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Adachi U, Koita R, Seto A, Maeno A, Ishizu A, Oikawa S, Tani T, Ishizaka M, Yamada K, Satoh K, Nakazawa H, Furudate H, Kawakami K, Iwanami N, Matsuda M, Kawamura A. Teleost Hox code defines regional identities competent for the formation of dorsal and anal fins. Proc Natl Acad Sci U S A 2024; 121:e2403809121. [PMID: 38861596 PMCID: PMC11194558 DOI: 10.1073/pnas.2403809121] [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: 02/24/2024] [Accepted: 05/07/2024] [Indexed: 06/13/2024] Open
Abstract
The dorsal and anal fins can vary widely in position and length along the anterior-posterior axis in teleost fishes. However, the molecular mechanisms underlying the diversification of these fins remain unknown. Here, we used genetic approaches in zebrafish and medaka, in which the relative positions of the dorsal and anal fins are opposite, to demonstrate the crucial role of hox genes in the patterning of the teleost posterior body, including the dorsal and anal fins. By the CRISPR-Cas9-induced frameshift mutations and positional cloning of spontaneous dorsalfinless medaka, we show that various hox mutants exhibit the absence of dorsal or anal fins, or a stepwise posterior extension of these fins, with vertebral abnormalities. Our results indicate that multiple hox genes, primarily from hoxc-related clusters, encompass the regions responsible for the dorsal and anal fin formation along the anterior-posterior axis. These results further suggest that shifts in the anterior boundaries of hox expression which vary among fish species, lead to diversification in the position and size of the dorsal and anal fins, similar to how modulations in Hox expression can alter the number of anatomically distinct vertebrae in tetrapods. Furthermore, we show that hox genes responsible for dorsal fin formation are different between zebrafish and medaka. Our results suggest that a novel mechanism has occurred during teleost evolution, in which the gene network responsible for fin formation might have switched to the regulation downstream of other hox genes, leading to the remarkable diversity in the dorsal fin position.
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Affiliation(s)
- Urara Adachi
- Division of Life Science, Graduate School of Science and Engineering, Saitama University, Sakura-ku, Saitama338-8570, Japan
| | - Rina Koita
- Division of Life Science, Graduate School of Science and Engineering, Saitama University, Sakura-ku, Saitama338-8570, Japan
| | - Akira Seto
- Center for Bioscience Research and Education, Utsunomiya University, Utsunomiya321-8505, Japan
| | - Akiteru Maeno
- Cell Architecture Laboratory, National Institute of Genetics, Mishima, Shizuoka411-8540, Japan
| | - Atsuki Ishizu
- Division of Life Science, Graduate School of Science and Engineering, Saitama University, Sakura-ku, Saitama338-8570, Japan
| | - Sae Oikawa
- Division of Life Science, Graduate School of Science and Engineering, Saitama University, Sakura-ku, Saitama338-8570, Japan
| | - Taisei Tani
- Division of Life Science, Graduate School of Science and Engineering, Saitama University, Sakura-ku, Saitama338-8570, Japan
| | - Mizuki Ishizaka
- Division of Life Science, Graduate School of Science and Engineering, Saitama University, Sakura-ku, Saitama338-8570, Japan
| | - Kazuya Yamada
- Division of Life Science, Graduate School of Science and Engineering, Saitama University, Sakura-ku, Saitama338-8570, Japan
| | - Koumi Satoh
- Division of Life Science, Graduate School of Science and Engineering, Saitama University, Sakura-ku, Saitama338-8570, Japan
| | - Hidemichi Nakazawa
- Division of Life Science, Graduate School of Science and Engineering, Saitama University, Sakura-ku, Saitama338-8570, Japan
| | - Hiroyuki Furudate
- Division of Life Science, Graduate School of Science and Engineering, Saitama University, Sakura-ku, Saitama338-8570, Japan
| | - Koichi Kawakami
- Laboratory of Molecular and Developmental Biology, National Institute of Genetics, and Department of Genetics, Graduate University for Advanced Studies (SOKENDAI), Mishima, Shizuoka411-8540, Japan
| | - Norimasa Iwanami
- Center for Bioscience Research and Education, Utsunomiya University, Utsunomiya321-8505, Japan
| | - Masaru Matsuda
- Center for Bioscience Research and Education, Utsunomiya University, Utsunomiya321-8505, Japan
| | - Akinori Kawamura
- Division of Life Science, Graduate School of Science and Engineering, Saitama University, Sakura-ku, Saitama338-8570, Japan
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Orlova SY, Ruzina MN, Emelianova OR, Sergeev AA, Chikurova EA, Orlov AM, Mugue NS. In Search of a Target Gene for a Desirable Phenotype in Aquaculture: Genome Editing of Cyprinidae and Salmonidae Species. Genes (Basel) 2024; 15:726. [PMID: 38927661 PMCID: PMC11202958 DOI: 10.3390/genes15060726] [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: 04/24/2024] [Revised: 05/28/2024] [Accepted: 05/29/2024] [Indexed: 06/28/2024] Open
Abstract
Aquaculture supplies the world food market with a significant amount of valuable protein. Highly productive aquaculture fishes can be derived by utilizing genome-editing methods, and the main problem is to choose a target gene to obtain the desirable phenotype. This paper presents a review of the studies of genome editing for genes controlling body development, growth, pigmentation and sex determination in five key aquaculture Salmonidae and Cyprinidae species, such as rainbow trout (Onchorhynchus mykiss), Atlantic salmon (Salmo salar), common carp (Cyprinus carpio), goldfish (Carassius auratus), Gibel carp (Carassius gibelio) and the model fish zebrafish (Danio rerio). Among the genes studied, the most applicable for aquaculture are mstnba, pomc, and acvr2, the knockout of which leads to enhanced muscle growth; runx2b, mutants of which do not form bones in myoseptae; lepr, whose lack of function makes fish fast-growing; fads2, Δ6abc/5Mt, and Δ6bcMt, affecting the composition of fatty acids in fish meat; dnd mettl3, and wnt4a, mutants of which are sterile; and disease-susceptibility genes prmt7, gab3, gcJAM-A, and cxcr3.2. Schemes for obtaining common carp populations consisting of only large females are promising for use in aquaculture. The immobilized and uncolored zebrafish line is of interest for laboratory use.
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Affiliation(s)
- Svetlana Yu. Orlova
- Laboratory of Molecular Genetics, Russian Federal Research Institute of Fisheries and Oceanography, 105187 Moscow, Russia; (S.Y.O.)
| | - Maria N. Ruzina
- Laboratory of Molecular Genetics, Russian Federal Research Institute of Fisheries and Oceanography, 105187 Moscow, Russia; (S.Y.O.)
| | - Olga R. Emelianova
- Laboratory of Molecular Genetics, Russian Federal Research Institute of Fisheries and Oceanography, 105187 Moscow, Russia; (S.Y.O.)
- Department of Biological Evolution, Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Alexey A. Sergeev
- Laboratory of Molecular Genetics, Russian Federal Research Institute of Fisheries and Oceanography, 105187 Moscow, Russia; (S.Y.O.)
| | - Evgeniya A. Chikurova
- Laboratory of Molecular Genetics, Russian Federal Research Institute of Fisheries and Oceanography, 105187 Moscow, Russia; (S.Y.O.)
| | - Alexei M. Orlov
- Laboratory of Oceanic Ichthyofauna, Shirshov Institute of Oceanology, Russian Academy of Sciences, 117218 Moscow, Russia
- Laboratory of Behavior of Lower Vertebrates, Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, 119071 Moscow, Russia
- Department of Ichthyology, Dagestan State University, 367000 Makhachkala, Russia
| | - Nikolai S. Mugue
- Laboratory of Molecular Genetics, Russian Federal Research Institute of Fisheries and Oceanography, 105187 Moscow, Russia; (S.Y.O.)
- Laboratory of Genome Evolution and Speciation, Institute of Developmental Biology Russian Academy of Sciences, 117808 Moscow, Russia
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Wellik DM. Hox genes and patterning the vertebrate body. Curr Top Dev Biol 2024; 159:1-27. [PMID: 38729674 DOI: 10.1016/bs.ctdb.2024.02.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2024]
Abstract
The diversity of vertebrate body plans is dizzying, yet stunning for the many things they have in common. Vertebrates have inhabited virtually every part of the earth from its coldest to warmest climates. They locomote by swimming, flying, walking, slithering, or climbing, or combinations of these behaviors. And they exist in many different sizes, from the smallest of frogs, fish and lizards to giraffes, elephants, and blue whales. Despite these differences, vertebrates follow a remarkably similar blueprint for the establishment of their body plan. Within the relatively small amount of time required to complete gastrulation, the process through which the three germ layers, ectoderm, mesoderm, and endoderm are created, the embryo also generates its body axis and is simultaneously patterned. For the length of this axis, the genes that distinguish the neck from the rib cage or the trunk from the sacrum are the Hox genes. In vertebrates, there was evolutionary pressure to maintain this set of genes in the organism. Over the past decades, much has been learned regarding the regulatory mechanisms that ensure the appropriate expression of these genes along the main body axes. Genetic functions continue to be explored though much has been learned. Much less has been discerned on the identity of co-factors used by Hox proteins for the specificity of transcriptional regulation or what downstream targets and pathways are critical for patterning events, though there are notable exceptions. Current work in the field is demonstrating that Hox genes continue to function in many organs long after directing early patterning events. It is hopeful continued research will shed light on remaining questions regarding mechanisms used by this important and conserved set of transcriptional regulators.
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Affiliation(s)
- Deneen M Wellik
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, School of Medicine and Public Health, Madison, WI, United States.
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Truong BT, Shull LC, Zepeda BJ, Lencer E, Artinger KB. Human split hand/foot variants are not as functional as wildtype human PRDM1 in the rescue of craniofacial defects. Birth Defects Res 2024; 116:e2327. [PMID: 38456586 PMCID: PMC10949536 DOI: 10.1002/bdr2.2327] [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: 05/19/2023] [Revised: 01/24/2024] [Accepted: 02/21/2024] [Indexed: 03/09/2024]
Abstract
BACKGROUND Split hand/foot malformation (SHFM) is a congenital limb disorder presenting with limb anomalies, such as missing, hypoplastic, or fused digits, and often craniofacial defects, including a cleft lip/palate, microdontia, micrognathia, or maxillary hypoplasia. We previously identified three novel variants in the transcription factor, PRDM1, that are associated with SHFM phenotypes. One individual also presented with a high arch palate. Studies in vertebrates indicate that PRDM1 is important for development of the skull; however, prior to our study, human variants in PRDM1 had not been associated with craniofacial anomalies. METHODS Using transient mRNA overexpression assays in prdm1a-/- mutant zebrafish, we tested whether the PRDM1 SHFM variants were functional and could lead to a rescue of the craniofacial defects observed in prdm1a-/- mutants. We also mined previously published CUT&RUN and RNA-seq datasets that sorted EGFP-positive cells from a Tg(Mmu:Prx1-EGFP) transgenic line that labels the pectoral fin, pharyngeal arches, and dorsal part of the head to examine Prdm1a binding and the effect of Prdm1a loss on craniofacial genes. RESULTS The prdm1a-/- mutants exhibit craniofacial defects including a hypoplastic neurocranium, a loss of posterior ceratobranchial arches, a shorter palatoquadrate, and an inverted ceratohyal. Injection of wildtype (WT) hPRDM1 in prdm1a-/- mutants partially rescues the palatoquadrate phenotype. However, injection of each of the three SHFM variants fails to rescue this skeletal defect. Loss of prdm1a leads to a decreased expression of important craniofacial genes by RNA-seq, including emilin3a, confirmed by hybridization chain reaction expression. Other genes including dlx5a/dlx6a, hand2, sox9b, col2a1a, and hoxb genes are also reduced. Validation by real-time quantitative PCR in the anterior half of zebrafish embryos failed to confirm the expression changes suggesting that the differences are enriched in prx1 expressing cells. CONCLUSION These data suggest that the three SHFM variants are likely not functional and may be associated with the craniofacial defects observed in the humans. Finally, they demonstrate how Prdm1a can directly bind and regulate genes involved in craniofacial development.
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Affiliation(s)
- Brittany T Truong
- Human Medical Genetics & Genomics Graduate Program, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado, USA
- Department of Craniofacial Development, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado, USA
| | - Lomeli C Shull
- Department of Craniofacial Development, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado, USA
| | - Bryan J Zepeda
- Department of Diagnostic and Biological Sciences, University of Minnesota School of Dentistry, Minneapolis, Minnesota, USA
| | - Ezra Lencer
- Biology Department, Lafayette College, Easton, Pennsylvania, USA
| | - Kristin B Artinger
- Department of Craniofacial Development, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado, USA
- Department of Diagnostic and Biological Sciences, University of Minnesota School of Dentistry, Minneapolis, Minnesota, USA
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Ehemann NR, Meyer A, Hulsey CD. Morphological description of spontaneous pelvic fin loss in a neotropical cichlid fish. J Morphol 2024; 285:e21663. [PMID: 38100744 DOI: 10.1002/jmor.21663] [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: 10/03/2023] [Revised: 11/29/2023] [Accepted: 12/01/2023] [Indexed: 12/17/2023]
Abstract
Pelvic fins are a characteristic structure of the vertebrate Bauplan. Yet, pelvic fin loss has occurred repeatedly across a wide diversity of other lineages of tetrapods and at least 48 times in teleost fishes. This pelvic finless condition is often associated with other morphological features such as body elongation, loss of additional structures, and bilateral asymmetry. However, despite the remarkable diversity in the several thousand cichlid fish species, none of them are characterized by the complete absence of pelvic fins. Here, we examined the musculoskeletal structure and associated bilateral asymmetry in Midas cichlids (Amphilophus cf. citrinellus) that lost their pelvic fins spontaneously in the laboratory. Due to this apparent mutational loss of the pelvic girdle and fins, the external and internal anatomy are described in a series of "normal" Midas individuals and their pelvic finless sibling tankmates. First, other traits associated with teleost pelvic fin loss, the genetic basis of pelvic fin loss, and the potential for pleiotropic effects of these genes on other traits in teleosts were all reviewed. Using these traits as a guide, we investigated whether other morphological differences were associated with the pelvic girdle/fin loss. The mean values of the masses of muscle of the pectoral fin, fin ray numbers in the unpaired fins, and oral jaw tooth numbers did not differ between the two pelvic fin morphotypes. However, significant differences in meristic values of the paired traits assessed were observed for the same side of the body between morphotypes. Notably, bilateral asymmetry was found exclusively for the posterior lateral line scales. Finally, we found limited evidence of pleiotropic effects, such as lateral line scale numbers and fluctuating asymmetry between the Midas pelvic fin morphotypes. The fast and relatively isolated changes in the Midas cichlids suggest minor but interesting pleiotropic effects could accompany loss of cichlid pelvic fins.
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Affiliation(s)
| | - Axel Meyer
- Department of Biology, University of Konstanz, Konstanz, Germany
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Tran MH, Nguyen TVA, Do HG, Kieu TK, Nguyen TKT, Le HD, Guerrero-Limon G, Massoz L, Nivelle R, Zappia J, Pham HT, Nguyen LT, Muller M. Testing biological actions of medicinal plants from northern Vietnam on zebrafish embryos and larvae: Developmental, behavioral, and putative therapeutical effects. PLoS One 2023; 18:e0294048. [PMID: 37934745 PMCID: PMC10629648 DOI: 10.1371/journal.pone.0294048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 10/13/2023] [Indexed: 11/09/2023] Open
Abstract
Evaluating the risks and benefits of using traditional medicinal plants is of utmost importance for a huge fraction of the human population, in particular in Northern Vietnam. Zebrafish are increasingly used as a simple vertebrate model for testing toxic and physiological effects of compounds, especially on development. Here, we tested 12 ethanolic extracts from popular medicinal plants collected in northern Vietnam for their effects on zebrafish survival and development during the first 4 days after fertilization. We characterized more in detail their effects on epiboly, hatching, growth, necrosis, body curvature, angiogenesis, skeletal development and mostly increased movement behavior. Finally, we confirm the effect on epiboly caused by the Mahonia bealei extract by staining the actin filaments and performing whole genome gene expression analysis. Further, we show that this extract also inhibits cell migration of mouse embryo fibroblasts. Finally, we analyzed the chemical composition of the Mahonia bealei extract and test the effects of its major components. In conclusion, we show that traditional medicinal plant extracts are able to affect zebrafish early life stage development to various degrees. In addition, we show that an extract causing delay in epiboly also inhibits mammalian cell migration, suggesting that this effect may serve as a preliminary test for identifying extracts that inhibit cancer metastasis.
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Affiliation(s)
- My Hanh Tran
- Laboratory for Organogenesis and Regeneration, GIGA I3, Université de Liège, Liège, Belgium
- Department of Microbiology, Vietnam National University of Science, Faculty of Biology, Hanoi, Vietnam
| | - Thi Van Anh Nguyen
- Department of Microbiology, Vietnam National University of Science, Faculty of Biology, Hanoi, Vietnam
| | - Hoang Giang Do
- Center for Research and Technology Transfer, Vietnam Academy of Science and Technology, Hanoi, Vietnam
| | - Trung Kien Kieu
- GREENLAB, Center for Life Science Research (CELIFE), Vietnam National University of Science, Faculty of Biology, Hanoi, Vietnam
| | - Thi Kim Thanh Nguyen
- Department of Plant Science, Vietnam National University of Science, Faculty of Biology, Hanoi, Vietnam
| | - Hong Diep Le
- Department of Plant Science, Vietnam National University of Science, Faculty of Biology, Hanoi, Vietnam
| | - Gustavo Guerrero-Limon
- Laboratory for Organogenesis and Regeneration, GIGA I3, Université de Liège, Liège, Belgium
| | - Laura Massoz
- Zebrafish Development and Disease Model laboratory, GIGA Stem cells, Université de Liège, Liège, Belgium
| | - Renaud Nivelle
- Laboratory for Organogenesis and Regeneration, GIGA I3, Université de Liège, Liège, Belgium
| | - Jérémie Zappia
- Laboratory for Organogenesis and Regeneration, GIGA I3, Université de Liège, Liège, Belgium
| | - Hai The Pham
- Department of Microbiology, Vietnam National University of Science, Faculty of Biology, Hanoi, Vietnam
- GREENLAB, Center for Life Science Research (CELIFE), Vietnam National University of Science, Faculty of Biology, Hanoi, Vietnam
| | - Lai Thanh Nguyen
- GREENLAB, Center for Life Science Research (CELIFE), Vietnam National University of Science, Faculty of Biology, Hanoi, Vietnam
| | - Marc Muller
- Laboratory for Organogenesis and Regeneration, GIGA I3, Université de Liège, Liège, Belgium
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Hawkins MR, Wingert RA. Zebrafish as a Model to Study Retinoic Acid Signaling in Development and Disease. Biomedicines 2023; 11:biomedicines11041180. [PMID: 37189798 DOI: 10.3390/biomedicines11041180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 04/06/2023] [Accepted: 04/13/2023] [Indexed: 05/17/2023] Open
Abstract
Retinoic acid (RA) is a metabolite of vitamin A (retinol) that plays various roles in development to influence differentiation, patterning, and organogenesis. RA also serves as a crucial homeostatic regulator in adult tissues. The role of RA and its associated pathways are well conserved from zebrafish to humans in both development and disease. This makes the zebrafish a natural model for further interrogation into the functions of RA and RA-associated maladies for the sake of basic research, as well as human health. In this review, we explore both foundational and recent studies using zebrafish as a translational model for investigating RA from the molecular to the organismal scale.
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Affiliation(s)
- Matthew R Hawkins
- Department of Biological Sciences, Center for Stem Cells and Regenerative Medicine, Center for Zebrafish Research, Boler-Parseghian Center for Rare and Neglected Diseases, Warren Center for Drug Discovery, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Rebecca A Wingert
- Department of Biological Sciences, Center for Stem Cells and Regenerative Medicine, Center for Zebrafish Research, Boler-Parseghian Center for Rare and Neglected Diseases, Warren Center for Drug Discovery, University of Notre Dame, Notre Dame, IN 46556, USA
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8
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Abstract
Hox genes encode evolutionarily conserved transcription factors that are essential for the proper development of bilaterian organisms. Hox genes are unique because they are spatially and temporally regulated during development in a manner that is dictated by their tightly linked genomic organization. Although their genetic function during embryonic development has been interrogated, less is known about how these transcription factors regulate downstream genes to direct morphogenetic events. Moreover, the continued expression and function of Hox genes at postnatal and adult stages highlights crucial roles for these genes throughout the life of an organism. Here, we provide an overview of Hox genes, highlighting their evolutionary history, their unique genomic organization and how this impacts the regulation of their expression, what is known about their protein structure, and their deployment in development and beyond.
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Affiliation(s)
- Katharine A. Hubert
- Program in Genetics, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
- Department of Cell and Regenerative Biology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
| | - Deneen M. Wellik
- Department of Cell and Regenerative Biology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
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Mendizábal-Castillero M, Merlo MA, Cross I, Rodríguez ME, Rebordinos L. Genomic Characterization of hox Genes in Senegalese Sole ( Solea senegalensis, Kaup 1858): Clues to Evolutionary Path in Pleuronectiformes. Animals (Basel) 2022; 12:ani12243586. [PMID: 36552509 PMCID: PMC9774920 DOI: 10.3390/ani12243586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 12/12/2022] [Accepted: 12/15/2022] [Indexed: 12/23/2022] Open
Abstract
The Senegalese sole (Solea senegalensis, Kaup 1858), a marine flatfish, belongs to the Pleuronectiformes order. It is a commercially important species for fisheries and aquaculture. However, in aquaculture, several production bottlenecks have still to be resolved, including skeletal deformities and high mortality during the larval and juvenile phase. The study aims to characterize the hox gene clusters in S. senegalensis to understand better the developmental and metamorphosis process in this species. Using a BAC library, the clones that contain hox genes were isolated, sequenced by NGS and used as BAC-FISH probes. Subsequently the hox clusters were studied by sequence analysis, comparative genomics, and cytogenetic and phylogenetic analysis. Cytogenetic analysis demonstrated the localization of four BAC clones on chromosome pairs 4, 12, 13, and 16 of the Senegalese sole cytogenomic map. Comparative and phylogenetic analysis showed a highly conserved organization in each cluster and different phylogenetic clustering in each hox cluster. Analysis of structural and repetitive sequences revealed accumulations of polymorphisms mediated by repetitive elements in the hoxba cluster, mainly retroelements. Therefore, a possible loss of the hoxb7a gene can be established in the Pleuronectiformes lineage. This work allows the organization and regulation of hox clusters to be understood, and is a good base for further studies of expression patterns.
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Peterson KJ, Beavan A, Chabot PJ, McPeek MA, Pisani D, Fromm B, Simakov O. MicroRNAs as Indicators into the Causes and Consequences of Whole-Genome Duplication Events. Mol Biol Evol 2022; 39:msab344. [PMID: 34865078 PMCID: PMC8789304 DOI: 10.1093/molbev/msab344] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Whole-genome duplications (WGDs) have long been considered the causal mechanism underlying dramatic increases to morphological complexity due to the neo-functionalization of paralogs generated during these events. Nonetheless, an alternative hypothesis suggests that behind the retention of most paralogs is not neo-functionalization, but instead the degree of the inter-connectivity of the intended gene product, as well as the mode of the WGD itself. Here, we explore both the causes and consequences of WGD by examining the distribution, expression, and molecular evolution of microRNAs (miRNAs) in both gnathostome vertebrates as well as chelicerate arthropods. We find that although the number of miRNA paralogs tracks the number of WGDs experienced within the lineage, few of these paralogs experienced changes to the seed sequence, and thus are functionally equivalent relative to their mRNA targets. Nonetheless, in gnathostomes, although the retention of paralogs following the 1R autotetraploidization event is similar across the two subgenomes, the paralogs generated by the gnathostome 2R allotetraploidization event are retained in higher numbers on one subgenome relative to the second, with the miRNAs found on the preferred subgenome showing both higher expression of mature miRNA transcripts and slower molecular evolution of the precursor miRNA sequences. Importantly, WGDs do not result in the creation of miRNA novelty, nor do WGDs correlate to increases in complexity. Instead, it is the number of miRNA seed sequences in the genome itself that not only better correlate to instances in complexification, but also mechanistically explain why complexity increases when new miRNA families are established.
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Affiliation(s)
- Kevin J Peterson
- Department of Biological Sciences, Dartmouth College, Hanover, NH, USA
| | - Alan Beavan
- School of Earth Sciences, University of Bristol, Bristol, United Kingdom
- School of Biological Sciences, University of Bristol, Bristol, United Kingdom
| | - Peter J Chabot
- Department of Biological Sciences, Dartmouth College, Hanover, NH, USA
| | - Mark A McPeek
- Department of Biological Sciences, Dartmouth College, Hanover, NH, USA
| | - Davide Pisani
- School of Earth Sciences, University of Bristol, Bristol, United Kingdom
- School of Biological Sciences, University of Bristol, Bristol, United Kingdom
| | - Bastian Fromm
- Arctic University Museum of Norway, UiT, The Arctic University of Norway, Tromsø, Norway
| | - Oleg Simakov
- Department of Neuroscience and Developmental Biology, University of Vienna, Vienna, Austria
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Hajirnis N, Mishra RK. Homeotic Genes: Clustering, Modularity, and Diversity. Front Cell Dev Biol 2021; 9:718308. [PMID: 34458272 PMCID: PMC8386295 DOI: 10.3389/fcell.2021.718308] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 07/22/2021] [Indexed: 11/13/2022] Open
Abstract
Hox genes code for transcription factors and are evolutionarily conserved. They regulate a plethora of downstream targets to define the anterior-posterior (AP) body axis of a developing bilaterian embryo. Early work suggested a possible role of clustering and ordering of Hox to regulate their expression in a spatially restricted manner along the AP axis. However, the recent availability of many genome assemblies for different organisms uncovered several examples that defy this constraint. With recent advancements in genomics, the current review discusses the arrangement of Hox in various organisms. Further, we revisit their discovery and regulation in Drosophila melanogaster. We also review their regulation in different arthropods and vertebrates, with a significant focus on Hox expression in the crustacean Parahyale hawaiensis. It is noteworthy that subtle changes in the levels of Hox gene expression can contribute to the development of novel features in an organism. We, therefore, delve into the distinct regulation of these genes during primary axis formation, segment identity, and extra-embryonic roles such as in the formation of hair follicles or misregulation leading to cancer. Toward the end of each section, we emphasize the possibilities of several experiments involving various organisms, owing to the advancements in the field of genomics and CRISPR-based genome engineering. Overall, we present a holistic view of the functioning of Hox in the animal world.
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Affiliation(s)
- Nikhil Hajirnis
- CSIR – Centre for Cellular and Molecular Biology (CCMB), Hyderabad, India
| | - Rakesh K. Mishra
- CSIR – Centre for Cellular and Molecular Biology (CCMB), Hyderabad, India
- AcSIR – Academy of Scientific and Innovative Research, Ghaziabad, India
- Tata Institute for Genetics and Society (TIGS), Bangalore, India
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