1
|
Saadi AJ, de Oliveira AL, Kocot KM, Schwaha T. Genomic and transcriptomic survey of bryozoan Hox and ParaHox genes with emphasis on phylactolaemate bryozoans. BMC Genomics 2023; 24:711. [PMID: 38001438 PMCID: PMC10675955 DOI: 10.1186/s12864-023-09826-z] [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: 07/20/2023] [Accepted: 11/22/2023] [Indexed: 11/26/2023] Open
Abstract
BACKGROUND Bryozoans are mostly sessile aquatic colonial invertebrates belonging to the clade Lophotrochozoa, which unites many protostome bilaterian phyla such as molluscs, annelids and brachiopods. While Hox and ParaHox genes have been extensively studied in various lophotrochozoan lineages, investigations on Hox and ParaHox gene complements in bryozoans are scarce. RESULTS Herein, we present the most comprehensive survey of Hox and ParaHox gene complements in bryozoans using four genomes and 35 transcriptomes representing all bryozoan clades: Cheilostomata, Ctenostomata, Cyclostomata and Phylactolaemata. Using similarity searches, phylogenetic analyses and detailed manual curation, we have identified five Hox genes in bryozoans (pb, Dfd, Lox5, Lox4 and Post2) and one ParaHox gene (Cdx). Interestingly, we observed lineage-specific duplication of certain Hox and ParaHox genes (Dfd, Lox5 and Cdx) in some bryozoan lineages. CONCLUSIONS The bryozoan Hox cluster does not retain the ancestral lophotrochozoan condition but appears relatively simple (includes only five genes) and broken into two genomic regions, characterized by the loss and duplication of serval genes. Importantly, bryozoans share the lack of two Hox genes (Post1 and Scr) with their proposed sister-taxon, Phoronida, which suggests that those genes were missing in the most common ancestor of bryozoans and phoronids.
Collapse
Affiliation(s)
- Ahmed J Saadi
- Department of Evolutionary Biology, Unit for Integrative Zoology, University of Vienna, Schlachthausgasse 43, Vienna, A-1030, Austria.
| | - André Luiz de Oliveira
- Department of Symbiosis, Max-Planck-Institute for Marine Microbiology, Celsiustraße,1, D-28359, Bremen, Germany
| | - Kevin M Kocot
- Department of Biological Sciences and Alabama Museum of Natural History, University of Alabama, Tuscaloosa, Alabama, 35487, USA
| | - Thomas Schwaha
- Department of Evolutionary Biology, Unit for Integrative Zoology, University of Vienna, Schlachthausgasse 43, Vienna, A-1030, Austria
| |
Collapse
|
2
|
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: 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: 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.
Collapse
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.
| |
Collapse
|
3
|
Kostyuchenko RP, Amosov AV. Spatial Colinear but Broken Temporal Expression of Duplicated ParaHox Genes in Asexually Reproducing Annelids, Nais communis and Pristina longiseta. Genes (Basel) 2023; 14:1501. [PMID: 37510405 PMCID: PMC10379933 DOI: 10.3390/genes14071501] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 07/13/2023] [Accepted: 07/21/2023] [Indexed: 07/30/2023] Open
Abstract
ParaHox genes are key developmental regulators involved in the patterning of the digestive tract along the anteroposterior axis and the development of the nervous system. Most studies have focused on the function of these genes in embryogenesis, while their expression patterns in postembryonic development often remain unknown. In this study, we identified for the first time all ParaHox orthologs in two naidid oligochaetes, N. communis and P. longiseta, and described their expression patterns during normal growth and fission in these animals. We showed that Gsx and Cdx are presented by two paralogs, while Xlox is a single copy gene in both species. Using whole-mount in situ hybridization, we also found that orthologs, except for the Xlox gene, have similar activity patterns with minor differences in details, while the expression patterns of paralogs can differ significantly. However, all these genes are involved in axial patterning and/or in tissue remodeling during growth and asexual reproduction in naidids. Moreover, during paratomic fission, these genes are expressed with spatial colinearity but temporal colinearity is broken. The results of this study may be evidence of the functional diversification of duplicated genes and suggest involvement of the ParaHox genes in whole-body patterning during growth and asexual reproduction in annelids.
Collapse
Affiliation(s)
- Roman P Kostyuchenko
- Department of Embryology, St. Petersburg State University, Universitetskaya nab. 7-9, 199034 St. Petersburg, Russia
| | - Artem V Amosov
- Department of Embryology, St. Petersburg State University, Universitetskaya nab. 7-9, 199034 St. Petersburg, Russia
| |
Collapse
|
4
|
Evidence from oyster suggests an ancient role for Pdx in regulating insulin gene expression in animals. Nat Commun 2021; 12:3117. [PMID: 34035261 PMCID: PMC8149454 DOI: 10.1038/s41467-021-23216-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2018] [Accepted: 04/19/2021] [Indexed: 11/17/2022] Open
Abstract
Hox and ParaHox genes encode transcription factors with similar expression patterns in divergent animals. The Pdx (Xlox) homeobox gene, for example, is expressed in a sharp spatial domain in the endodermal cell layer of the gut in chordates, echinoderms, annelids and molluscs. The significance of comparable gene expression patterns is unclear because it is not known if downstream transcriptional targets are also conserved. Here, we report evidence indicating that a classic transcriptional target of Pdx1 in vertebrates, the insulin gene, is a likely direct target of Pdx in Pacific oyster adults. We show that one insulin-related gene, cgILP, is co-expressed with cgPdx in oyster digestive tissue. Transcriptomic comparison suggests that this tissue plays a similar role to the vertebrate pancreas. Using ATAC-seq and ChIP, we identify an upstream regulatory element of the cgILP gene which shows binding interaction with cgPdx protein in oyster hepatopancreas and demonstrate, using a cell culture assay, that the oyster Pdx can act as a transcriptional activator through this site, possibly in synergy with NeuroD. These data argue that a classic homeodomain-target gene interaction dates back to the origin of Bilateria. In vertebrates insulin is a direct transcriptional target of Pdx: the same is true in Pacific oysters and the authors show insulin-related gene, cgILP, is co-expressed with cgPdx in oyster digestive tissue, showing this gene interaction dates back to the origin of Bilateria.
Collapse
|
5
|
Salamanca-Díaz DA, Calcino AD, de Oliveira AL, Wanninger A. Non-collinear Hox gene expression in bivalves and the evolution of morphological novelties in mollusks. Sci Rep 2021; 11:3575. [PMID: 33574385 PMCID: PMC7878502 DOI: 10.1038/s41598-021-82122-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 01/15/2021] [Indexed: 12/27/2022] Open
Abstract
Hox genes are key developmental regulators that are involved in establishing morphological features during animal ontogeny. They are commonly expressed along the anterior-posterior axis in a staggered, or collinear, fashion. In mollusks, the repertoire of body plans is widely diverse and current data suggest their involvement during development of landmark morphological traits in Conchifera, one of the two major lineages that comprises those taxa that originated from a uni-shelled ancestor (Monoplacophora, Gastropoda, Cephalopoda, Scaphopoda, Bivalvia). For most clades, and bivalves in particular, data on Hox gene expression throughout ontogeny are scarce. We thus investigated Hox expression during development of the quagga mussel, Dreissena rostriformis, to elucidate to which degree they might contribute to specific phenotypic traits as in other conchiferans. The Hox/ParaHox complement of Mollusca typically comprises 14 genes, 13 of which are present in bivalve genomes including Dreissena. We describe here expression of 9 Hox genes and the ParaHox gene Xlox during Dreissena development. Hox expression in Dreissena is first detected in the gastrula stage with widely overlapping expression domains of most genes. In the trochophore stage, Hox gene expression shifts towards more compact, largely mesodermal domains. Only few of these domains can be assigned to specific developing morphological structures such as Hox1 in the shell field and Xlox in the hindgut. We did not find traces of spatial or temporal staggered expression of Hox genes in Dreissena. Our data support the notion that Hox gene expression has been coopted independently, and to varying degrees, into lineage-specific structures in the respective conchiferan clades. The non-collinear mode of Hox expression in Dreissena might be a result of the low degree of body plan regionalization along the bivalve anterior-posterior axis as exemplified by the lack of key morphological traits such as a distinct head, cephalic tentacles, radula apparatus, and a simplified central nervous system.
Collapse
Affiliation(s)
- David A Salamanca-Díaz
- Department of Evolutionary Biology, Unit for Integrative Zoology, University of Vienna, Althanstraße 14, 1090, Vienna, Austria
| | - Andrew D Calcino
- Department of Evolutionary Biology, Unit for Integrative Zoology, University of Vienna, Althanstraße 14, 1090, Vienna, Austria
| | - André L de Oliveira
- Department of Functional and Evolutionary Ecology, Unit for Bio-Oceanography and Marine Biology, University of Vienna, Althantraße 14, 1090, Vienna, Austria
| | - Andreas Wanninger
- Department of Evolutionary Biology, Unit for Integrative Zoology, University of Vienna, Althanstraße 14, 1090, Vienna, Austria.
| |
Collapse
|
6
|
Johnson AB, Lambert JD. The Caudal ParaHox gene is required for hindgut development in the mollusc Tritia (a.k.a. Ilyanassa). Dev Biol 2020; 470:1-9. [PMID: 33191200 DOI: 10.1016/j.ydbio.2020.10.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 10/19/2020] [Accepted: 10/20/2020] [Indexed: 11/26/2022]
Abstract
Caudal homeobox genes are found across animals, typically linked to two other homeobox genes in what has been called the ParaHox cluster. These genes have been proposed to pattern the anterior-posterior axis of the endoderm ancestrally, but the expression of Caudal in extant groups is varied and often occurs in other germ layers. Here we examine the role of Caudal in the embryo of the mollusc Tritia (Ilyanassa) obsoleta. ToCaudal expression is initially broad, then becomes progressively restricted and is finally only in the developing hindgut (a.k.a. intestine). Knockdown of ToCaudal using morpholino oligonucleotides specifically blocks hindgut development, indicating that despite its initially broad expression, the functional role of ToCaudal is in hindgut patterning. This is the first functional characterization of Caudal in an animal with spiralian development, which is an ancient mode of embryogenesis that arose early in bilaterian animal evolution. These results are consistent with the hypothesis that the ancestral role of the ParaHox genes was anterior-posterior patterning of the endoderm.
Collapse
Affiliation(s)
- Adam B Johnson
- Department of Biology, University of Rochester, Rochester, NY, 14627, USA
| | - J David Lambert
- Department of Biology, University of Rochester, Rochester, NY, 14627, USA.
| |
Collapse
|
7
|
Ribeiro RP, Ponz-Segrelles G, Bleidorn C, Aguado MT. Comparative transcriptomics in Syllidae (Annelida) indicates that posterior regeneration and regular growth are comparable, while anterior regeneration is a distinct process. BMC Genomics 2019; 20:855. [PMID: 31726983 PMCID: PMC6854643 DOI: 10.1186/s12864-019-6223-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 10/24/2019] [Indexed: 02/23/2023] Open
Abstract
Background Annelids exhibit remarkable postembryonic developmental abilities. Most annelids grow during their whole life by adding segments through the action of a segment addition zone (SAZ) located in front of the pygidium. In addition, they show an outstanding ability to regenerate their bodies. Experimental evidence and field observations show that many annelids are able to regenerate their posterior bodies, while anterior regeneration is often limited or absent. Syllidae, for instance, usually show high abilities of posterior regeneration, although anterior regeneration varies across species. Some syllids are able to partially restore the anterior end, while others regenerate all lost anterior body after bisection. Here, we used comparative transcriptomics to detect changes in the gene expression profiles during anterior regeneration, posterior regeneration and regular growth of two syllid species: Sphaerosyllis hystrix and Syllis gracilis; which exhibit limited and complete anterior regeneration, respectively. Results We detected a high number of genes with differential expression: 4771 genes in S. hystrix (limited anterior regeneration) and 1997 genes in S. gracilis (complete anterior regeneration). For both species, the comparative transcriptomic analysis showed that gene expression during posterior regeneration and regular growth was very similar, whereas anterior regeneration was characterized by up-regulation of several genes. Among the up-regulated genes, we identified putative homologs of regeneration-related genes associated to cellular proliferation, nervous system development, establishment of body axis, and stem-cellness; such as rup and JNK (in S. hystrix); and glutamine synthetase, elav, slit, Hox genes, β-catenin and PL10 (in S. gracilis). Conclusions Posterior regeneration and regular growth show no significant differences in gene expression in the herein investigated syllids. However, anterior regeneration is associated with a clear change in terms of gene expression in both species. Our comparative transcriptomic analysis was able to detect differential expression of some regeneration-related genes, suggesting that syllids share some features of the regenerative mechanisms already known for other annelids and invertebrates.
Collapse
Affiliation(s)
- Rannyele Passos Ribeiro
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Cantoblanco, 28049, Madrid, Spain.
| | - Guillermo Ponz-Segrelles
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Cantoblanco, 28049, Madrid, Spain
| | - Christoph Bleidorn
- Animal Evolution & Biodiversity, Georg-August-Universität Göttingen, 37073, Göttingen, Germany.,German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, 04103, Leipzig, Germany
| | - Maria Teresa Aguado
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Cantoblanco, 28049, Madrid, Spain. .,Animal Evolution & Biodiversity, Georg-August-Universität Göttingen, 37073, Göttingen, Germany. .,Centro de Investigación en Biodiversidad y Cambio Global (CIBC-UAM), Universidad Autónoma de Madrid, Madrid, 28049, España.
| |
Collapse
|
8
|
Annunziata R, Andrikou C, Perillo M, Cuomo C, Arnone MI. Development and evolution of gut structures: from molecules to function. Cell Tissue Res 2019; 377:445-458. [PMID: 31446445 DOI: 10.1007/s00441-019-03093-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 08/09/2019] [Indexed: 12/13/2022]
Abstract
The emergence of a specialized system for food digestion and nutrient absorption was a crucial innovation for multicellular organisms. Digestive systems with different levels of complexity evolved in different animals, with the endoderm-derived one-way gut of most bilaterians to be the prevailing and more specialized form. While the molecular events regulating the early phases of embryonic tissue specification have been deeply investigated in animals occupying different phylogenetic positions, the mechanisms underlying gut patterning and gut-associated structures differentiation are still mostly obscure. In this review, we describe the main discoveries in gut and gut-associated structures development in echinoderm larvae (mainly for sea urchin and, when available, for sea star) and compare them with existing information in vertebrates. An impressive degree of conservation emerges when comparing the transcription factor toolkits recruited for gut cells and tissue differentiation in animals as diverse as echinoderms and vertebrates, thus suggesting that their function emerged in the deuterostome ancestor.
Collapse
Affiliation(s)
- Rossella Annunziata
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa comunale, 80121, Naples, Italy
| | - Carmen Andrikou
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa comunale, 80121, Naples, Italy
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, 5006, Bergen, Norway
| | - Margherita Perillo
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa comunale, 80121, Naples, Italy
- Department of Molecular and Cell Biology and Biochemistry, Brown University, 185 Meeting St, Providence, RI, 02912, USA
| | - Claudia Cuomo
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa comunale, 80121, Naples, Italy
| | - Maria I Arnone
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa comunale, 80121, Naples, Italy.
| |
Collapse
|
9
|
Kostyuchenko RP, Kozin VV, Filippova NA, Sorokina EV. FoxA expression pattern in two polychaete species, Alitta virens and Platynereis dumerilii: Examination of the conserved key regulator of the gut development from cleavage through larval life, postlarval growth, and regeneration. Dev Dyn 2019; 248:728-743. [PMID: 30566266 DOI: 10.1002/dvdy.7] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 10/23/2018] [Accepted: 11/29/2018] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND foxA orthologs are involved in various processes from embryo patterning to regulation of metabolism. Since foxA conserved role in the development of the gut of errant annelids has never been thoroughly studied, we used a candidate gene approach to unravel the molecular profile of the alimentary canal in two closely related nereid worms with a trochophore-type lecithotrophic larva. RESULTS The character of foxA expression in the two polychaetes was similar but not identical. The genes were successively activated first in blastoporal cells, then in the stomodeum, the midgut, and hindgut primordia, and in the cells of central and peripheral nervous system. Before the start of active feeding of nectochaetes, we observed a short phase of foxA expression in the entire digestive tract. After amputation of posterior segments, foxA expression was established de novo in the new terminal part of the intestine, and then in the developing hindgut and the anus. CONCLUSIONS We discovered an early marker of endoderm formation previously unknown in errant annelids. Its expression dynamics provided valuable insights into the gut development. Comparative analysis of foxA activity suggests its primary role in gastrulation morphogenesis independently of its type and in midgut and foregut specification. Developmental Dynamics 248:728-743, 2019. © 2018 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Roman P Kostyuchenko
- Department of Embryology, St. Petersburg State University, St. Petersburg, Russia
| | - Vitaly V Kozin
- Department of Embryology, St. Petersburg State University, St. Petersburg, Russia
| | - Nadezhda A Filippova
- Department of Embryology, St. Petersburg State University, St. Petersburg, Russia
| | - Ekaterina V Sorokina
- Department of Embryology, St. Petersburg State University, St. Petersburg, Russia
| |
Collapse
|
10
|
Barton-Owen TB, Szabó R, Somorjai IML, Ferrier DEK. A Revised Spiralian Homeobox Gene Classification Incorporating New Polychaete Transcriptomes Reveals a Diverse TALE Class and a Divergent Hox Gene. Genome Biol Evol 2018; 10:2151-2167. [PMID: 29986009 PMCID: PMC6118893 DOI: 10.1093/gbe/evy144] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/06/2018] [Indexed: 11/13/2022] Open
Abstract
The diversity of mechanisms and capacity for regeneration across the Metazoa present an intriguing challenge in evolutionary biology, impacting on the burgeoning field of regenerative medicine. Broad taxonomic sampling is essential to improve our understanding of regeneration, and studies outside of the traditional model organisms have proved extremely informative. Within the historically understudied Spiralia, the Annelida have an impressive variety of tractable regenerative systems. The biomeralizing, blastema-less regeneration of the head appendage (operculum) of the serpulid polychaete keelworm Spirobranchus (formerly Pomatoceros) lamarcki is one such system. To profile potential regulatory mechanisms, we classified the homeobox gene content of opercular regeneration transcriptomes. As a result of retrieving several difficult-to-classify homeobox sequences, we performed an extensive search and phylogenetic analysis of the TALE and PRD-class homeobox gene content of a broad selection of lophotrochozoan genomes. These analyses contribute to our increasing understanding of the diversity, taxonomic extent, rapid evolution, and radical flexibility of these recently discovered homeobox gene radiations. Our expansion and integration of previous nomenclature systems helps to clarify their cryptic orthology. We also describe an unusual divergent S. lamarcki Antp gene, a previously unclassified lophotrochozoan orphan gene family (Lopx), and a number of novel Nk class orphan genes. The expression and potential involvement of many of these lineage- and clade-restricted homeobox genes in S. lamarcki operculum regeneration provides an example of diversity in regenerative mechanisms, as well as significantly improving our understanding of homeobox gene evolution.
Collapse
Affiliation(s)
- Thomas B Barton-Owen
- Gatty Marine Laboratory, The Scottish Oceans Institute, School of Biology, University of St. Andrews, United Kingdom
- The Biomedical Sciences Research Complex, School of Biology, University of St. Andrews, United Kingdom
| | - Réka Szabó
- Gatty Marine Laboratory, The Scottish Oceans Institute, School of Biology, University of St. Andrews, United Kingdom
| | - Ildiko M L Somorjai
- Gatty Marine Laboratory, The Scottish Oceans Institute, School of Biology, University of St. Andrews, United Kingdom
- The Biomedical Sciences Research Complex, School of Biology, University of St. Andrews, United Kingdom
| | - David E K Ferrier
- Gatty Marine Laboratory, The Scottish Oceans Institute, School of Biology, University of St. Andrews, United Kingdom
| |
Collapse
|
11
|
Starunov VV, Voronezhskaya EE, Nezlin LP. Development of the nervous system in Platynereis dumerilii (Nereididae, Annelida). Front Zool 2017; 14:27. [PMID: 28559917 PMCID: PMC5445494 DOI: 10.1186/s12983-017-0211-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 05/09/2017] [Indexed: 12/14/2022] Open
Abstract
Background The structure and development of the nervous system in Lophotrochozoa has long been recognized as one of the most important subjects for phylogenetic and evolutionary discussion. Many recent papers have presented comprehensive data on the structure and development of catecholaminergic, serotonergic and FMRFamidergic parts of the nervous system. However, relatively few papers contain detailed descriptions of the nervous system in Annelida, one of the largest taxa of Lophotrochozoa. The polychaete species Platynereis dumerilii has recently become one of the more popular model animals in evolutionary and developmental biology. The goal of the present study was to provide a detailed description of its neuronal development. The data obtained will contribute to a better understanding of the basic features of neuronal development in polychaetes. Results We have studied the development of the nervous system in P. dumerilii utilizing histo- and immunochemical labelling of catecholamines, serotonin, FMRFamide related peptides, and acetylated tubulin. The first neuron differentiates at the posterior extremity of the protrochophore, reacts to the antibodies against both serotonin and FMRFamide. Then its fibres run forwards along the ventral side. Soon, more neurons appear at the apical extreme, and their basal neurites form the basel structure of the developing brain (cerebral neuropil and circumesophageal connectives). Initial development of the nervous system starts in two rudiments: anterior and posterior. At the nectochaete stage, segmental ganglia start to differentiate in the anterior-to-posterior direction, and the first structures of the stomatogastric and peripheral nervous system appear. All connectives including the unpaired ventral cord develop from initially paired nerves. Conclusions We present a detailed description of Platynereis dumerilii neuronal development based on anti-acetylated tubulin, serotonin, and FMRFamide-like immunostaining as well as catecholamine histofluorescence. The development of the nervous system starts from peripheral pioneer neurons at both the posterior and anterior poles of the larva, and their neurites form a scaffold upon which the adult central nervous system develops. The anterior-to-posterior mode of the ventral ganglia development challenges the primary heteronomy concept. Comparison with the development of Mollusca reveals substantial similarities with early neuronal development in larval Solenogastres. Electronic supplementary material The online version of this article (doi:10.1186/s12983-017-0211-3) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Viktor V Starunov
- Department of Invertebrate Zoology, St-Petersburg State University, St-Petersburg, 199034 Russia.,Zoological Institute Rus, Acad. Sci, St-Petersburg, 199034 Russia
| | | | - Leonid P Nezlin
- Institute of Developmental Biology, Rus. Acad. Sci, Moscow, 119991 Russia
| |
Collapse
|
12
|
Vellutini BC, Martín-Durán JM, Hejnol A. Cleavage modification did not alter blastomere fates during bryozoan evolution. BMC Biol 2017; 15:33. [PMID: 28454545 PMCID: PMC5408385 DOI: 10.1186/s12915-017-0371-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 04/04/2017] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Stereotypic cleavage patterns play a crucial role in cell fate determination by precisely positioning early embryonic blastomeres. Although misplaced cell divisions can alter blastomere fates and cause embryonic defects, cleavage patterns have been modified several times during animal evolution. However, it remains unclear how evolutionary changes in cleavage impact the specification of blastomere fates. Here, we analyze the transition from spiral cleavage - a stereotypic pattern remarkably conserved in many protostomes - to a biradial cleavage pattern, which occurred during the evolution of bryozoans. RESULTS Using 3D-live imaging time-lapse microscopy (4D-microscopy), we characterize the cell lineage, MAPK signaling, and the expression of 16 developmental genes in the bryozoan Membranipora membranacea. We found that the molecular identity and the fates of early bryozoan blastomeres are similar to the putative homologous blastomeres in spiral-cleaving embryos. CONCLUSIONS Our work suggests that bryozoans have retained traits of spiral development, such as the early embryonic fate map, despite the evolution of a novel cleavage geometry. These findings provide additional support that stereotypic cleavage patterns can be modified during evolution without major changes to the molecular identity and fate of embryonic blastomeres.
Collapse
Affiliation(s)
- Bruno C Vellutini
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, 5006, Bergen, Norway
| | - José M Martín-Durán
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, 5006, Bergen, Norway
| | - Andreas Hejnol
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, 5006, Bergen, Norway.
| |
Collapse
|
13
|
Dahms HU, Won EJ, Kim HS, Han J, Park HG, Souissi S, Raisuddin S, Lee JS. Potential of the small cyclopoid copepod Paracyclopina nana as an invertebrate model for ecotoxicity testing. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2016; 180:282-294. [PMID: 27770640 DOI: 10.1016/j.aquatox.2016.10.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 10/13/2016] [Accepted: 10/14/2016] [Indexed: 06/06/2023]
Abstract
Aquatic invertebrates contribute significantly to environmental impact assessment of contaminants in aquatic ecosystems. Much effort has been made to identify viable and ecologically relevant invertebrate test organisms to meet rigorous regulatory requirements. Copepods, which are ecologically important and widely distributed in aquatic organisms, offer a huge opportunity as test organisms for aquatic toxicity testing. They have a major role not only in the transfer of energy in aquatic food chains, but also as a medium of transfer of aquatic pollutants across the tropic levels. In this regard, a supratidal and benthic harpacticoid copepod Tigriopus japonicus Mori (order Harpacticoida) has shown promising characteristics as a test organism in the field of ecotoxicology. Because there is a need to standardize a battery of test organisms from species in different phylogenetic and critical ecosystem positions, it is important to identify another unrelated planktonic species for wider application and comparison. In this regard, the cyclopoid copepod Paracyclopina nana Smirnov (order Cyclopoida) has emerged as a potential test organism to meet such requirements. Like T. japonicus, it has a number of features that make it a candidate worth consideration in such efforts. Recently, the genomics of P. nana has been unraveled. Data on biochemical and molecular responses of P. nana against exposure to environmental chemicals and other stressors have been collected. Recently, sequences and expression profiles of a number of genes in P. nana encoding for heat shock proteins, xenobiotic-metabolizing enzymes, and antioxidants have been reported. These genes serve as potential biomarkers in biomonitoring of environmental pollutants. Moreover, the application of gene expression techniques and the use of its whole transcriptome have allowed evaluation of transcriptional changes in P. nana with the ultimate aim of understanding the mechanisms of action of environmental stressors. Whole-animal bioassays and gene expression studies indicate that P. nana may serve as an excellent tool to evaluate the impact of diverse disturbances in the marine environment. With a better understanding of toxicological mechanisms, ecotoxicologists will be able to understand defense mechanisms against toxicants in copepods. In this review, we illustrate the potential of P. nana as an alternative as well as a complementary invertebrate model organism for risk assessment of aquatic pollutants.
Collapse
Affiliation(s)
- Hans-Uwe Dahms
- Department of Biomedical Science and Environmental Biology, Kaohsiung Medical University, Kaohsiung 80708, Taiwan; Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
| | - Eun-Ji Won
- Department of Biological Science, College of Science, Sungkyunkwan University, Suwon 16419, South Korea
| | - Hui-Su Kim
- Department of Biological Science, College of Science, Sungkyunkwan University, Suwon 16419, South Korea
| | - Jeonghoon Han
- Department of Biological Science, College of Science, Sungkyunkwan University, Suwon 16419, South Korea
| | - Heum Gi Park
- Department of Marine Bioscience, College of Life Sciences, Gangneung-Wonju National University, Gangneung 25457, South Korea
| | - Sami Souissi
- Univ. Lille, CNRS, Univ. Littoral Cote d'Opale, UMR 8187, LOG, Laboratoire d'Océanologie et de Géosciences, 62930 Wimereux, France
| | - Sheikh Raisuddin
- Department of Medical Elementology and Toxicology, Jamia Hamdard, Hamdard University, New Delhi 110062, India
| | - Jae-Seong Lee
- Department of Biological Science, College of Science, Sungkyunkwan University, Suwon 16419, South Korea.
| |
Collapse
|
14
|
Nervous system development in cephalopods: How egg yolk-richness modifies the topology of the mediolateral patterning system. Dev Biol 2016; 415:143-156. [PMID: 27151209 DOI: 10.1016/j.ydbio.2016.04.027] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 04/30/2016] [Accepted: 04/30/2016] [Indexed: 11/22/2022]
Abstract
Cephalopods possess the most complex centralized nervous system among molluscs and the molecular determinants of its development have only begun to be explored. To better understand how evolved their brain and body axes, we studied Sepia officinalis embryos and investigated the expression patterns of neural regionalization genes involved in the mediolateral patterning of the neuroectoderm in model species. SoxB1 expression reveals that the embryonic neuroectoderm is made of several distinct territories that constitute a large part of the animal pole disc. Concentric nkx2.1, pax6/gsx, and pax3/7/msx/pax2/5/8 positive domains subdivide this neuroectoderm. Looking from dorsal to ventral sides, the sequence of these expressions is reminiscent of the mediolateral subdivision in model species, which provides good evidence for "mediolateral patterning" conservation in cephalopods. A specific feature of cephalopod development, however, includes an unconventional orientation to this mediolateral sequence: median markers (like nkx2.1) are unexpectedly expressed at the periphery of the cuttlefish embryo and lateral markers (like Pax3/7) are expressed centrally. As the egg is rich with yolk, the lips of the blastopore (that classically organizes the neural midline) remain unclosed at the lateral side of the animal pole until late stages of organogenesis, therefore reversing the whole embryo topology. These findings confirm - by means of molecular tools - the location of both ventral and dorsal poles in cephalopod embryos.
Collapse
|
15
|
Fritsch M, Wollesen T, Wanninger A. Hox and ParaHox gene expression in early body plan patterning of polyplacophoran mollusks. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2016; 326:89-104. [PMID: 27098677 PMCID: PMC4949717 DOI: 10.1002/jez.b.22671] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 02/29/2016] [Indexed: 11/22/2022]
Abstract
Molecular developmental studies of various bilaterians have shown that the identity of the anteroposterior body axis is controlled by Hox and ParaHox genes. Detailed Hox and ParaHox gene expression data are available for conchiferan mollusks, such as gastropods (snails and slugs) and cephalopods (squids and octopuses), whereas information on the putative conchiferan sister group, Aculifera, is still scarce (but see Fritsch et al., 2015 on Hox gene expression in the polyplacophoran Acanthochitona crinita). In contrast to gastropods and cephalopods, the Hox genes in polyplacophorans are expressed in an anteroposterior sequence similar to the condition in annelids and other bilaterians. Here, we present the expression patterns of the Hox genes Lox5, Lox4, and Lox2, together with the ParaHox gene caudal (Cdx) in the polyplacophoran A. crinita. To localize Hox and ParaHox gene transcription products, we also investigated the expression patterns of the genes FMRF and Elav, and the development of the nervous system. Similar to the other Hox genes, all three Acr‐Lox genes are expressed in an anteroposterior sequence. Transcripts of Acr‐Cdx are seemingly present in the forming hindgut at the posterior end. The expression patterns of both the central class Acr‐Lox genes and the Acr‐Cdx gene are strikingly similar to those in annelids and nemerteans. In Polyplacophora, the expression patterns of the Hox and ParaHox genes seem to be evolutionarily highly conserved, while in conchiferan mollusks these genes are co‐opted into novel functions that might have led to evolutionary novelties, at least in gastropods and cephalopods.
Collapse
Affiliation(s)
- Martin Fritsch
- Department of Integrative Zoology, Faculty of Life Sciences, University of Vienna, Vienna, 1090, Austria
| | - Tim Wollesen
- Department of Integrative Zoology, Faculty of Life Sciences, University of Vienna, Vienna, 1090, Austria
| | - Andreas Wanninger
- Department of Integrative Zoology, Faculty of Life Sciences, University of Vienna, Vienna, 1090, Austria
| |
Collapse
|
16
|
|
17
|
Wollesen T, Rodríguez Monje SV, McDougall C, Degnan BM, Wanninger A. The ParaHox gene Gsx patterns the apical organ and central nervous system but not the foregut in scaphopod and cephalopod mollusks. EvoDevo 2015; 6:41. [PMID: 26715985 PMCID: PMC4693441 DOI: 10.1186/s13227-015-0037-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 12/17/2015] [Indexed: 11/21/2022] Open
Abstract
Background It has been hypothesized that the ParaHox gene Gsx patterned the foregut of the last common bilaterian ancestor. This notion was corroborated by Gsx expression in three out of four lophotrochozoan species, several ecdysozoans, and some deuterostomes. Remarkably, Gsx is also expressed in the bilaterian anterior-most central nervous system (CNS) and the gastropod and annelid apical organ. To infer whether these findings are consistent with other mollusks or even lophotrochozoans, we investigated Gsx expression in developmental stages of representatives of two other molluscan classes, the scaphopod Antalis entalis and the cephalopod Idiosepius notoides. Results Gsx is not expressed in the developing digestive tract of Antalis entalis and Idiosepius notoides. Instead, it is expressed in cells of the apical organ in the scaphopod trochophore and in two cells adjacent to this organ. Late-stage trochophores express Aen-Gsx in cells of the developing cerebral and pedal ganglia and in cells close to the pavilion, mantle, and foot. In postmetamorphic specimens, Aen-Gsx is expressed in the cerebral and pedal ganglia, the foot, and the nascent captacula. In early squid embryos, Ino-Gsx is expressed in the cerebral, palliovisceral, and optic ganglia. In late-stage embryos, Ino-Gsx is additionally expressed close to the eyes and in the supraesophageal and posterior subesophageal masses and optic lobes. Developmental stages close to hatching express Ino-Gsx only close to the eyes. Conclusions Our results suggest that Gsx expression in the foregut might not be a plesiomorphic trait of the Lophotrochozoa as insinuated previously. Since neither ecdysozoans nor deuterostomes express Gsx in their gut, a role in gut formation in the last common bilaterian ancestor appears unlikely. Gsx is consistently expressed in the bilaterian anterior-most CNS and the apical organ of lophotrochozoan larvae, suggesting a recruitment of Gsx into the formation of this organ in the Lophotrochozoa. The cephalopod posterior subesophageal mass and optic ganglia and the scaphopod pedal ganglia also express Gsx. In summary, Gsx expression only appears to be conserved in the anterior-most brain region during evolution. Accordingly, Gsx appears to have been recruited into the formation of other expression domains, e.g., the apical organ or the foregut, in some lophotrochozoans.
Collapse
Affiliation(s)
- Tim Wollesen
- Department of Integrative Zoology, Faculty of Life Sciences, University of Vienna, 1090 Vienna, Austria
| | | | - Carmel McDougall
- School of Biological Sciences, The University of Queensland, Brisbane, QLD 4072 Australia
| | - Bernard M Degnan
- School of Biological Sciences, The University of Queensland, Brisbane, QLD 4072 Australia
| | - Andreas Wanninger
- Department of Integrative Zoology, Faculty of Life Sciences, University of Vienna, 1090 Vienna, Austria
| |
Collapse
|
18
|
Martín-Durán JM, Vellutini BC, Hejnol A. Evolution and development of the adelphophagic, intracapsular Schmidt's larva of the nemertean Lineus ruber. EvoDevo 2015; 6:28. [PMID: 26417429 PMCID: PMC4584431 DOI: 10.1186/s13227-015-0023-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 09/14/2015] [Indexed: 11/22/2022] Open
Abstract
Background The life cycle of many animals includes a larval stage, which has diversified into an astonishing variety of ecological strategies. The Nemertea is a group of spiralians that exhibits a broad diversity of larval forms, including the iconic pilidium. A pelagic planktotrophic pilidium is the ancestral form in the Pilidiophora, but several lineages exhibit deviations of this condition, mostly as a transition to pelagic lecithotrophy. The most extreme case occurs, however, in the Pilidiophoran Lineus ruber, which exhibits an adelphophagic intracapsular pilidium, the so-called Schmidt’s larva. Results We combined confocal laser scanning microscopy and gene expression studies to characterize the development and metamorphosis of the Schmidt’s larva of L. ruber. The larva forms after gastrulation, and comprises a thin epidermis, a proboscis rudiment and two pairs of imaginal discs from which the juvenile will develop. The cells internalized during gastrulation form a blind gut and the blastopore gives rise to the mouth of the larva and juvenile. The Schmidt’s larva eats other siblings that occupy the same egg capsule, accumulating nutrients for the juvenile. A gradual metamorphosis involves the differentiation of the juvenile cell types from the imaginal discs and the shedding of the larval epidermis. The expression of evolutionarily conserved anterior (foxQ2, six3/6, gsc, otx), endomesodermal (foxA, GATA456-a, twi-a) and posterior (evx, cdx) markers demonstrate that the juvenile retains the molecular patterning of the Schmidt’s larva. After metamorphosis, the juveniles stay over 20 days within the egg masses, until they are fully mature and hatch. Conclusions The evolution of the intracapsular Schmidt’s larva involved the loss of the typical feeding structures of the planktotrophic pilidium and a precocious formation of the imaginal discs, as also observed in other pelagic lecithotrophic forms. However, no special adaptations are observed related to adelphophagy. As in planktotrophic pilidium, the molecular mechanism patterning the juvenile is only active in the imaginal discs and not during the early development of the larva, suggesting two separate molecular programs during nemertean embryogenesis. Our results illuminate the diversification of larval forms in the Pilidiophora and Nemertea, and thus on the developmental mechanisms underlying metazoan larval evolution. Electronic supplementary material The online version of this article (doi:10.1186/s13227-015-0023-5) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- José M Martín-Durán
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, 5008 Bergen, Norway
| | - Bruno C Vellutini
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, 5008 Bergen, Norway
| | - Andreas Hejnol
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, 5008 Bergen, Norway
| |
Collapse
|
19
|
|
20
|
Mulley JF, Holland PW. Genomic organisation of the seven ParaHox genes of coelacanths. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B: MOLECULAR AND DEVELOPMENTAL EVOLUTION 2014; 322:352-8. [PMID: 23775937 PMCID: PMC4471637 DOI: 10.1002/jez.b.22513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Revised: 04/25/2013] [Accepted: 04/25/2013] [Indexed: 11/30/2022]
Abstract
Human and mouse genomes contain six ParaHox genes implicated in gut and neural patterning. In coelacanths and cartilaginous fish, an additional ParaHox gene exists—Pdx2—that dates back to the genome duplications in early vertebrate evolution. Here we examine the genomic arrangement and flanking genes of all ParaHox genes in coelacanths, to determine the full complement of these genes. We find that coelacanths have seven ParaHox genes in total, in four chromosomal locations, revealing that five gene losses occurred soon after vertebrate genome duplication. Comparison of intergenic sequences reveals that some Pdx1 regulatory regions associated with development of pancreatic islets are older than tetrapods, that Pdx1 and Pdx2 share few if any conserved non-coding elements, and that there is very high sequence conservation between coelacanth species.
Collapse
Affiliation(s)
- John F. Mulley
- School of Biological SciencesBangor UniversityBangorGwynedd, United Kingdom
| | | |
Collapse
|
21
|
Annunziata R, Martinez P, Arnone MI. Intact cluster and chordate-like expression of ParaHox genes in a sea star. BMC Biol 2013; 11:68. [PMID: 23803323 PMCID: PMC3710244 DOI: 10.1186/1741-7007-11-68] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Accepted: 04/29/2013] [Indexed: 11/19/2022] Open
Abstract
Background The ParaHox genes are thought to be major players in patterning the gut of several bilaterian taxa. Though this is a fundamental role that these transcription factors play, their activities are not limited to the endoderm and extend to both ectodermal and mesodermal tissues. Three genes compose the ParaHox group: Gsx, Xlox and Cdx. In some taxa (mostly chordates but to some degree also in protostomes) the three genes are arranged into a genomic cluster, in a similar fashion to what has been shown for the better-known Hox genes. Sea urchins possess the full complement of ParaHox genes but they are all dispersed throughout the genome, an arrangement that, perhaps, represented the primitive condition for all echinoderms. In order to understand the evolutionary history of this group of genes we cloned and characterized all ParaHox genes, studied their expression patterns and identified their genomic loci in a member of an earlier branching group of echinoderms, the asteroid Patiria miniata. Results We identified the three ParaHox orthologs in the genome of P. miniata. While one of them, PmGsx is provided as maternal message, with no zygotic activation afterwards, the other two, PmLox and PmCdx are expressed during embryogenesis, within restricted domains of both endoderm and ectoderm. Screening of a Patiria bacterial artificial chromosome (BAC) library led to the identification of a clone containing the three genes. The transcriptional directions of PmGsx and PmLox are opposed to that of the PmCdx gene within the cluster. Conclusions The identification of P. miniata ParaHox genes has revealed the fact that these genes are clustered in the genome, in contrast to what has been reported for echinoids. Since the presence of an intact cluster, or at least a partial cluster, has been reported in chordates and polychaetes respectively, it becomes clear that within echinoderms, sea urchins have modified the original bilaterian arrangement. Moreover, the sea star ParaHox domains of expression show chordate-like features not found in the sea urchin, confirming that the dynamics of gene expression for the respective genes and their putative regulatory interactions have clearly changed over evolutionary time within the echinoid lineage.
Collapse
Affiliation(s)
- Rossella Annunziata
- Stazione Zoologica Anton Dohrn di Napoli, Cellular and Developmental Biology, Villa Comunale, 80121 Napoli, Italy
| | | | | |
Collapse
|
22
|
Novikova EL, Bakalenko NI, Nesterenko AY, Kulakova MA. Expression of Hox genes during regeneration of nereid polychaete Alitta (Nereis) virens (Annelida, Lophotrochozoa). EvoDevo 2013; 4:14. [PMID: 23638687 PMCID: PMC3667000 DOI: 10.1186/2041-9139-4-14] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Accepted: 02/05/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Hox genes are the key determinants of different morphogenetic events in all bilaterian animals. These genes are probably responsible for the maintenance of regenerative capacities by providing positional information in the regenerating animal body. Polychaetes are well known for their ability to regenerate the posterior as well as the anterior part of the body. We have recently described the expression of 10 out of 11 Hox genes during postlarval growth of Alitta (Nereis) virens. Hox genes form gradient overlapping expression patterns, which probably do not contribute to the morphological diversity of segments along the anterior-posterior axis of the homonomously segmented worm. We suggest that this gradient expression of Hox genes establishes positional information along the body that can be used to maintain coordinated growth and regeneration. RESULTS We showed that most of the Hox gene expression patterns are reorganized in the central nervous system, segmental ectoderm and mesoderm. The reorganization takes place long before regeneration becomes apparent. The most rapid reorganization was observed for the genes with the largest differences in expression levels in the amputation site and the terminal structures (pygidium and growth zone). Moreover, we revealed the expression of two antisense Hox RNAs (Nvi-antiHox5 and Nvi-antiHox7) demonstrating unique expression patterns during regeneration. CONCLUSIONS Hox genes probably participate in the maintenance and restoration of the positional information in A. virens. During postlarval growth and regeneration, Hox genes do not alter the diversity of segments but provide the positional information along the anterior-posterior axis. The reorganization of at least some Hox gene patterns during regeneration may be regulated by their anti-sense transcripts, providing a rapid response of Hox gene transcripts to positional failure. The capacity of Hox genes to maintain the positional information in the adult body is present in different bilaterian animals (planarias, polychaetes and mammals) and might be an ancestral function inherited from the common evolutionary remote ancestor.
Collapse
Affiliation(s)
- Elena L Novikova
- Department of Embryology, Laboratory of Experimental Embryology, Saint-Petersburg State University, Oranienbaumskoe sh., 2, Petergof, Saint Petersburg, Russia
| | - Nadezhda I Bakalenko
- Department of Embryology, Laboratory of Experimental Embryology, Saint-Petersburg State University, Oranienbaumskoe sh., 2, Petergof, Saint Petersburg, Russia
| | - Alexander Y Nesterenko
- Department of Embryology, Laboratory of Experimental Embryology, Saint-Petersburg State University, Oranienbaumskoe sh., 2, Petergof, Saint Petersburg, Russia
| | - Milana A Kulakova
- Department of Embryology, Laboratory of Experimental Embryology, Saint-Petersburg State University, Oranienbaumskoe sh., 2, Petergof, Saint Petersburg, Russia
| |
Collapse
|
23
|
Bakalenko NI, Novikova EL, Nesterenko AY, Kulakova MA. Hox gene expression during postlarval development of the polychaete Alitta virens. EvoDevo 2013; 4:13. [PMID: 23635090 PMCID: PMC3734159 DOI: 10.1186/2041-9139-4-13] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Accepted: 01/29/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Hox genes are the family of transcription factors that play a key role in the patterning of the anterior-posterior axis of all bilaterian animals. These genes display clustered organization and colinear expression. Expression boundaries of individual Hox genes usually correspond with morphological boundaries of the body. Previously, we studied Hox gene expression during larval development of the polychaete Alitta virens (formerly Nereis virens) and discovered that Hox genes are expressed in nereid larva according to the spatial colinearity principle. Adult Alitta virens consist of multiple morphologically similar segments, which are formed sequentially in the growth zone. Since the worm grows for most of its life, postlarval segments constantly change their position along the anterior-posterior axis. RESULTS We studied the expression dynamics of the Hox cluster during postlarval development of the nereid Alitta virens and found that 8 out of 11 Hox genes are transcribed as wide gene-specific gradients in the ventral nerve cord, ectoderm, and mesoderm. The expression domains constantly shift in accordance with the changing proportions of the growing worm, so expression domains of most Hox genes do not have stable anterior or/and posterior boundaries.In the course of our study, we revealed long antisense RNA (asRNA) for some Hox genes. Expression patterns of two of these genes were analyzed using whole-mount in-situ hybridization. This is the first discovery of antisense RNA for Hox genes in Lophotrochozoa. CONCLUSION Hox gene expression in juvenile A. virens differs significantly from Hox gene expression patterns both in A. virens larva and in other Bilateria.We suppose that the postlarval function of the Hox genes in this polychaete is to establish and maintain positional coordinates in a constantly growing body, as opposed to creating morphological difference between segments.
Collapse
Affiliation(s)
- Nadezhda I Bakalenko
- Department of Embryology, Laboratory of Experimental Embryology, SaintPetersburg State University, Oranienbaumskoe sh., 2. St. Peterhof, Saint Petersburg, Russia
| | - Elena L Novikova
- Department of Embryology, Laboratory of Experimental Embryology, SaintPetersburg State University, Oranienbaumskoe sh., 2. St. Peterhof, Saint Petersburg, Russia
| | - Alexander Y Nesterenko
- Department of Embryology, Laboratory of Experimental Embryology, SaintPetersburg State University, Oranienbaumskoe sh., 2. St. Peterhof, Saint Petersburg, Russia
| | - Milana A Kulakova
- Department of Embryology, Laboratory of Experimental Embryology, SaintPetersburg State University, Oranienbaumskoe sh., 2. St. Peterhof, Saint Petersburg, Russia
| |
Collapse
|
24
|
Mikhailov AT. Russian comparative embryology takes form: a conceptual metamorphosis toward "evo-devo". Evol Dev 2012; 14:9-19. [PMID: 23016970 DOI: 10.1111/j.1525-142x.2011.00518.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
This essay recapitulates major paths followed by the Russian tradition of what we refer to today as evolutionary developmental biology ("evo-devo"). The article addresses several questions regarding the conceptual history of evolutionary embryological thought in its particularly Russian perspective: (1) the assertion by the St. Petersburg academician Wolff regarding the possible connections between environmental modifications during morphogenesis and the "transformation" of species, (2) the discovery of shared "principles" underlying animal development by von Baer, (3) the experimental expression of Baer's principles by Kowalevsky and Mechnikoff, (4) Severtsov's theory of phylembryogenesis, (5) Filatov's approach to the study of evolution using comparative "developmental mechanics", and (6) Shmalgausen's concept of "stabilizing" selection as an attempt to elucidate the evolution of developmental mechanisms. The focus on comparative evolutionary embryology, which was established by Kowalevsky and Mechnikoff, still continues to be popular in present-day "evo-devo" research in Russia.
Collapse
Affiliation(s)
- Alexander T Mikhailov
- Developmental Biology Group, Institute of Health Sciences, University of La Coruña, Campus de Oza, Las Jubias Str. s/n, La Coruña, Spain
| |
Collapse
|
25
|
Pfeifer K, Dorresteijn AWC, Fröbius AC. Activation of Hox genes during caudal regeneration of the polychaete annelid Platynereis dumerilii. Dev Genes Evol 2012; 222:165-79. [PMID: 22569931 DOI: 10.1007/s00427-012-0402-z] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Accepted: 04/18/2012] [Indexed: 12/16/2022]
Abstract
The capability of regenerating posterior segments and pygidial structures is ancestral for annelids and has been lost only a few times within this phylum. As one of the three major segmented taxa, annelids enable us to monitor reconstruction of lost tissues and organs. During regeneration, regional identities have to be imprinted onto the newly formed segments. In this study, we show spatial and temporal localization of expression of nine Hox genes during caudal regeneration of the polychaete annelid Platynereis dumerilii. Hox genes are homeodomain genes encoding transcriptional regulators of axial patterning in bilaterian animals during development. We demonstrate that five Platynereis Hox genes belonging to paralog groups (PG) 1, 4, 5, 6, and 9-14 are expressed in domains of the regenerating nervous system consistent with providing positional information along the anteroposterior axis of the regenerate. We report that expression in regenerating neuromeres is limited to varying subsets of perikarya, called gangliosomes. Four of nine genes analyzed do not appear to be involved in axial patterning. Two genes, Pdu-Hox2 and Pdu-Hox3, are predominantly expressed in the growth zone region. For some Hox genes expression in newly formed coelomic epithelia can be observed. Platynereis Hox genes do not exhibit temporal or spatial colinearity. Although there are some similarities to previously reported expression patterns during larval and postlarval development in Nereididae (Kulakova et al. 2007), expression patterns observed during caudal regeneration also show unique patterns.
Collapse
Affiliation(s)
- Kathrin Pfeifer
- Institut für Allgemeine und Spezielle Zoologie, Abteilung Entwicklungsbiologie, Justus-Liebig-Universität Giessen, Stephanstr.24, 35390, Giessen, Germany
| | | | | |
Collapse
|
26
|
Bakalenko NI, Novikova EL, Kulakova MA. Regulatory evolution, Hox genes, and larvae of bilateral animals. BIOL BULL+ 2012. [DOI: 10.1134/s1062359012020033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
27
|
Altenburger A, Martinez P, Wanninger A. Homeobox gene expression in Brachiopoda: the role of Not and Cdx in bodyplan patterning, neurogenesis, and germ layer specification. Gene Expr Patterns 2011; 11:427-36. [PMID: 21782038 DOI: 10.1016/j.gep.2011.07.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2011] [Revised: 07/01/2011] [Accepted: 07/03/2011] [Indexed: 10/18/2022]
Abstract
The molecular control that underlies brachiopod ontogeny is largely unknown. In order to contribute to this issue we analyzed the expression pattern of two homeobox containing genes, Not and Cdx, during development of the rhynchonelliform (i.e., articulate) brachiopod Terebratalia transversa. Not is a homeobox containing gene that regulates the formation of the notochord in chordates, while Cdx (caudal) is a ParaHox gene involved in the formation of posterior tissues of various animal phyla. The T. transversa homolog, TtrNot, is expressed in the ectoderm from the beginning of gastrulation until completion of larval development, which is marked by a three-lobed body with larval setae. Expression starts at gastrulation in two areas lateral to the blastopore and subsequently extends over the animal pole of the gastrula. With elongation of the gastrula, expression at the animal pole narrows to a small band, whereas the areas lateral to the blastopore shift slightly towards the future anterior region of the larva. Upon formation of the three larval body lobes, TtrNot expressing cells are present only in the posterior part of the apical lobe. Expression ceases entirely at the onset of larval setae formation. TtrNot expression is absent in unfertilized eggs, in embryos prior to gastrulation, and in settled individuals during and after metamorphosis. Comparison with the expression patterns of Not genes in other metazoan phyla suggests an ancestral role for this gene in gastrulation and germ layer (ectoderm) specification with co-opted functions in notochord formation in chordates and left/right determination in ambulacrarians and vertebrates. The caudal ortholog, TtrCdx, is first expressed in the ectoderm of the gastrulating embryo in the posterior region of the blastopore. Its expression stays stable in that domain until the blastopore is closed. Thereafter, the expression is confined to the ventral portion of the mantle lobe in the fully developed larva. No TtrCdx expression is detectable in the juvenile after metamorphosis. This expression of TtrCdx is congruent with findings in other metazoans, where genes belonging to the Cdx/caudal family are predominantly localized in posterior domains during gastrulation. Later in development this gene will play a fundamental role in the formation of posterior tissues.
Collapse
Affiliation(s)
- Andreas Altenburger
- University of Copenhagen, Natural History Museum of Denmark, Zoological Museum, Universitetsparken, Copenhagen Ø, Denmark.
| | | | | |
Collapse
|
28
|
Ikuta T. Evolution of invertebrate deuterostomes and Hox/ParaHox genes. GENOMICS, PROTEOMICS & BIOINFORMATICS 2011; 9:77-96. [PMID: 21802045 PMCID: PMC5054439 DOI: 10.1016/s1672-0229(11)60011-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Accepted: 03/21/2011] [Indexed: 11/10/2022]
Abstract
Transcription factors encoded by Antennapedia-class homeobox genes play crucial roles in controlling development of animals, and are often found clustered in animal genomes. The Hox and ParaHox gene clusters have been regarded as evolutionary sisters and evolved from a putative common ancestral gene complex, the ProtoHox cluster, prior to the divergence of the Cnidaria and Bilateria (bilaterally symmetrical animals). The Deuterostomia is a monophyletic group of animals that belongs to the Bilateria, and a sister group to the Protostomia. The deuterostomes include the vertebrates (to which we belong), invertebrate chordates, hemichordates, echinoderms and possibly xenoturbellids, as well as acoelomorphs. The studies of Hox and ParaHox genes provide insights into the origin and subsequent evolution of the bilaterian animals. Recently, it becomes apparent that among the Hox and ParaHox genes, there are significant variations in organization on the chromosome, expression pattern, and function. In this review, focusing on invertebrate deuterostomes, I first summarize recent findings about Hox and ParaHox genes. Next, citing unsolved issues, I try to provide clues that might allow us to reconstruct the common ancestor of deuterostomes, as well as understand the roles of Hox and ParaHox genes in the development and evolution of deuterostomes.
Collapse
Affiliation(s)
- Tetsuro Ikuta
- Marine Genomics Unit, Okinawa Institute of Science and Technology, Uruma, Japan.
| |
Collapse
|
29
|
Martín-Durán JM, Romero R. Evolutionary implications of morphogenesis and molecular patterning of the blind gut in the planarian Schmidtea polychroa. Dev Biol 2011; 352:164-76. [DOI: 10.1016/j.ydbio.2011.01.032] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2010] [Revised: 01/20/2011] [Accepted: 01/25/2011] [Indexed: 10/18/2022]
|
30
|
Samadi L, Steiner G. Conservation of ParaHox genes' function in patterning of the digestive tract of the marine gastropod Gibbula varia. BMC DEVELOPMENTAL BIOLOGY 2010; 10:74. [PMID: 20624311 PMCID: PMC2913954 DOI: 10.1186/1471-213x-10-74] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Accepted: 07/12/2010] [Indexed: 11/10/2022]
Abstract
BACKGROUND Presence of all three ParaHox genes has been described in deuterostomes and lophotrochozoans, but to date one of these three genes, Xlox has not been reported from any ecdysozoan taxa and both Xlox and Gsx are absent in nematodes. There is evidence that the ParaHox genes were ancestrally a single chromosomal cluster. Colinear expression of the ParaHox genes in anterior, middle, and posterior tissues of several species studied so far suggest that these genes may be responsible for axial patterning of the digestive tract. So far, there are no data on expression of these genes in molluscs. RESULTS We isolated the complete coding sequences of the three Gibbula varia ParaHox genes, and then tested their expression in larval and postlarval development. In Gibbula varia, the ParaHox genes participate in patterning of the digestive tract and are expressed in some cells of the neuroectoderm. The expression of these genes coincides with the gradual formation of the gut in the larva. Gva-Gsx patterns potential neural precursors of cerebral ganglia as well as of the apical sensory organ. During larval development this gene is involved in the formation of the mouth and during postlarval development it is expressed in the precursor cells involved in secretion of the radula, the odontoblasts. Gva-Xolx and Gva-Cdx are involved in gut patterning in the middle and posterior parts of digestive tract, respectively. Both genes are expressed in some ventral neuroectodermal cells; however the expression of Gva-Cdx fades in later larval stages while the expression of Gva-Xolx in these cells persists. CONCLUSIONS In Gibbula varia the ParaHox genes are expressed during anterior-posterior patterning of the digestive system. This colinearity is not easy to spot during early larval stages because the differentiated endothelial cells within the yolk permanently migrate to their destinations in the gut. After torsion, Gsx patterns the mouth and foregut, Xlox the midgut gland or digestive gland, and Cdx the hindgut. ParaHox genes of Gibbula are also expressed during specification of cerebral and ventral neuroectodermal cells. Our results provide additional support for the ancestral complexity of Gsx expression and its ancestral role in mouth patterning in protostomes, which was secondarily lost or simplified in some species.
Collapse
Affiliation(s)
- Leyli Samadi
- Department of Evolutionary Biology, Faculty of Life Sciences, University of Vienna, Vienna, Austria.
| | | |
Collapse
|
31
|
Hejnol A, Martindale MQ. Coordinated spatial and temporal expression of Hox genes during embryogenesis in the acoel Convolutriloba longifissura. BMC Biol 2009; 7:65. [PMID: 19796382 PMCID: PMC2761877 DOI: 10.1186/1741-7007-7-65] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2009] [Accepted: 10/01/2009] [Indexed: 11/16/2022] Open
Abstract
Background Hox genes are critical for patterning the bilaterian anterior-posterior axis. The evolution of their clustered genomic arrangement and ancestral function has been debated since their discovery. As acoels appear to represent the sister group to the remaining Bilateria (Nephrozoa), investigating Hox gene expression will provide an insight into the ancestral features of the Hox genes in metazoan evolution. Results We describe the expression of anterior, central and posterior class Hox genes and the ParaHox ortholog Cdx in the acoel Convolutriloba longifissura. Expression of all three Hox genes begins contemporaneously after gastrulation and then resolves into staggered domains along the anterior-posterior axis, suggesting that the spatial coordination of Hox gene expression was present in the bilaterian ancestor. After early surface ectodermal expression, the anterior and central class genes are expressed in small domains of putative neural precursor cells co-expressing ClSoxB1, suggesting an evolutionary early function of Hox genes in patterning parts of the nervous system. In contrast, the expression of the posterior Hox gene is found in all three germ layers in a much broader posterior region of the embryo. Conclusion Our results suggest that the ancestral set of Hox genes was involved in the anterior-posterior patterning of the nervous system of the last common bilaterian ancestor and were later co-opted for patterning in diverse tissues in the bilaterian radiation. The lack of temporal colinearity of Hox expression in acoels may be due to a loss of genomic clustering in this clade or, alternatively, temporal colinearity may have arisen in conjunction with the expansion of the Hox cluster in the Nephrozoa.
Collapse
Affiliation(s)
- Andreas Hejnol
- Kewalo Marine Laboratory, PBRC, University of Hawaii, 41 Ahui Street, Honolulu, HI 96813, USA.
| | | |
Collapse
|
32
|
Hui JHL, Raible F, Korchagina N, Dray N, Samain S, Magdelenat G, Jubin C, Segurens B, Balavoine G, Arendt D, Ferrier DEK. Features of the ancestral bilaterian inferred from Platynereis dumerilii ParaHox genes. BMC Biol 2009; 7:43. [PMID: 19627570 PMCID: PMC2723086 DOI: 10.1186/1741-7007-7-43] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2009] [Accepted: 07/23/2009] [Indexed: 11/10/2022] Open
Abstract
Background The ParaHox gene cluster is the evolutionary sister to the Hox cluster. Whilst the role of the Hox cluster in patterning the anterior-posterior axis of bilaterian animals is well established, and the organisation of vertebrate Hox clusters is intimately linked to gene regulation, much less is known about the more recently discovered ParaHox cluster. ParaHox gene clustering, and its relationship to expression, has only been described in deuterostomes. Conventional protostome models (Drosophila melanogaster and Caenorhabditis elegans) are secondarily derived with respect to ParaHox genes, suffering gene loss and cluster break-up. Results We provide the first evidence for ParaHox gene clustering from a less-derived protostome animal, the annelid Platynereis dumerilii. Clustering of these genes is thus not a sole preserve of the deuterostome lineage within Bilateria. This protostome ParaHox cluster is not entirely intact however, with Pdu-Cdx being on the opposite end of the same chromosome arm from Pdu-Gsx and Pdu-Xlox. From the genomic sequence around the P. dumerilii ParaHox genes the neighbouring genes are identified, compared with other taxa, and the ancestral arrangement deduced. Conclusion We relate the organisation of the ParaHox genes to their expression, and from comparisons with other taxa hypothesise that a relatively complex pattern of ParaHox gene expression existed in the protostome-deuterostome ancestor, which was secondarily simplified along several invertebrate lineages. Detailed comparisons of the gene content around the ParaHox genes enables the reconstruction of the genome surrounding the ParaHox cluster of the protostome-deuterostome ancestor, which existed over 550 million years ago.
Collapse
Affiliation(s)
- Jerome H L Hui
- Department of Zoology, University of Oxford, Oxford, UK.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
33
|
Fluorescent in situ hybridization reveals multiple expression domains for SpBrn1/2/4 and identifies a unique ectodermal cell type that co-expresses the ParaHox gene SpLox. Gene Expr Patterns 2009; 9:324-8. [DOI: 10.1016/j.gep.2009.02.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2008] [Revised: 02/11/2009] [Accepted: 02/13/2009] [Indexed: 11/19/2022]
|
34
|
Koziol U, Lalanne AI, Castillo E. Hox Genes in the Parasitic Platyhelminthes Mesocestoides corti, Echinococcus multilocularis, and Schistosoma mansoni: Evidence for a Reduced Hox Complement. Biochem Genet 2009; 47:100-16. [DOI: 10.1007/s10528-008-9210-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2008] [Accepted: 08/15/2008] [Indexed: 11/30/2022]
|
35
|
Chiori R, Jager M, Denker E, Wincker P, Da Silva C, Le Guyader H, Manuel M, Quéinnec E. Are Hox genes ancestrally involved in axial patterning? Evidence from the hydrozoan Clytia hemisphaerica (Cnidaria). PLoS One 2009; 4:e4231. [PMID: 19156208 PMCID: PMC2626245 DOI: 10.1371/journal.pone.0004231] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2008] [Accepted: 12/05/2008] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The early evolution and diversification of Hox-related genes in eumetazoans has been the subject of conflicting hypotheses concerning the evolutionary conservation of their role in axial patterning and the pre-bilaterian origin of the Hox and ParaHox clusters. The diversification of Hox/ParaHox genes clearly predates the origin of bilaterians. However, the existence of a "Hox code" predating the cnidarian-bilaterian ancestor and supporting the deep homology of axes is more controversial. This assumption was mainly based on the interpretation of Hox expression data from the sea anemone, but growing evidence from other cnidarian taxa puts into question this hypothesis. METHODOLOGY/PRINCIPAL FINDINGS Hox, ParaHox and Hox-related genes have been investigated here by phylogenetic analysis and in situ hybridisation in Clytia hemisphaerica, an hydrozoan species with medusa and polyp stages alternating in the life cycle. Our phylogenetic analyses do not support an origin of ParaHox and Hox genes by duplication of an ancestral ProtoHox cluster, and reveal a diversification of the cnidarian HOX9-14 genes into three groups called A, B, C. Among the 7 examined genes, only those belonging to the HOX9-14 and the CDX groups exhibit a restricted expression along the oral-aboral axis during development and in the planula larva, while the others are expressed in very specialised areas at the medusa stage. CONCLUSIONS/SIGNIFICANCE Cross species comparison reveals a strong variability of gene expression along the oral-aboral axis and during the life cycle among cnidarian lineages. The most parsimonious interpretation is that the Hox code, collinearity and conservative role along the antero-posterior axis are bilaterian innovations.
Collapse
Affiliation(s)
- Roxane Chiori
- UPMC Univ Paris 06, UMR 7138 CNRS UPMC MNHN IRD, Case 05, Paris, France
| | - Muriel Jager
- UPMC Univ Paris 06, UMR 7138 CNRS UPMC MNHN IRD, Case 05, Paris, France
| | - Elsa Denker
- Sars International Centre for Marine Molecular Biology, Bergen, Norway
| | | | | | - Hervé Le Guyader
- UPMC Univ Paris 06, UMR 7138 CNRS UPMC MNHN IRD, Case 05, Paris, France
| | - Michaël Manuel
- UPMC Univ Paris 06, UMR 7138 CNRS UPMC MNHN IRD, Case 05, Paris, France
| | - Eric Quéinnec
- UPMC Univ Paris 06, UMR 7138 CNRS UPMC MNHN IRD, Case 05, Paris, France
| |
Collapse
|
36
|
Cole AG, Rizzo F, Martinez P, Fernandez-Serra M, Arnone MI. Two ParaHox genes, SpLox and SpCdx, interact to partition the posterior endoderm in the formation of a functional gut. Development 2009; 136:541-9. [PMID: 19144720 DOI: 10.1242/dev.029959] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We report the characterization of the ortholog of the Xenopus XlHbox8 ParaHox gene from the sea urchin Strongylocentrotus purpuratus, SpLox. It is expressed during embryogenesis, first appearing at late gastrulation in the posterior-most region of the endodermal tube, becoming progressively restricted to the constriction between the mid- and hindgut. The physiological effects of the absence of the activity of this gene have been analyzed through knockdown experiments using gene-specific morpholino antisense oligonucleotides. We show that blocking the translation of the SpLox mRNA reduces the capacity of the digestive tract to process food, as well as eliminating the morphological constriction normally present between the mid- and hindgut. Genetic interactions of the SpLox gene are revealed by the analysis of the expression of a set of genes involved in endoderm specification. Two such interactions have been analyzed in more detail: one involving the midgut marker gene Endo16, and another involving the other endodermally expressed ParaHox gene, SpCdx. We find that SpLox is able to bind Endo16 cis-regulatory DNA, suggesting direct repression of Endo16 expression in presumptive hindgut territories. More significantly, we provide the first evidence of interaction between ParaHox genes in establishing hindgut identity, and present a model of gene regulation involving a negative-feedback loop.
Collapse
Affiliation(s)
- Alison G Cole
- Stazione Zoologica Anton Dohrn di Napoli, Villa Comunale, 80121 Napoli, Italy
| | | | | | | | | |
Collapse
|