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Wei J, Zhang W, Jiang A, Peng H, Zhang Q, Li Y, Bi J, Wang L, Liu P, Wang J, Ge Y, Zhang L, Yu H, Li L, Wang S, Leng L, Chen K, Dong B. Temporospatial hierarchy and allele-specific expression of zygotic genome activation revealed by distant interspecific urochordate hybrids. Nat Commun 2024; 15:2395. [PMID: 38493164 PMCID: PMC10944513 DOI: 10.1038/s41467-024-46780-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 03/06/2024] [Indexed: 03/18/2024] Open
Abstract
Zygotic genome activation (ZGA) is a universal process in early embryogenesis of metazoan, when the quiescent zygotic nucleus initiates global transcription. However, the mechanisms related to massive genome activation and allele-specific expression (ASE) remain not well understood. Here, we develop hybrids from two deeply diverged (120 Mya) ascidian species to symmetrically document the dynamics of ZGA. We identify two coordinated ZGA waves represent early developmental and housekeeping gene reactivation, respectively. Single-cell RNA sequencing reveals that the major expression wave exhibits spatial heterogeneity and significantly correlates with cell fate. Moreover, allele-specific expression occurs in a species- rather than parent-related manner, demonstrating the divergence of cis-regulatory elements between the two species. These findings provide insights into ZGA in chordates.
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Affiliation(s)
- Jiankai Wei
- Fang Zongxi Center for Marine EvoDevo, MoE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao, 266237, China
- MoE Key Laboratory of Evolution and Marine Biodiversity, Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, 266003, China
| | - Wei Zhang
- Fang Zongxi Center for Marine EvoDevo, MoE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China
| | - An Jiang
- Fang Zongxi Center for Marine EvoDevo, MoE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China
| | - Hongzhe Peng
- Fang Zongxi Center for Marine EvoDevo, MoE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China
| | - Quanyong Zhang
- State Key Laboratory of Primate Biomedical Research and Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming, Yunnan, 650500, China
| | - Yuting Li
- Fang Zongxi Center for Marine EvoDevo, MoE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China
| | - Jianqing Bi
- Fang Zongxi Center for Marine EvoDevo, MoE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China
| | - Linting Wang
- National Center of Mathematics and Interdisciplinary Sciences, Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing, 100190, China
| | - Penghui Liu
- Fang Zongxi Center for Marine EvoDevo, MoE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China
| | - Jing Wang
- Fang Zongxi Center for Marine EvoDevo, MoE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China
| | - Yonghang Ge
- Fang Zongxi Center for Marine EvoDevo, MoE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China
| | - Liya Zhang
- State Key Laboratory of Primate Biomedical Research and Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming, Yunnan, 650500, China
| | - Haiyan Yu
- Fang Zongxi Center for Marine EvoDevo, MoE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China
| | - Lei Li
- National Center of Mathematics and Interdisciplinary Sciences, Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing, 100190, China
| | - Shi Wang
- Fang Zongxi Center for Marine EvoDevo, MoE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao, 266237, China
| | - Liang Leng
- Institute of Herbgenomics, Chengdu University of Traditional Chinese Medicine, Chengdu, 611137, China.
| | - Kai Chen
- State Key Laboratory of Primate Biomedical Research and Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming, Yunnan, 650500, China.
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), No. 1119 Haibin Rd, Nansha Dist., Guangzhou, 511458, China.
| | - Bo Dong
- Fang Zongxi Center for Marine EvoDevo, MoE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China.
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao, 266237, China.
- MoE Key Laboratory of Evolution and Marine Biodiversity, Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, 266003, China.
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Tokuoka M, Satou Y. A digital twin reproducing gene regulatory network dynamics of early Ciona embryos indicates robust buffers in the network. PLoS Genet 2023; 19:e1010953. [PMID: 37756274 PMCID: PMC10530022 DOI: 10.1371/journal.pgen.1010953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 09/01/2023] [Indexed: 09/29/2023] Open
Abstract
How gene regulatory networks (GRNs) encode gene expression dynamics and how GRNs evolve are not well understood, although these problems have been studied extensively. We created a digital twin that accurately reproduces expression dynamics of 13 genes that initiate expression in 32-cell ascidian embryos. We first showed that gene expression patterns can be manipulated according to predictions by this digital model. Next, to simulate GRN rewiring, we changed regulatory functions that represented their regulatory mechanisms in the digital twin, and found that in 55 of 100 cases, removal of a single regulator from a conjunctive clause of Boolean functions did not theoretically alter qualitative expression patterns of these genes. In other words, we found that more than half the regulators gave theoretically redundant temporal or spatial information to target genes. We experimentally substantiated that the expression pattern of Nodal was maintained without one of these factors, Zfpm, by changing the upstream regulatory sequence of Nodal. Such robust buffers of regulatory mechanisms may provide a basis of enabling developmental system drift, or rewiring of GRNs without changing expression patterns of downstream genes, during evolution.
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Affiliation(s)
- Miki Tokuoka
- Department of Zoology, Graduate School of Science, Kyoto University, Sakyo, Kyoto, Japan
| | - Yutaka Satou
- Department of Zoology, Graduate School of Science, Kyoto University, Sakyo, Kyoto, Japan
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Oda-Ishii I, Yu D, Satou Y. Two distinct motifs for Zic-r.a drive specific gene expression in two cell lineages. Development 2021; 148:269043. [PMID: 34100063 DOI: 10.1242/dev.199538] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 04/26/2021] [Indexed: 11/20/2022]
Abstract
Zic-r.a, a maternal transcription factor, specifies posterior fate in ascidian embryos. However, its direct target, Tbx6-r.b, does not contain typical Zic-r.a-binding sites in its regulatory region. Using an in vitro selection assay, we found that Zic-r.a binds to sites dissimilar to the canonical motif, by which it activates Tbx6-r.b in a sub-lineage of muscle cells. These sites with non-canonical motifs have weak affinity for Zic-r.a; therefore, it activates Tbx6-r.b only in cells expressing Zic-r.a abundantly. Meanwhile, we found that Zic-r.a expressed zygotically in late embryos activates neural genes through canonical sites. Because different zinc-finger domains of Zic-r.a are important for driving reporters with canonical and non-canonical sites, it is likely that the non-canonical motif is not a divergent version of the canonical motif. In other words, our data indicate that the non-canonical motif represents a motif distinct from the canonical motif. Thus, Zic-r.a recognizes two distinct motifs to activate two sets of genes at two timepoints in development. This article has an associated 'The people behind the papers' interview.
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Affiliation(s)
- Izumi Oda-Ishii
- Department of Zoology, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Deli Yu
- Department of Zoology, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Yutaka Satou
- Department of Zoology, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
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Tokuoka M, Maeda K, Kobayashi K, Mochizuki A, Satou Y. The gene regulatory system for specifying germ layers in early embryos of the simple chordate. SCIENCE ADVANCES 2021; 7:7/24/eabf8210. [PMID: 34108211 PMCID: PMC8189585 DOI: 10.1126/sciadv.abf8210] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Accepted: 04/23/2021] [Indexed: 06/12/2023]
Abstract
In animal embryos, gene regulatory networks control the dynamics of gene expression in cells and coordinate such dynamics among cells. In ascidian embryos, gene expression dynamics have been dissected at the single-cell resolution. Here, we revealed mathematical functions that represent the regulatory logics of all regulatory genes expressed at the 32-cell stage when the germ layers are largely specified. These functions collectively explain the entire mechanism by which gene expression dynamics are controlled coordinately in early embryos. We found that regulatory functions for genes expressed in each of the specific lineages contain a common core regulatory mechanism. Last, we showed that the expression of the regulatory genes became reproducible by calculation and controllable by experimental manipulations. Thus, these regulatory functions represent an architectural design for the germ layer specification of this chordate and provide a platform for simulations and experiments to understand the operating principles of gene regulatory networks.
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Affiliation(s)
- Miki Tokuoka
- Department of Zoology, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan
| | - Kazuki Maeda
- Faculty of Informatics, University of Fukuchiyama, 3370 Hori, Fukuchiyama, Kyoto 620-0886, Japan
| | - Kenji Kobayashi
- Department of Zoology, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan
| | - Atsushi Mochizuki
- Institute for Frontier Life and Medical Sciences, Kyoto University, Sakyo, Kyoto 606-8507, Japan
| | - Yutaka Satou
- Department of Zoology, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan.
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Cis-regulatory code for determining the action of Foxd as both an activator and a repressor in ascidian embryos. Dev Biol 2021; 476:11-17. [PMID: 33753082 DOI: 10.1016/j.ydbio.2021.03.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 02/25/2021] [Accepted: 03/14/2021] [Indexed: 11/21/2022]
Abstract
In early embryos of Ciona, an invertebrate chordate, the animal-vegetal axis is established by the combinatorial actions of maternal factors. One target of these maternal factors, Foxd, is specifically expressed in the vegetal hemisphere and stabilizes the animal-vegetal axis by activating vegetal hemisphere-specific genes and repressing animal hemisphere-specific genes. This dual functionality is essential for the embryogenesis of early ascidian embryos; however, the mechanism by which Foxd can act as both a repressor and an activator is unknown. Here, we identify a Foxd binding site upstream of Lhx3/4, which is activated by Foxd, and compare it with a repressive Foxd binding site upstream of Dmrt.a. We found that activating sites bind Foxd with low affinity while repressive sites bind Foxd with high affinity. Reporter assays confirm that this qualitative difference between activating and repressive Foxd binding sites is sufficient to change Foxd functionality. We therefore conclude that the outcome of Foxd transcriptional regulation is encoded in cis-regulatory elements.
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Liu B, Satou Y. The genetic program to specify ectodermal cells in ascidian embryos. Dev Growth Differ 2020; 62:301-310. [PMID: 32130723 DOI: 10.1111/dgd.12660] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Revised: 02/11/2020] [Accepted: 02/21/2020] [Indexed: 12/18/2022]
Abstract
The ascidian belongs to the sister group of vertebrates and shares many features with them. The gene regulatory network (GRN) controlling gene expression in ascidian embryonic development leading to the tadpole larva has revealed evolutionarily conserved gene circuits between ascidians and vertebrates. These conserved mechanisms are indeed useful to infer the original developmental programs of the ancestral chordates. Simultaneously, these studies have revealed which gene circuits are missing in the ascidian GRN; these gene circuits may have been acquired in the vertebrate lineage. In particular, the GRN responsible for gene expression in ectodermal cells of ascidian embryos has revealed the genetic programs that regulate the regionalization of the brain, formation of palps derived from placode-like cells, and differentiation of sensory neurons derived from neural crest-like cells. We here discuss how these studies have given insights into the evolution of these traits.
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Affiliation(s)
- Boqi Liu
- Department of Zoology, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Yutaka Satou
- Department of Zoology, Graduate School of Science, Kyoto University, Kyoto, Japan
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Imai KS, Kobayashi K, Kari W, Rothbächer U, Ookubo N, Oda-Ishii I, Satou Y. Gata is ubiquitously required for the earliest zygotic gene transcription in the ascidian embryo. Dev Biol 2019; 458:215-227. [PMID: 31751550 DOI: 10.1016/j.ydbio.2019.11.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2019] [Revised: 11/13/2019] [Accepted: 11/13/2019] [Indexed: 10/25/2022]
Abstract
In ascidian embryos, the earliest transcription from the zygotic genome begins between the 8-cell and 16-cell stages. Gata.a, a maternally expressed Gata transcription factor, activates target genes specifically in the animal hemisphere, whereas the complex of β-catenin and Tcf7 antagonizes the activity of Gata.a and activates target genes specifically in the vegetal hemisphere. Here, we show that genes zygotically expressed at the 16-cell stage have significantly more Gata motifs in their upstream regions. These genes included not only genes with animal hemisphere-specific expression but also genes with vegetal hemisphere-specific expression. On the basis of this finding, we performed knockdown experiments for Gata.a and reporter assays, and found that Gata.a is required for the expression of not only genes with animal hemisphere-specific expression, but also genes with vegetal hemisphere-specific expression. Our data indicated that weak Gata.a activity that cannot induce animal hemisphere-specific expression can allow β-catenin/Tcf7 targets to be expressed in the vegetal cells. Because genes zygotically expressed at the 32-cell stage also had significantly more Gata motifs in their upstream regions, Gata.a function may not be limited to the genes expressed specifically in the animal or vegetal hemispheres at the 16-cell stage, and Gata.a may play an important role in the earliest transcription of the zygotic genome.
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Affiliation(s)
- Kaoru S Imai
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, 560-0043, Japan.
| | - Kenji Kobayashi
- Department of Zoology, Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan
| | - Willi Kari
- Department of Evolution and Developmental Biology, Zoological Institute, University, Innsbruck, Innsbruck, Austria
| | - Ute Rothbächer
- Department of Evolution and Developmental Biology, Zoological Institute, University, Innsbruck, Innsbruck, Austria
| | - Naoki Ookubo
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, 560-0043, Japan
| | - Izumi Oda-Ishii
- Department of Zoology, Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan
| | - Yutaka Satou
- Department of Zoology, Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan
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