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Iguchi R, Usui K, Nakayama S, Sasakura Y, Sekiguchi T, Ogasawara M. Multi-regional expression of pancreas-related digestive enzyme genes in the intestinal chamber of the ascidian Ciona intestinalis type A. Cell Tissue Res 2023; 394:423-430. [PMID: 37878073 DOI: 10.1007/s00441-023-03839-6] [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: 02/24/2023] [Accepted: 10/17/2023] [Indexed: 10/26/2023]
Abstract
Bilateria share sequential steps in their digestive systems, and digestion occurs in a pre-absorption step within a chamber-like structure. Previous studies on the ascidian Ciona intestinalis type A, an evolutionary research model of vertebrate organs, revealed that Ciona homologs of pancreas-related exocrine digestive enzymes (XDEs) are exclusively expressed in the chamber-like bulging stomach. In the development of the gastrointestinal tract, genes for the pancreas-related transcription factors, namely Ptf1a, Nr5a2, and Pdx, are expressed near the stomach. Recent organ/tissue RNA-seq studies on two Ciona species reported that transcripts of the XDE homologs exist in the intestinal regions, as well as in the stomach. In the present study, we investigated the spatial gene expression of XDE homologs in the gastrointestinal region of the C. intestinalis type A. Whole-mount in situ hybridization using adult and juvenile specimens revealed apparent expression signals of XDE homologs in a small number of gastrointestinal epithelial cells. Furthermore, two pancreas-related transcription factor genes, Nr5a2 and Pdx, exhibited multi-regional expression along the Ciona juvenile intestines. These results imply that ascidians may form multiple digestive regions corresponding to the vertebrate pancreas.
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Affiliation(s)
- Rin Iguchi
- Department of Biology, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
| | - Kanae Usui
- Department of Biology, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
| | - Satoshi Nakayama
- Department of Biology, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
| | - Yasunori Sasakura
- Shimoda Marine Research Center, University of Tsukuba, 5-10-1 Shimoda, Shizuoka, 415-0025, Japan
| | - Toshio Sekiguchi
- The Noto Marine Laboratory, Division of Marine Environmental Studies, Institute of Nature and Environmental Technology, Kanazawa University, Kanazawa, Housu-gun, Ishikawa, 927-0553, Japan
| | - Michio Ogasawara
- Department of Biology, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan.
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Iguchi R, Nakayama S, Sasakura Y, Sekiguchi T, Ogasawara M. Repetitive and zonal expression profiles of absorption-related genes in the gastrointestinal tract of ascidian Ciona intestinalis type A. Cell Tissue Res 2023; 394:343-360. [PMID: 37670165 DOI: 10.1007/s00441-023-03828-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 08/15/2023] [Indexed: 09/07/2023]
Abstract
Intestinal absorption is essential for heterotrophic bilaterians with a tubular gut. Although the fundamental features of the digestive system were shared among chordates with evolution, the gut morphologies of vertebrates diverged and adapted to different food habitats. The ascidian Ciona intestinalis type A, a genome-wide research model of basal chordates, is used to examine the functional morphology of the intestines because of its transparent juvenile body. In the present study, the characteristic gene expression patterns (GEP) of Ciona absorptive proteins, e.g., brush border membrane enzymes for terminal digestion (lactase, maltase, APA, and APN) and transporters (SGLT1, GLUT5, PEPT1, and B0AT1), were investigated in juveniles and young adults, with a special reference to the absorption of other nutrients by pinocytosis- and phagocytosis-related proteins (megalin, cubilin, amnionless, Dab2, Rab7, LAMP, cathepsins, and MRC1). Whole-mount in situ hybridization revealed that these GEP showed multi-regional and repetitive features along the Ciona gastrointestinal tract, mainly in the stomach and several regions of the intestines. In young adults, many absorption-related genes, including pinocytosis-/phagocytosis-related genes, were also expressed between the stomach and mid-intestine. In the gastrointestinal epithelium, absorption-related genes showed zonal GEP along the epithelial structure. Comparisons of GEP, including other intestinal functions, such as nutrient digestion and intestinal protection, indicated the repetitive assignment of a well-coordinated set of intestinal GEP in the Ciona gastrointestinal tract.
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Affiliation(s)
- Rin Iguchi
- Department of Biology, Graduate School of Science, Chiba University, 1-33 Yayoi-Cho, Inage-Ku, Chiba, 263-8522, Japan
| | - Satoshi Nakayama
- Department of Biology, Graduate School of Science, Chiba University, 1-33 Yayoi-Cho, Inage-Ku, Chiba, 263-8522, Japan
| | - Yasunori Sasakura
- Shimoda Marine Research Center, University of Tsukuba, 5-10-1 Shimoda, Shizuoka, 415-0025, Japan
| | - Toshio Sekiguchi
- The Noto Marine Laboratory, Division of Marine Environmental Studies, Institute of Nature and Environmental Technology, Kanazawa University, Housu-Gun, Ishikawa, 927-0553, Japan
| | - Michio Ogasawara
- Department of Biology, Graduate School of Science, Chiba University, 1-33 Yayoi-Cho, Inage-Ku, Chiba, 263-8522, Japan.
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Chan S, Shen D, Sang Y, Wang S, Wang Y, Chen C, Gao B, Song C. Development of enhancer-trapping and -detection vectors mediated by the Tol2 transposon in zebrafish. PeerJ 2019; 7:e6862. [PMID: 31106068 PMCID: PMC6499061 DOI: 10.7717/peerj.6862] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 03/28/2019] [Indexed: 01/02/2023] Open
Abstract
Enhancers are key transcriptional drivers of gene expression. The identification of enhancers in the genome is central for understanding gene-expression programs. Although transposon-mediated enhancer trapping (ET) is a powerful approach to the identification of enhancers in zebrafish, its efficiency varies considerably. To improve the ET efficiency, we constructed Tol2-mediated ET vectors with a reporter gene (mCherry) expression box driven by four minimal promoters (Gata, Myc, Krt4 and Oct4), respectively. The ET efficiency and expression background were compared among the four promoters by zebrafish embryo injection at the one-cell stage. The results showed that the Gata minimal promoter yielded the lowest basic expression and the second-highest trapping efficiency (44.6% at 12 hpf (hour post-fertilization) and 23.1% at 72 hpf, n = 305 and n = 307). The Krt4 promoter had the highest trapping efficiency (64% at 12 hpf and 67.1% at 72 hpf, n = 302 and n = 301) and the strongest basic expression. To detect enhancer activity, chicken 5′HS4 double insulators were cloned into the two ET vectors with the Gata or Krt4 minimal promoter, flanking the mCherry expression box. The resulting detection vectors were injected into zebrafish embryos. mCherry expression driven by the Gata promoter (about 5%, n = 301) was decreased significantly compared with that observed for embryos injected with the ET vectors (23% at 72 hpf, n = 308). These results suggest that the insulators block the genome-position effects and that this vector is fit for enhancer-activity evaluation. To assess the compatibility between the enhancers and the minimal promoters, four enhancers (CNS1, Z48, Hand2 and Hs769) were cloned upstream of the Gata or Beta-globin minimal promoter in the enhancer-activity-detection vectors. The resulting recombinant vectors were assayed by zebrafish embryo injection. We found that Z48 and CNS1 responded to the Gata minimal promoter, and that Hand2 only responded to the Beta-globin minimal promoter. In contrast, Hs769 did not respond to either the Gata or Beta-globin minimal promoters. These results suggest the existence of compatibility between enhancers and minimal promoters. This study represents a systematic approach to the discovery of optional ET and enhancer-detection vectors. We are eager to provide a superior tool for understanding functional genomics.
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Affiliation(s)
- Shuheng Chan
- Yangzhou University, Institute of Animal Mobilome and Genome, College of Animal Science & Technology, Yangzhou, Jiangsu, China
| | - Dan Shen
- Yangzhou University, Institute of Animal Mobilome and Genome, College of Animal Science & Technology, Yangzhou, Jiangsu, China
| | - Yatong Sang
- Yangzhou University, Institute of Animal Mobilome and Genome, College of Animal Science & Technology, Yangzhou, Jiangsu, China
| | - Saisai Wang
- Yangzhou University, Institute of Animal Mobilome and Genome, College of Animal Science & Technology, Yangzhou, Jiangsu, China
| | - Yali Wang
- Yangzhou University, Institute of Animal Mobilome and Genome, College of Animal Science & Technology, Yangzhou, Jiangsu, China
| | - Cai Chen
- Yangzhou University, Institute of Animal Mobilome and Genome, College of Animal Science & Technology, Yangzhou, Jiangsu, China
| | - Bo Gao
- Yangzhou University, Institute of Animal Mobilome and Genome, College of Animal Science & Technology, Yangzhou, Jiangsu, China
| | - Chengyi Song
- Yangzhou University, Institute of Animal Mobilome and Genome, College of Animal Science & Technology, Yangzhou, Jiangsu, China
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Sasakura Y, Hozumi A. Formation of adult organs through metamorphosis in ascidians. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2017; 7. [PMID: 29105358 DOI: 10.1002/wdev.304] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 08/28/2017] [Accepted: 09/11/2017] [Indexed: 02/05/2023]
Abstract
The representative characteristic of ascidians is their vertebrate-like, tadpole shape at the larval stage. Ascidians lose the tadpole shape through metamorphosis to become adults with a nonmotile, sessile body and a shape generally considered distinct from that of vertebrates. Solitary ascidians including Ciona species are extensively studied to understand the developmental mechanisms of ascidians, and to compare these mechanisms with their counterparts in vertebrates. In these ascidian species, the digestive and circulatory systems are not well developed in the larval trunk and the larvae do not take food. This is in contrast with the inner conditions of vertebrate tadpoles, which have functional organs comparable to those of adults. The adult organs and tissues of these ascidians become functional during metamorphosis that is completed quickly, suggesting that the ascidian larvae of solitary species are a transient stage of development. We here discuss how the cells and tissues in the ascidian larval body are converted into those of adults. The hearts of ascidians and vertebrates use closely related cellular and molecular mechanisms that suggest their shared origin. Hox genes of ascidians are essential for forming adult endodermal structures. To fully understand the development and evolution of chordates, a complete elucidation of the mechanisms underlying the adult tissue/organ formation of ascidians will be needed. WIREs Dev Biol 2018, 7:e304. doi: 10.1002/wdev.304 This article is categorized under: Comparative Development and Evolution > Body Plan Evolution Early Embryonic Development > Development to the Basic Body Plan.
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Affiliation(s)
- Yasunori Sasakura
- Shimoda Marine Research Center, University of Tsukuba, Shimoda, Shizuoka, Japan
| | - Akiko Hozumi
- Shimoda Marine Research Center, University of Tsukuba, Shimoda, Shizuoka, Japan
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Germ cell regeneration-mediated, enhanced mutagenesis in the ascidian Ciona intestinalis reveals flexible germ cell formation from different somatic cells. Dev Biol 2017; 423:111-125. [DOI: 10.1016/j.ydbio.2017.01.022] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 01/12/2017] [Accepted: 01/31/2017] [Indexed: 11/22/2022]
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Yoshida K, Nakahata A, Treen N, Sakuma T, Yamamoto T, Sasakura Y. Hox-mediated endodermal identity patterns the pharyngeal muscle formation in the chordate pharynx. Development 2017; 144:1629-1634. [DOI: 10.1242/dev.144436] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Accepted: 03/07/2017] [Indexed: 01/10/2023]
Abstract
The pharynx, possessing gill slits and the endostyle, is a characteristic of chordates that is a complex of multiple tissues well organized along the anterior-posterior (AP) axis. Although Hox genes show AP coordinated expression in the pharyngeal endoderm, tissue specific roles of these factors for establishing the regional identities within this tissue is largely unknown. Here, we show that Hox1 is essential for the establishment of AP axial identity of the endostyle, a major structure of the pharyngeal endoderm, in the ascidian Ciona intestinalis. We found that Hox1 knockout causes posterior to anterior transformation of the endostyle identity, and Hox1 represses Otx expression and anterior identity, and vice versa. Furthermore, alteration of the regional identity of the endostyle disrupts the formation of body wall muscles, suggesting that the endodermal axial identity is essential for the coordinated pharyngeal development. Our results reveal an essential role of Hox genes for establishment of the AP regional identity in the pharyngeal endoderm and crosstalk between endoderm and mesoderm for the development of chordate pharynx.
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Affiliation(s)
- Keita Yoshida
- Shimoda Marine Research Center, University of Tsukuba, 5-10-1 Shimoda, Shizuoka, 415-0025, Japan
| | - Azusa Nakahata
- Shimoda Marine Research Center, University of Tsukuba, 5-10-1 Shimoda, Shizuoka, 415-0025, Japan
| | - Nicholas Treen
- Shimoda Marine Research Center, University of Tsukuba, 5-10-1 Shimoda, Shizuoka, 415-0025, Japan
| | - Tetsushi Sakuma
- Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - Takashi Yamamoto
- Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - Yasunori Sasakura
- Shimoda Marine Research Center, University of Tsukuba, 5-10-1 Shimoda, Shizuoka, 415-0025, Japan
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7
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Ordered expression pattern of Hox and ParaHox genes along the alimentary canal in the ascidian juvenile. Cell Tissue Res 2016; 365:65-75. [DOI: 10.1007/s00441-016-2360-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 01/07/2016] [Indexed: 01/03/2023]
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8
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Kawai N, Ogura Y, Ikuta T, Saiga H, Hamada M, Sakuma T, Yamamoto T, Satoh N, Sasakura Y. Hox10-regulated endodermal cell migration is essential for development of the ascidian intestine. Dev Biol 2015; 403:43-56. [PMID: 25888074 DOI: 10.1016/j.ydbio.2015.03.018] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 03/25/2015] [Indexed: 11/17/2022]
Abstract
Hox cluster genes play crucial roles in development of the metazoan antero-posterior axis. Functions of Hox genes in patterning the central nervous system and limb buds are well known. They are also expressed in chordate endodermal tissues, where their roles in endodermal development are still poorly understood. In the invertebrate chordate, Ciona intestinalis, endodermal tissues are in a premature state during the larval stage, and they differentiate into the digestive tract during metamorphosis. In this study, we showed that disruption of a Hox gene, Ci-Hox10, prevented intestinal formation. Ci-Hox10-knock-down larvae displayed defective migration of endodermal strand cells. Formation of a protrusion, which is important for cell migration, was disrupted in these cells. The collagen type IX gene is a downstream target of Ci-Hox10, and is negatively regulated by Ci-Hox10 and a matrix metalloproteinase ortholog, prior to endodermal cell migration. Inhibition of this regulation prevented cellular migration. These results suggest that Ci-Hox10 regulates endodermal strand cell migration by forming a protrusion and by reconstructing the extracellular matrix.
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Affiliation(s)
- Narudo Kawai
- Shimoda Marine Research Center, University of Tsukuba, Shimoda, Shizuoka 415-0025, Japan.
| | - Yosuke Ogura
- Shimoda Marine Research Center, University of Tsukuba, Shimoda, Shizuoka 415-0025, Japan
| | - Tetsuro Ikuta
- Department of Biological Sciences, Graduate School of Science and Engineering, Tokyo Metropolitan University, 1-1 Minamioosawa, Hachiohji, Tokyo 192-0397, Japan; Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa 904-0495, Japan
| | - Hidetoshi Saiga
- Department of Biological Sciences, Graduate School of Science and Engineering, Tokyo Metropolitan University, 1-1 Minamioosawa, Hachiohji, Tokyo 192-0397, Japan
| | - Mayuko Hamada
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa 904-0495, Japan
| | - Tetsushi Sakuma
- Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan
| | - Takashi Yamamoto
- Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan
| | - Nori Satoh
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa 904-0495, Japan
| | - Yasunori Sasakura
- Shimoda Marine Research Center, University of Tsukuba, Shimoda, Shizuoka 415-0025, Japan
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Shiba K, Inaba K. Distinct roles of soluble and transmembrane adenylyl cyclases in the regulation of flagellar motility in Ciona sperm. Int J Mol Sci 2014; 15:13192-208. [PMID: 25073090 PMCID: PMC4159788 DOI: 10.3390/ijms150813192] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 05/06/2014] [Accepted: 07/11/2014] [Indexed: 12/31/2022] Open
Abstract
Adenylyl cyclase (AC) is a key enzyme that synthesizes cyclic AMP (cAMP) at the onset of the signaling pathway to activate sperm motility. Here, we showed that both transmembrane AC (tmAC) and soluble AC (sAC) are distinctly involved in the regulation of sperm motility in the ascidian Ciona intestinalis. A tmAC inhibitor blocked both cAMP synthesis and the activation of sperm motility induced by the egg factor sperm activating and attracting factor (SAAF), as well as those induced by theophylline, an inhibitor of phoshodiesterase. It also significantly inhibited cAMP-dependent phosphorylation of a set of proteins at motility activation. On the other hand, a sAC inhibitor does not affect on SAAF-induced transient increase of cAMP, motility activation or protein phosphorylation, but it reduced swimming velocity to half in theophylline-induced sperm. A sAC inhibitor KH-7 induced circular swimming trajectory with smaller diameter and significantly suppressed chemotaxis of sperm to SAAF. These results suggest that tmAC is involved in the basic mechanism for motility activation through cAMP-dependent protein phosphorylation, whereas sAC plays distinct roles in increase of flagellar beat frequency and in the Ca2+-dependent chemotactic movement of sperm.
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Affiliation(s)
- Kogiku Shiba
- Shimoda Marine Research Center, University of Tsukuba, Shimoda 5-10-1, Shizuoka 415-0025, Japan.
| | - Kazuo Inaba
- Shimoda Marine Research Center, University of Tsukuba, Shimoda 5-10-1, Shizuoka 415-0025, Japan.
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10
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Irvine SQ. Study of Cis-regulatory Elements in the Ascidian Ciona intestinalis. Curr Genomics 2013; 14:56-67. [PMID: 23997651 PMCID: PMC3580780 DOI: 10.2174/138920213804999192] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2012] [Revised: 12/30/2012] [Accepted: 01/01/2013] [Indexed: 01/31/2023] Open
Abstract
The ascidian (sea squirt) C. intestinalis has become an important model organism for the study of cis-regulation. This is largely due to the technology that has been developed for assessing cis-regulatory activity through the use of transient reporter transgenes introduced into fertilized eggs. This technique allows the rapid and inexpensive testing of endogenous or altered DNA for regulatory activity in vivo. This review examines evidence that C. intestinaliscis-regulatory elements are located more closely to coding regions than in other model organisms. I go on to compare the organization of cis-regulatory elements and conserved non-coding sequences in Ciona, mammals, and other deuterostomes for three representative C.intestinalis genes, Pax6, FoxAa, and the DlxA-B cluster, along with homologs in the other species. These comparisons point out some of the similarities and differences between cis-regulatory elements and their study in the various model organisms. Finally, I provide illustrations of how C. intestinalis lends itself to detailed study of the structure of cis-regulatory elements, which have led, and promise to continue to lead, to important insights into the fundamentals of transcriptional regulation.
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Affiliation(s)
- Steven Q Irvine
- Department of Biological Sciences, University of Rhode Island, Kingston, RI 02881, USA
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Nakazawa K, Yamazawa T, Moriyama Y, Ogura Y, Kawai N, Sasakura Y, Saiga H. Formation of the digestive tract inCiona intestinalisincludes two distinct morphogenic processes between its anterior and posterior parts. Dev Dyn 2013; 242:1172-83. [DOI: 10.1002/dvdy.24009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2013] [Revised: 05/02/2013] [Accepted: 05/17/2013] [Indexed: 11/07/2022] Open
Affiliation(s)
- Keiichi Nakazawa
- Department of Biological Sciences, Graduate School of Science and Engeneering; Tokyo Metropolitan University; Hachiohji Tokyo Japan
| | - Takumi Yamazawa
- Department of Biological Sciences, Graduate School of Science and Engeneering; Tokyo Metropolitan University; Hachiohji Tokyo Japan
| | - Yuuta Moriyama
- Department of Biological Sciences, Graduate School of Science and Engeneering; Tokyo Metropolitan University; Hachiohji Tokyo Japan
| | - Yosuke Ogura
- Shimoda Marine Research Center; University of Tsukuba; Shizuoka Japan
| | - Narudo Kawai
- Shimoda Marine Research Center; University of Tsukuba; Shizuoka Japan
| | - Yasunori Sasakura
- Shimoda Marine Research Center; University of Tsukuba; Shizuoka Japan
| | - Hidetoshi Saiga
- Department of Biological Sciences, Graduate School of Science and Engeneering; Tokyo Metropolitan University; Hachiohji Tokyo Japan
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12
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Enhancer activity sensitive to the orientation of the gene it regulates in the chordate genome. Dev Biol 2012; 375:79-91. [PMID: 23274690 DOI: 10.1016/j.ydbio.2012.12.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Revised: 11/22/2012] [Accepted: 12/13/2012] [Indexed: 12/26/2022]
Abstract
Enhancers are flexible in terms of their location and orientation relative to the genes they regulate. However, little is known about whether the flexibility can be applied in every combination of enhancers and genes. Enhancer detection with transposable elements is a powerful method to identify enhancers in the genome and to create marker lines expressing fluorescent proteins in a tissue-specific manner. In the chordate Ciona intestinalis, this method has been established with a Tc1/mariner superfamily transposon Minos. Previously, we created the enhancer detection line E[MiTSAdTPOG]15 (E15) that specifically expresses green fluorescent protein (GFP) in the central nervous system (CNS) after metamorphosis. In this study, we identified the causal insertion site of the transgenic line. There are two genes flanking the causal insertion of the E15 line, and the genomic region around the insertion site contains the enhancers responsible for the expression in the endostyle and gut in addition to the CNS. We found that the endostyle and gut enhancers show sensitivity to the orientation of the GFP gene for their enhancer activity. Namely, the enhancers cannot enhance the expression of GFP which is inserted at the same orientation as the E15 line, while the enhancers can enhance GFP expression inserted at the opposite orientation. The CNS enhancer can enhance GFP expression in both orientations. The DNA element adjacent to the endostyle enhancer is responsible for the orientation sensitivity of the enhancer. The different sensitivity of the enhancers to the orientation of the transgene is a cause of CNS-specific GFP expression in the E15 line.
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13
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Hozumi A, Mita K, Miskey C, Mates L, Izsvak Z, Ivics Z, Satake H, Sasakura Y. Germline transgenesis of the chordate Ciona intestinalis with hyperactive variants of sleeping beauty transposable element. Dev Dyn 2012; 242:30-43. [PMID: 23073965 DOI: 10.1002/dvdy.23891] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/09/2012] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND Transposon-mediated transgenesis is an excellent method for creating stable transgenic lines and insertional mutants. In the chordate Ciona intestinalis, Minos is the only transposon that has been used as the tool for germline transformation. Adding another transposon system in this organism enables us to conduct genetic techniques which can only be realized with the use of two transposons. RESULTS In the present study, we found that another Tc1/mariner superfamily transposon, sleeping beauty (SB), retains sufficient activity for germline transformation of C. intestinalis. SB shows efficiencies of germline transformation, insertion into gene coding regions, and enhancer detection comparable to those of Minos. We have developed a system for the remobilization of SB copies in the C. intestinalis genome by using transgenic lines expressing SB transposase in the germ cells. With this system, we examined the manner of SB mobilization in the C. intestinalis genome. SB shows intrachromosomal transposition more frequently than Minos. CONCLUSIONS SB-based germline transformation and the establishment of a new method that uses its frequent intrachromosomal transposition will result in breakthroughs in genetic approaches that use C. intestinalis together with Minos.
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Affiliation(s)
- Akiko Hozumi
- Shimoda Marine Research Center, University of Tsukuba, Shimoda, Shizuoka, Japan
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14
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Sasakura Y, Kanda M, Ikeda T, Horie T, Kawai N, Ogura Y, Yoshida R, Hozumi A, Satoh N, Fujiwara S. Retinoic acid-driven Hox1 is required in the epidermis for forming the otic/atrial placodes during ascidian metamorphosis. Development 2012; 139:2156-60. [PMID: 22573621 DOI: 10.1242/dev.080234] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Retinoic acid (RA)-mediated expression of the homeobox gene Hox1 is a hallmark of the chordate central nervous system (CNS). It has been suggested that the RA-Hox1 network also functions in the epidermal ectoderm of chordates. Here, we show that in the urochordate ascidian Ciona intestinalis, RA-Hox1 in the epidermal ectoderm is necessary for formation of the atrial siphon placode (ASP), a structure homologous to the vertebrate otic placode. Loss of Hox1 function resulted in loss of the ASP, which could be rescued by expressing Hox1 in the epidermis. As previous studies showed that RA directly upregulates Hox1 in the epidermis of Ciona larvae, we also examined the role of RA in ASP formation. We showed that abolishment of RA resulted in loss of the ASP, which could be rescued by forced expression of Hox1 in the epidermis. Our results suggest that RA-Hox1 in the epidermal ectoderm played a key role in the acquisition of the otic placode during chordate evolution.
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Affiliation(s)
- Yasunori Sasakura
- Shimoda Marine Research Center, University of Tsukuba, Shimoda, Shizuoka 415-0025, Japan.
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Sasakura Y, Mita K, Ogura Y, Horie T. Ascidians as excellent chordate models for studying the development of the nervous system during embryogenesis and metamorphosis. Dev Growth Differ 2012; 54:420-37. [DOI: 10.1111/j.1440-169x.2012.01343.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Yasunori Sasakura
- Shimoda Marine Research Center; University of Tsukuba; Shimoda; Shizuoka; 415-0025; Japan
| | - Kaoru Mita
- Shimoda Marine Research Center; University of Tsukuba; Shimoda; Shizuoka; 415-0025; Japan
| | - Yosuke Ogura
- Shimoda Marine Research Center; University of Tsukuba; Shimoda; Shizuoka; 415-0025; Japan
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