycomb Group protein Yin-Yang1 (YY1) is believed to regulate gene expression through direct binding to DNA elements found in promoters or enhancers of target loci. Additionally, YY1 contains diverse domains that enable a plethora of protein-protein interactions, including association with the Oct4/Sox2 pluripotency complex and Polycomb Group silencing complexes. To elucidate the in vivo role of YY1 during gastrulation, we generated embryos with an epiblast specific deletion of Yy1. Yy1 conditional knockout (cKO) embryos initiate gastrulation, but both primitive streak formation and ingression through the streak is severely impaired. These streak descendants fail to repress E-Cadherin and are unable to undergo an appropriate epithelial to mesenchymal transition (EMT). Intriguingly, overexpression of Nodal and concomitant reduction of Lefty2 are observed in Yy1 cKO embryos, suggesting that YY1 is normally required for proper Nodal regulation during gastrulation. Furthermore, definitive endoderm is specified but fails to properly integrate into the outer layer. Although anterior neuroectoderm is specified, mesoderm production is severely restricted. We show that YY1 directly binds to the Lefty2 locus in E7.5 embryos and that pharmacological inhibition of Nodal signaling partially restores mesoderm production in Yy1 cKO mutant embryos. Our results reveal critical requirements for YY1 during several important developmental processes, including EMT and regulation of Nodal signaling. These results are the first to elucidate the diverse role of YY1 during gastrulation in vivo.
Collapse
Affiliation(s)
- Mary C Trask
- Department of Veterinary and Animal Science, University of Massachusetts, Amherst, 661 North Pleasant Street, Amherst, MA 01003, United States
| | | | | |
Collapse
|
27
|
Choi SC, Han JK. Negative Regulation of Activin Signal Transduction. VITAMINS & HORMONES 2011; 85:79-104. [DOI: 10.1016/b978-0-12-385961-7.00005-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
|
28
|
Forkhead box H1 (FOXH1) sequence variants in ventricular septal defect. Int J Cardiol 2010; 145:83-5. [DOI: 10.1016/j.ijcard.2009.05.030] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2009] [Accepted: 05/11/2009] [Indexed: 12/11/2022]
|
29
|
Abstract
Nodal signals belong to the TGF-beta superfamily and are essential for the induction of mesoderm and endoderm and the determination of the left-right axis. Nodal signals can act as morphogens-they have concentration-dependent effects and can act at a distance from their source of production. Nodal and its feedback inhibitor Lefty form an activator/inhibitor pair that behaves similarly to postulated reaction-diffusion models of tissue patterning. Nodal morphogen activity is also regulated by microRNAs, convertases, TGF-beta signals, coreceptors, and trafficking factors. This article describes how Nodal morphogens pattern embryonic fields and discusses how Nodal morphogen signaling is modulated.
Collapse
|
30
|
Du J, Takeuchi H, Leonhard-Melief C, Shroyer KR, Dlugosz M, Haltiwanger RS, Holdener BC. O-fucosylation of thrombospondin type 1 repeats restricts epithelial to mesenchymal transition (EMT) and maintains epiblast pluripotency during mouse gastrulation. Dev Biol 2010; 346:25-38. [PMID: 20637190 DOI: 10.1016/j.ydbio.2010.07.008] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2010] [Revised: 06/09/2010] [Accepted: 07/07/2010] [Indexed: 10/19/2022]
Abstract
Thrombospondin type 1 repeat (TSR) superfamily members regulate diverse biological activities ranging from cell motility to inhibition of angiogenesis. In this study, we verified that mouse protein O-fucosyltransferase-2 (POFUT2) specifically adds O-fucose to TSRs. Using two Pofut2 gene-trap lines, we demonstrated that O-fucosylation of TSRs was essential for restricting epithelial to mesenchymal transition in the primitive streak, correct patterning of mesoderm, and localization of the definitive endoderm. Although Pofut2 mutant embryos established anterior/posterior polarity, they underwent extensive mesoderm differentiation at the expense of maintaining epiblast pluripotency. Moreover, mesoderm differentiation was biased towards the vascular endothelial cell lineage. Localization of Foxa2 and Cer1 expressing cells within the interior of Pofut2 mutant embryos suggested that POFUT2 activity was also required for the displacement of the primitive endoderm by definitive endoderm. Notably, Nodal, BMP4, Fgf8, and Wnt3 expression were markedly elevated and expanded in Pofut2 mutants, providing evidence that O-fucose modification of TSRs was essential for modulation of growth factor signaling during gastrulation. The ability of Pofut2 mutant embryos to form teratomas comprised of tissues from all three germ layer origins suggested that defects in Pofut2 mutant embryos resulted from abnormalities in the extracellular environment. This prediction is consistent with the observation that POFUT2 targets are constitutive components of the extracellular matrix (ECM) or associate with the ECM. For this reason, the Pofut2 mutants represent a valuable tool for studying the role of O-fucosylation in ECM synthesis and remodeling, and will be a valuable model to study how post-translational modification of ECM components regulates the formation of tissue boundaries, cell movements, and signaling.
Collapse
Affiliation(s)
- Jianguang Du
- Department of Biochemistry and Cell Biology, Institute for Cell and Developmental Biology, Center for Developmental Genetics, Stony Brook University, Stony Brook, NY 11794-5215, USA
| | | | | | | | | | | | | |
Collapse
|
31
|
Agca C, Klein WH, Venuti JM. Reduced O2and elevated ROS in sea urchin embryos leads to defects in ectoderm differentiation. Dev Dyn 2009; 238:1777-87. [DOI: 10.1002/dvdy.22001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
|
32
|
Abstract
Holoprosencephaly (HPE), the most common human forebrain malformation, occurs in 1 in 250 fetuses and 1 in 16,000 live births. HPE is etiologically heterogeneous, and its pathology is variable. Several mouse models of HPE have been generated, and some of the molecular causes of different forms of HPE and the mechanisms underlying its variable pathology have been revealed by these models. Herein, we summarize the current knowledge on the genetic alterations that cause HPE and discuss some important questions about this disease that remain to be answered.
Collapse
Affiliation(s)
- Xin Geng
- Department of Genetics and Tumor Cell Biology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA
| | | |
Collapse
|
33
|
Respecification of ectoderm and altered Nodal expression in sea urchin embryos after cobalt and nickel treatment. Mech Dev 2009; 126:430-42. [DOI: 10.1016/j.mod.2009.01.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2008] [Revised: 01/18/2009] [Accepted: 01/20/2009] [Indexed: 01/29/2023]
|
34
|
Kahle J, Piaia E, Neimanis S, Meisterernst M, Doenecke D. Regulation of nuclear import and export of negative cofactor 2. J Biol Chem 2009; 284:9382-93. [PMID: 19204005 PMCID: PMC2666590 DOI: 10.1074/jbc.m805694200] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2008] [Revised: 01/20/2009] [Indexed: 12/21/2022] Open
Abstract
The negative cofactor 2 (NC2) is a protein complex composed of two subunits, NC2alpha and NC2beta, and plays a key role in transcription regulation. Here we investigate whether each subunit contains a nuclear localization signal (NLS) that permits individual crossing of the nuclear membrane or whether nuclear import of NC2alpha and NC2beta depends on heterodimerization. Our results from in vitro binding studies and transfection experiments in cultured cells show that each subunit contains a classical NLS (cNLS) that is recognized by the importin alpha/beta heterodimer. Regardless of the individual cNLSs the two NC2 subunits are translocated as a preassembled complex as co-transfection experiments with wild-type and cNLS-deficient NC2 subunits demonstrate. Ran-dependent binding of the nuclear export receptor Crm1/exportin 1 confirmed the presence of a leucine-rich nuclear export signal (NES) in NC2beta. In contrast, NC2alpha does not exhibit a NES. Our results from interspecies heterokaryon assays suggest that heterodimerization with NC2alpha masks the NES in NC2beta, which prevents nuclear export of the NC2 complex. A mutation in either one of the two cNLSs decreases the extent of importin alpha/beta-mediated nuclear import of the NC2 complex. In addition, the NC2 complex can enter the nucleus via a second pathway, facilitated by importin 13. Because importin 13 binds exclusively to the NC2 complex but not to the individual subunits this alternative import pathway depends on sequence elements distributed among the two subunits.
Collapse
Affiliation(s)
- Joerg Kahle
- Institute of Biochemistry and Molecular Cell Biology, Department of Molecular Biology, Georg-August-University, Humboldtalle 23, 37073 Göttingen, Germany
| | | | | | | | | |
Collapse
|
35
|
Abstract
Trim33 (Tif1gamma, ectodermin, moonshine), a member of the TIF1 family of transcriptional coactivators and corepressors, is a large nuclear protein that contains an N-terminal tripartite (Trim) domain composed of a RING domain, two B-box domains, and a coiled coil domain. It has been suggested that Trim33 (Ectodermin) mediates ectodermal induction in the Xenopus by functioning as a Smad4 ubiquitin ligase, while in the zebrafish Trim33 (moonshine) has been reported to act as a R-Smad binding protein in induction of erythroid differentiation. Since the developmental role of Trim33 in mammals is currently unknown, we generated mice carrying the conditional Trim33 (Trim33(FX)) allele by flanking exons 2-4 encoding most of the functionally critical N-terminal tripartite domain by loxP sites. We confirmed the null genotype by using the EIIa-Cre transgenic approach to create mice that lack exons 2-4. Embryos deficient in Trim33 die during early somitogenesis, demonstrating that Trim33 plays an important nonredundant role in mammalian embryonic development.
Collapse
Affiliation(s)
- Jieun Kim
- Developmental Biology Program, The Saban Research Institute of Childrens Hospital Los Angeles, Department of Pathology, The Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | | |
Collapse
|
36
|
NC2 mobilizes TBP on core promoter TATA boxes. Nat Struct Mol Biol 2007; 14:1196-201. [PMID: 17994103 DOI: 10.1038/nsmb1328] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2007] [Accepted: 10/02/2007] [Indexed: 11/08/2022]
Abstract
The general transcription factors (GTFs) of eukaryotic RNA polymerase II, in a process facilitated by regulatory and accessory factors, target promoters through synergistic interactions with core elements. The specific binding of the TATA box-binding protein (TBP) to the TATA box has led to the assumption that GTFs recognize promoters directly, producing a preinitiation complex at a defined position. Using biochemical analysis as well as biophysical single-pair Förster resonance energy transfer, we now provide evidence that negative cofactor-2 (NC2) induces dynamic conformational changes in the TBP-DNA complex that allow it to escape and return to TATA-binding mode. This can lead to movement of TBP along the DNA away from TATA.
Collapse
|
37
|
Izzi L, Silvestri C, von Both I, Labbé E, Zakin L, Wrana JL, Attisano L. Foxh1 recruits Gsc to negatively regulate Mixl1 expression during early mouse development. EMBO J 2007; 26:3132-43. [PMID: 17568773 PMCID: PMC1914101 DOI: 10.1038/sj.emboj.7601753] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2006] [Accepted: 05/21/2007] [Indexed: 01/10/2023] Open
Abstract
Mixl1 is a member of the Mix/Bix family of paired-like homeodomain proteins and is required for proper axial mesendoderm morphogenesis and endoderm formation during mouse development. Mix/Bix proteins are transcription factors that function in Nodal-like signaling pathways and are themselves regulated by Nodal. Here, we show that Foxh1 forms a DNA-binding complex with Smads to regulate transforming growth factor beta (TGFbeta)/Nodal-dependent Mixl1 gene expression. Whereas Foxh1 is commonly described as a transcriptional activator, we observed that Foxh1-null embryos exhibit expanded and enhanced Mixl1 expression during gastrulation, indicating that Foxh1 negatively regulates expression of Mixl1 during early mouse embryogenesis. We demonstrate that Foxh1 associates with the homeodomain-containing protein Goosecoid (Gsc), which in turn recruits histone deacetylases to repress Mixl1 gene expression. Ectopic expression of Gsc in embryoid bodies represses endogenous Mixl1 expression and this effect is dependent on Foxh1. As Gsc is itself induced in a Foxh1-dependent manner, we propose that Foxh1 initiates positive and negative transcriptional circuits to refine cell fate decisions during gastrulation.
Collapse
Affiliation(s)
- Luisa Izzi
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
- Terence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Ontario, Canada
| | - Cristoforo Silvestri
- Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada
- Terence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Ontario, Canada
| | - Ingo von Both
- Program in Molecular Biology and Cancer, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Etienne Labbé
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
- Terence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Ontario, Canada
| | - Lise Zakin
- Howard Hughes Medical Institute and Department of Biological Chemistry, University of California, Los Angeles, CA, USA
| | - Jeffrey L Wrana
- Program in Molecular Biology and Cancer, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
- Department of Medical Genetics and Microbiology, University of Toronto, Toronto, Ontario, Canada
| | - Liliana Attisano
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
- Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada
- Terence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
- Department of Biochemistry, Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Room 1008, 160 College Street, Toronto, Ontario, Canada M5S 3E1. Tel.: +1 416 946 3129; Fax: +1 416 978 8287; E-mail:
| |
Collapse
|
38
|
Abstract
During early mouse embryogenesis, temporal and spatial regulation of gene expression and cell signalling influences lineage specification, embryonic polarity, the patterning of tissue progenitors and the morphogenetic movement of cells and tissues. Uniquely in mammals, the extraembryonic tissues are the source of signals for lineage specification and tissue patterning. Here we discuss recent discoveries about the lead up to gastrulation, including early manifestations of asymmetry, coordination of cell and tissue movements and the interactions of transcription factors and signalling activity for lineage allocation and germ-layer specification.
Collapse
Affiliation(s)
- Patrick P L Tam
- Embryology Unit, Children's Medical Research Institute and Faculty of Medicine, University of Sydney, Westmead, NSW 2145, Australia.
| | | |
Collapse
|
39
|
Yun CH, Choi SC, Park E, Kim SJ, Chung AS, Lee HK, Lee HJ, Han JK. Negative regulation of Activin/Nodal signaling by SRF during Xenopus gastrulation. Development 2007; 134:769-77. [PMID: 17259304 DOI: 10.1242/dev.02778] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Activin/Nodal signaling is essential for germ-layer formation and axial patterning during embryogenesis. Recent evidence has demonstrated that the intra- or extracellular inhibition of this signaling is crucial for ectoderm specification and correct positioning of mesoderm and endoderm. Here, we analyzed the function of Xenopus serum response factor (XSRF) in establishing germ layers during early development. XSRF transcripts are restricted to the animal pole ectoderm in Xenopus early embryos. Ectopic expression of XSRF RNA suppresses mesoderm induction, both in the marginal zone in vivo and caused by Activin/Nodal signals in animal caps. Dominant-negative mutant or antisense morpholino oligonucleotide-mediated inhibition of XSRF function expands the expression of mesendodermal genes toward the ectodermal territory and enhances the inducing activity of the Activin signal. SRF interacts with Smad2 and FAST-1, and inhibits the formation of the Smad2-FAST-1 complex induced by Activin. These results suggest that XSRF might act to ensure proper mesoderm induction in the appropriate region by inhibiting the mesoderm-inducing signals during early embryogenesis.
Collapse
Affiliation(s)
- Chang-Hyun Yun
- Natural Medicines Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 305-333, Korea
| | | | | | | | | | | | | | | |
Collapse
|
40
|
Abstract
Nodal-related ligands of the transforming growth factor-beta (TGFbeta) superfamily play central roles in patterning the early embryo during the induction of mesoderm and endoderm and the specification of left-right asymmetry. Additional roles for this pathway in the maintenance of embryonic stem cell pluripotency and in carcinogenesis have been uncovered more recently. Consistent with its crucial developmental functions, Nodal signaling is tightly regulated by diverse mechanisms including the control of ligand processing, utilization of co-receptors, expression of soluble antagonists, as well as positive- and negative-feedback activities.
Collapse
Affiliation(s)
- Michael M Shen
- Center for Advanced Biotechnology and Medicine and Department of Pediatrics, UMDNJ-Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA
| |
Collapse
|
41
|
Vallier L, Pedersen RA. Human embryonic stem cells: an in vitro model to study mechanisms controlling pluripotency in early mammalian development. ACTA ACUST UNITED AC 2007; 1:119-30. [PMID: 17142846 DOI: 10.1385/scr:1:2:119] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The property of pluripotency confers the capacity for differentiation into a large number of cell types including extra-embryonic, somatic and germinal cells. During normal development, pluripotency is acquired by the cells of the early embryo, which shortly thereafter undergo differentiation, whereas embryonic stem cells (ESCs) uniquely maintain pluripotency while undergoing extensive in vitro proliferation. Studies using ESCs have begun to unravel the network of cytokines and transcription factors responsible for their maintenance of pluripotency. Surprisingly, mouse and human ESCs display significant differences in such mechanisms despite their similar embryonic origins. In this review, we compare the properties of pluripotent embryonic cells with those of ESCs to establish a general model for the mechanisms maintaining pluripotency. We first consider whether mouse and human ESCs represent comparable stages of early embryonic development. We then describe how human embryoid body (EB) differentiation could be used as a model of embryonic development. Finally, to concretely illustrate the discussion, we discuss our recent results concerning Nodal function in controlling cell fate at early stages of human EB development. With the new perspective of these findings, we suggest a previously unrecognized role of TGF-beta pathway signaling in maintaining pluripotency at early stages of mammalian embryonic development.
Collapse
Affiliation(s)
- Ludovic Vallier
- Department of Surgery and Cambride Institute for Medical Research Addenbrooke's Hospital, University of Cambridge, Cambridge CB2 2XY, UK.
| | | |
Collapse
|
42
|
Steiner AB, Engleka MJ, Lu Q, Piwarzyk EC, Yaklichkin S, Lefebvre JL, Walters JW, Pineda-Salgado L, Labosky PA, Kessler DS. FoxD3 regulation of Nodal in the Spemann organizer is essential for Xenopus dorsal mesoderm development. Development 2006; 133:4827-38. [PMID: 17092955 PMCID: PMC1676154 DOI: 10.1242/dev.02663] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Induction and patterning of the mesodermal germ layer is a key early step of vertebrate embryogenesis. We report that FoxD3 function in the Xenopus gastrula is essential for dorsal mesodermal development and for Nodal expression in the Spemann organizer. In embryos and explants, FoxD3 induced mesodermal genes, convergent extension movements and differentiation of axial tissues. Engrailed-FoxD3, but not VP16-FoxD3, was identical to native FoxD3 in mesoderm-inducing activity, indicating that FoxD3 functions as a transcriptional repressor to induce mesoderm. Antagonism of FoxD3 with VP16-FoxD3 or morpholino-knockdown of FoxD3 protein resulted in a complete block to axis formation, a loss of mesodermal gene expression, and an absence of axial mesoderm, indicating that transcriptional repression by FoxD3 is required for mesodermal development. FoxD3 induced mesoderm in a non-cell-autonomous manner, indicating a role for secreted inducing factors in the response to FoxD3. Consistent with this mechanism, FoxD3 was necessary and sufficient for the expression of multiple Nodal-related genes, and inhibitors of Nodal signaling blocked mesoderm induction by FoxD3. Therefore, FoxD3 is required for Nodal expression in the Spemann organizer and this function is essential for dorsal mesoderm formation.
Collapse
Affiliation(s)
- Aaron B. Steiner
- Department of Cell and Developmental Biology University of Pennsylvania School of Medicine 1110 BRB 2/3, 421 Curie Boulevard Philadelphia, PA 19104, USA Tel: 215-898-1478 Fax: 215-573-7601
| | - Mark J. Engleka
- Department of Cell and Developmental Biology University of Pennsylvania School of Medicine 1110 BRB 2/3, 421 Curie Boulevard Philadelphia, PA 19104, USA Tel: 215-898-1478 Fax: 215-573-7601
| | - Qun Lu
- Department of Cell and Developmental Biology University of Pennsylvania School of Medicine 1110 BRB 2/3, 421 Curie Boulevard Philadelphia, PA 19104, USA Tel: 215-898-1478 Fax: 215-573-7601
| | - Eileen C. Piwarzyk
- Department of Cell and Developmental Biology University of Pennsylvania School of Medicine 1110 BRB 2/3, 421 Curie Boulevard Philadelphia, PA 19104, USA Tel: 215-898-1478 Fax: 215-573-7601
| | - Sergey Yaklichkin
- Department of Cell and Developmental Biology University of Pennsylvania School of Medicine 1110 BRB 2/3, 421 Curie Boulevard Philadelphia, PA 19104, USA Tel: 215-898-1478 Fax: 215-573-7601
| | - Julie L. Lefebvre
- Department of Cell and Developmental Biology University of Pennsylvania School of Medicine 1110 BRB 2/3, 421 Curie Boulevard Philadelphia, PA 19104, USA Tel: 215-898-1478 Fax: 215-573-7601
| | - James W. Walters
- Department of Cell and Developmental Biology University of Pennsylvania School of Medicine 1110 BRB 2/3, 421 Curie Boulevard Philadelphia, PA 19104, USA Tel: 215-898-1478 Fax: 215-573-7601
| | - Liliam Pineda-Salgado
- Department of Cell and Developmental Biology University of Pennsylvania School of Medicine 1110 BRB 2/3, 421 Curie Boulevard Philadelphia, PA 19104, USA Tel: 215-898-1478 Fax: 215-573-7601
| | | | | |
Collapse
|
43
|
Lewis SL, Tam PPL. Definitive endoderm of the mouse embryo: formation, cell fates, and morphogenetic function. Dev Dyn 2006; 235:2315-29. [PMID: 16752393 DOI: 10.1002/dvdy.20846] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The endoderm is one of the primary germ layers but, in comparison to ectoderm and mesoderm, has received less attention. The definitive endoderm forms during gastrulation and replaces the extraembryonic visceral endoderm. It participates in the complex morphogenesis of the gut tube and contributes to the associated visceral organs. This review highlights the role of the definitive endoderm as a source of patterning cues for the morphogenesis of other germ-layer tissues, such as the anterior neurectoderm and the pharyngeal region, and also emphasizes the intricate patterning that the endoderm itself undergoes enabling the acquisition of regionalized cell fates.
Collapse
Affiliation(s)
- Samara L Lewis
- Embryology Unit, Children's Medical Research Institute, University of Sydney, Sydney, NSW, Australia
| | | |
Collapse
|
44
|
Miura S, Davis S, Klingensmith J, Mishina Y. BMP signaling in the epiblast is required for proper recruitment of the prospective paraxial mesoderm and development of the somites. Development 2006; 133:3767-75. [PMID: 16943278 DOI: 10.1242/dev.02552] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Bmpr1a encodes the BMP type IA receptor for bone morphogenetic proteins (BMPs), including 2 and 4. Here, we use mosaic inactivation of Bmpr1a in the epiblast of the mouse embryo (Bmpr-MORE embryos) to assess functions of this gene in mesoderm development. Unlike Bmpr1a-null embryos, which fail to gastrulate, Bmpr-MORE embryos initiate gastrulation, but the recruitment of prospective paraxial mesoderm cells to the primitive streak is delayed. This delay causes a more proximal distribution of cells with paraxial mesoderm character within the primitive streak, resulting in a lateral expansion of somitic mesoderm to form multiple columns. Inhibition of FGF signaling restores the normal timing of recruitment of prospective paraxial mesoderm and partially rescues the development of somites. This suggests that BMP and FGF signaling function antagonistically during paraxial mesoderm development.
Collapse
MESH Headings
- Animals
- Body Patterning/genetics
- Bone Morphogenetic Protein Receptors, Type I/antagonists & inhibitors
- Bone Morphogenetic Protein Receptors, Type I/genetics
- Bone Morphogenetic Protein Receptors, Type I/physiology
- Bone Morphogenetic Proteins/physiology
- Embryonic Development/genetics
- Fibroblast Growth Factors/antagonists & inhibitors
- Fibroblast Growth Factors/genetics
- Fibroblast Growth Factors/physiology
- Mesoderm/cytology
- Mesoderm/physiology
- Mice
- Mice, Mutant Strains
- Receptor, Fibroblast Growth Factor, Type 1/antagonists & inhibitors
- Receptor, Fibroblast Growth Factor, Type 1/genetics
- Receptor, Fibroblast Growth Factor, Type 1/physiology
- Signal Transduction/genetics
- Somites/cytology
- Somites/physiology
Collapse
Affiliation(s)
- Shigeto Miura
- Laboratory of Reproductive and Developmental Toxicology, National Institute of Environmental Health Sciences, MD C4-10, C458, Research Triangle Park, NC 27709, USA
| | | | | | | |
Collapse
|
45
|
Camus A, Perea-Gomez A, Moreau A, Collignon J. Absence of Nodal signaling promotes precocious neural differentiation in the mouse embryo. Dev Biol 2006; 295:743-55. [PMID: 16678814 DOI: 10.1016/j.ydbio.2006.03.047] [Citation(s) in RCA: 159] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2006] [Accepted: 03/31/2006] [Indexed: 12/25/2022]
Abstract
After implantation, mouse embryos deficient for the activity of the transforming growth factor-beta member Nodal fail to form both the mesoderm and the definitive endoderm. They also fail to specify the anterior visceral endoderm, a specialized signaling center which has been shown to be required for the establishment of anterior identity in the epiblast. Our study reveals that Nodal-/- epiblast cells nevertheless express prematurely and ectopically molecular markers specific of anterior fate. Our analysis shows that neural specification occurs and regional identities characteristic of the forebrain are established precociously in the Nodal-/- mutant with a sequential progression equivalent to that of wild-type embryo. When explanted and cultured in vitro, Nodal-/- epiblast cells readily differentiate into neurons. Genes normally transcribed in organizer-derived tissues, such as Gsc and Foxa2, are also expressed in Nodal-/- epiblast. The analysis of Nodal-/-;Gsc-/- compound mutant embryos shows that Gsc activity plays no critical role in the acquisition of forebrain characters by Nodal-deficient cells. This study suggests that the initial steps of neural specification and forebrain development may take place well before gastrulation in the mouse and highlights a possible role for Nodal, at pregastrula stages, in the inhibition of anterior and neural fate determination.
Collapse
Affiliation(s)
- Anne Camus
- Laboratoire de Développement des Vertébrés, Institut Jacques Monod UMR 7592 CNRS, Universités Paris 6 et 7, 2 place Jussieu, 75251 Paris, France.
| | | | | | | |
Collapse
|
46
|
Chen C, Ware SM, Sato A, Houston-Hawkins DE, Habas R, Matzuk MM, Shen MM, Brown CW. The Vg1-related protein Gdf3 acts in a Nodal signaling pathway in the pre-gastrulation mouse embryo. Development 2006; 133:319-29. [PMID: 16368929 DOI: 10.1242/dev.02210] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The formation of the anterior visceral endoderm (AVE) in the pre-gastrulation mouse embryo represents a crucial event in patterning of the anterior-posterior axis. Here, we show that the transforming growth factor beta (Tgfbeta) family member Gdf3 (growth-differentiation factor 3), a close relative of Xenopus Vg1, resembles the Tgfbeta ligand Nodal in both its signaling activity and its role in AVE formation in vivo. Thus, in cell culture, Gdf3 signaling requires the EGF-CFC co-receptor Cripto and can be inhibited by Lefty antagonists. In Xenopus embryos, Gdf3 misexpression results in secondary axis formation, and induces morphogenetic elongation and mesendoderm formation in animal caps. In mouse embryos, Gdf3 is expressed in the inner cell mass and epiblast, and null mutants frequently exhibit abnormal formation or positioning of the AVE. This phenotype correlates with defects in mesoderm and definitive endoderm formation, as well as abnormal Nodal expression levels. Our findings indicate that Gdf3 acts in a Nodal-like signaling pathway in pre-gastrulation development, and provide evidence for the functional conservation of Vg1 activity in mice.
Collapse
Affiliation(s)
- Canhe Chen
- Center for Advanced Biotechnology and Medicine and Department of Pediatrics, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA
| | | | | | | | | | | | | | | |
Collapse
|
47
|
Castaño E, Rodríguez-Zapata L, Rodriguez HP, Möbius N. Native NC2 selectively represses incorrect transcription initiation. Mol Biol 2006. [DOI: 10.1134/s0026893306020105] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
48
|
Houston DW, Wylie C. MaternalXenopus Zic2negatively regulatesNodal-relatedgene expression during anteroposterior patterning. Development 2005; 132:4845-55. [PMID: 16207750 DOI: 10.1242/dev.02066] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
During the development of Xenopus laevis, maternal mRNAs and proteins stored in the egg direct early patterning events such as the specification of the dorsoventral axis and primary germ layers. In an expression screen to identify maternal factors important for early development, we isolated a truncated cDNA for maternal Zic2(tZic2), encoding a zinc-finger transcription factor. The predicted tZic2 protein lacked the N-terminal region, but retained the zinc-finger domain. When expressed in embryos, tZic2 inhibited head and axial development,and blocked the ability of full-length Zic2 to induce neural crest genes. Depletion of maternal Zic2 from oocytes, using antisense oligonucleotides, caused exogastrulation, anterior truncations and axial defects. We show that loss of maternal Zic2 results in persistent and increased expression of Xenopus nodal-related (Xnr) genes, except for Xnr4, and overall increased Nodal signaling. Injection of a Nodal antagonist, Cerberus-short, reduced the severity of head and axial defects in Zic2-depleted embryos. Depletion of Zic2 could not restore Xnr expression to embryos additionally depleted of VegT, a T-domain transcription factor and an activator of Xnr gene transcription. Taken together, our results suggest a role for maternal Zic2 in the suppression of Xnr genes in early development. ZIC2 is mutated in human holoprosencephaly (HPE), a severe defect in brain hemisphere separation,and these results strengthen the suggestion that increased Nodal-related activity is a cause of HPE.
Collapse
Affiliation(s)
- Douglas W Houston
- The University of Iowa, Department of Biological Sciences, 257 BB, Iowa City, IA 52246-1324, USA.
| | | |
Collapse
|
49
|
Suri C, Haremaki T, Weinstein DC. Xema, a foxi-class gene expressed in the gastrula stage Xenopus ectoderm, is required for the suppression of mesendoderm. Development 2005; 132:2733-42. [PMID: 15901660 PMCID: PMC3525708 DOI: 10.1242/dev.01865] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The molecular basis of vertebrate germ layer formation has been the focus of intense scrutiny for decades, and the inductive interactions underlying this process are well defined. Only recently, however, have studies demonstrated that the regulated inhibition of ectopic germ layer formation is also crucial for patterning the early vertebrate embryo. We report here the characterization of Xema (Xenopus Ectodermally-expressed Mesendoderm Antagonist), a novel member of the Foxi-subclass of winged-helix transcription factors that is involved in the suppression of ectopic germ layer formation in the frog, Xenopus laevis. Xema transcripts are restricted to the animal pole ectoderm during early Xenopus development. Ectopic expression of Xema RNA inhibits mesoderm induction, both by growth factors and in the marginal zone, in vivo. Conversely, introduction of antisense morpholino oligonucleotides directed against the Xema transcript stimulates the expression of a broad range of mesodermal and endodermal marker genes in the animal pole. Our studies demonstrate that Xema is both necessary and sufficient for the inhibition of ectopic mesendoderm in the cells of the presumptive ectoderm, and support a model in which Fox proteins function in part to restrict inappropriate germ layer development throughout the vertebrate embryo.
Collapse
|
50
|
Abstract
The TGF-beta superfamily members have important roles in controlling patterning and tissue formation in both invertebrates and vertebrates. Two types of signal transducers, receptors and Smads, mediate the signaling to regulate expression of their target genes. Despite of the relatively simple signal transduction pathway, many modulators have been found to contribute to a tight regulation of this pathway in a variety of mechanisms. This article reviews the negative regulation of TGF-beta signaling with focus on its roles in vertebrate development.
Collapse
Affiliation(s)
- Ye Guang Chen
- The State Key Laboratory of Biomembrane and Membrane Biotechnology, Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing 100084, China.
| | | |
Collapse
|