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1.
Artigo em Inglês | MEDLINE | ID: mdl-33689235

RESUMO

The notochord functions primarily as a supporting tissue to maintain the anteroposterior axis of primitive chordates, a function that is replaced entirely by the vertebral column in many vertebrates. The notochord still appears during vertebrate embryogenesis and plays a crucial role in the developmental pattern formation of surrounding structures, such as the somites and neural tube, providing the basis for the vertebrate body plan. The indispensable role of the notochord has often been referred to as the developmental burden and used to explain the evolutionary conservation of notochord; however, the existence of this burden has not been successfully exemplified so far. Since the adaptive value of target tissues appears to result in the evolutionary conservation of upstream structures through the developmental burden, we performed comparative gene expression profiling of the notochord, somites, and neural tube during the mid-embryonic stages in turtles and chicken to measure their evolutionary conservation. When compared with the somites and neural tube, overall gene expression profiles in the notochord showed significantly lower or merely comparable levels of conservation. However, genes involved in inductive signalings, such as the sonic hedgehog (Shh) cascade and the formation of functional primary cilia, showed relatively higher levels of conservation in all the three structures analyzed. Collectively, these results suggest that shh signals are critical as the inductive source and receiving structures, possibly constituting the inter-dependencies of developmental burden.

2.
EMBO Mol Med ; 13(4): e12574, 2021 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-33656268

RESUMO

Genomic defects with large effect size can help elucidate unknown pathologic architecture of mental disorders. We previously reported on a patient with schizophrenia and a balanced translocation between chromosomes 4 and 13 and found that the breakpoint within chromosome 4 is located near the LDB2 gene. We show here that Ldb2 knockout (KO) mice displayed multiple deficits relevant to mental disorders. In particular, Ldb2 KO mice exhibited deficits in the fear-conditioning paradigm. Analysis of the amygdala suggested that dysregulation of synaptic activities controlled by the immediate early gene Arc is involved in the phenotypes. We show that LDB2 forms protein complexes with known transcription factors. Consistently, ChIP-seq analyses indicated that LDB2 binds to > 10,000 genomic sites in human neurospheres. We found that many of those sites, including the promoter region of ARC, are occupied by EGR transcription factors. Our previous study showed an association of the EGR family genes with schizophrenia. Collectively, the findings suggest that dysregulation in the gene expression controlled by the LDB2-EGR axis underlies a pathogenesis of subset of mental disorders.

3.
Elife ; 102021 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-33560225

RESUMO

How genetic changes are linked to morphological novelties and developmental constraints remains elusive. Here, we investigate genetic apparatuses that distinguish fish fins from tetrapod limbs by analyzing transcriptomes and open-chromatin regions (OCRs). Specifically, we compared mouse forelimb buds with the pectoral fin buds of an elasmobranch, the brown-banded bamboo shark (Chiloscyllium punctatum). A transcriptomic comparison with an accurate orthology map revealed both a mass heterochrony and hourglass-shaped conservation of gene expression between fins and limbs. Furthermore, open-chromatin analysis suggested that access to conserved regulatory sequences is transiently increased during mid-stage limb development. During this stage, stage-specific and tissue-specific OCRs were also enriched. Together, early and late stages of fin/limb development are more permissive to mutations than middle stages, which may have contributed to major morphological changes during the fin-to-limb evolution. We hypothesize that the middle stages are constrained by regulatory complexity that results from dynamic and tissue-specific transcriptional controls.

4.
Mol Ecol ; 2020 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-33305470

RESUMO

Factors ranging from ecological opportunity to genome composition might explain why only some lineages form adaptive radiations. While being rare, particular systems can provide natural experiments within an identical ecological setting where the factors promoting increased species numbers and phenotypic divergence in two closely related lineages is notably different. We investigated one such natural experiment using two de novo assembled and 40 resequenced genomes and asked why two closely related Neotropical cichlid fish lineages, the Amphilophus citrinellus species complex (Midas cichlids; radiating) and Archocentrus centrarchus (Flyer cichlid; non-radiating), have resulted in such disparate evolutionary outcomes. Although both lineages inhabit many of the same Nicaraguan lakes, whole-genome inferred demography suggests that priority effects are not likely to be the only cause of the dissimilarities. Also, genome-wide levels of selection, transposable element dynamics, gene family expansion, major chromosomal rearrangements, and the number of genes under positive selection were not markedly different between the two lineages. To more finely investigate particular subsets of the genome that have undergone adaptive divergence in Midas cichlids, we also examined if there was evidence for "molecular pre-adaptation" in regions identified by QTL mapping of repeatedly diverging adaptive traits. Although most of our analyses failed to pinpoint substantial genomic differences, we did identify functional categories containing many genes under positive selection that provide candidates for future studies on the propensity of Midas cichlids to radiate. Our results point to a disproportionate role of local, rather than genome-wide factors underlying the propensity for these cichlid fishes to adaptively radiate.

5.
Commun Biol ; 3(1): 652, 2020 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-33159152

RESUMO

Karyotyping, traditionally performed using cytogenetic techniques, is indispensable for validating genome assemblies whose sequence lengths can be scaled up to chromosome sizes using modern methods. Karyotype reports of chondrichthyans are scarce because of the difficulty in cell culture. Here, we focused on carpet shark species and the culture conditions for fibroblasts and lymphocytes. The utility of the cultured cells enabled the high-fidelity characterization of their karyotypes, namely 2n = 102 for the whale shark (Rhincodon typus) and zebra shark (Stegostoma fasciatum), and 2n = 106 for the brownbanded bamboo shark (Chiloscyllium punctatum) and whitespotted bamboo shark (C. plagiosum). We identified heteromorphic XX/XY sex chromosomes for the two latter species and demonstrated the first-ever fluorescence in situ hybridization of shark chromosomes prepared from cultured cells. Our protocols are applicable to diverse chondrichthyan species and will deepen the understanding of early vertebrate evolution at the molecular level.

6.
J Evol Biol ; 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-33135271

RESUMO

Vision of sharks embraces various biological and ecological themes ranging from predation and adaptation to deep-sea life. However, behavioural and genetic studies have been limited by their elusive lifestyles, repeatedly reported declines of wild populations, and their unique life-history traits including low fecundity and enhanced longevity. Sharks have also not been actively studied on the cellular and molecular levels, because of additional difficulties in cell culture, tissue collection and genome sequencing. A recent study circumvented some of these obstacles by means of genome informatics thereby portrayed the variation of visual opsin gene repertoires among elasmobranchs (sharks and rays) and spectral shifts of the rhodopsin pigment. Comprehensive surveys in whole-genome sequences are also revealing the repertoires of nonvisual opsins with unknown functions. This review is aimed to summarize existing studies on shark opsins with an emphasis on genomic investigation of gene repertoires and to provide insights into the better understanding of underwater ecology of marine megafauna with in vitro experimentation.

7.
Vis Neurosci ; 37: E009, 2020 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-33028447
8.
Zoolog Sci ; 37(5): 458-466, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32972087

RESUMO

Batoidea (rays and skates) is a monophyletic subgroup of elasmobranchs that diverged from the common ancestor with Selachii (sharks) about 270 Mya. A larger number of batoids can adapt to low-salinity environments, in contrast to sharks, which are mostly stenohaline marine species. Among osmoregulatory organs of elasmobranchs, the kidney is known to be dedicated to urea retention in ureosmotic cartilaginous fishes. However, we know little regarding urea reabsorbing mechanisms in the kidney of batoids. Here, we performed physiological and histological investigations on the nephrons in the red stingray (Hemitrygon akajei) and two shark species. We found that the urine/plasma ratios of salt and urea concentrations in the stingray are significantly lower than those in cloudy catshark (Scyliorhinus torazame) under natural seawater, indicating that the kidney of stingray more strongly reabsorbs these osmolytes. By comparing the three-dimensional images of nephrons between stingray and banded houndshark (Triakis scyllium), we showed that the tubular bundle of stingray has a more compact configuration. In the compact tubular bundle of stingray kidney, the distal diluting tubule was highly developed and frequently coiled around the proximal and collecting tubules. Furthermore, co-expression of NKAα1 (Na+/K +-ATPase) and NKCC2 (Na+- K+-2Cl- cotransporter 2) mRNAs was prominent in the coiled diluting segment. These findings imply that NaCl reabsorption is greatly facilitated in the stingray kidney, resulting in a higher reabsorption rate of urea. Lowering the loss of osmolytes in the glomerular filtrate is likely favorable to the adaptability of batoids to a wide range of environmental salinity.

9.
Sci Rep ; 10(1): 14629, 2020 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-32884037

RESUMO

The nuclear protein CCCTC-binding factor (CTCF) contributes as an insulator to chromatin organization in diverse animals. The gene encoding this protein has a paralog which was first identified to be expressed exclusively in the testis in mammals and designated as CTCFL (also called BORIS). CTCFL orthologs were reported only among amniotes, and thus CTCFL was once thought to have arisen in the amniote lineage. In this study, we identified elasmobranch CTCFL orthologs, and investigated its origin with the aid of a shark genome assembly improved by proximity-guided scaffolding. Our analysis employing evolutionary interpretation of syntenic gene location suggested an earlier timing of the gene duplication between CTCF and CTCFL than previously thought, that is, around the common ancestor of extant vertebrates. Also, our transcriptomic sequencing revealed a biased expression of the catshark CTCFL in the testis, suggesting the origin of the tissue-specific localization in mammals more than 400 million years ago. To understand the historical process of the functional consolidation of the long-standing chromatin regulator CTCF, its additional paralogs remaining in some of the descendant lineages for spatially restricted transcript distribution should be taken into consideration.

10.
PLoS One ; 15(7): e0235748, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32701977

RESUMO

With advances in sequencing technology, a vast amount of genomic sequence information has become available. However, annotating biological functions particularly of non-protein-coding regions in genome sequences without experiments is still a challenging task. Recently deep learning-based methods were shown to have the ability to predict gene regulatory regions from genome sequences, promising to aid the interpretation of genomic sequence data. Here, we report an improvement of the prediction accuracy for gene regulatory regions by using the design of convolution layers that efficiently process genomic sequence information, and developed a software, DeepGMAP, to train and compare different deep learning-based models (https://github.com/koonimaru/DeepGMAP). First, we demonstrate that our convolution layers, termed forward- and reverse-sequence scan (FRSS) layers, integrate both forward and reverse strand information, and enhance the power to predict gene regulatory regions. Second, we assessed previous studies and identified problems associated with data structures that caused overfitting. Finally, we introduce visualization methods to examine what the program learned. Together, our FRSS layers improve the prediction accuracy for gene regulatory regions.


Assuntos
DNA/análise , Genoma , Genômica/métodos , Redes Neurais de Computação , Sequências Reguladoras de Ácido Nucleico , Análise de Sequência de DNA/métodos , Software , Animais , DNA/genética , Humanos , Camundongos
11.
Nat Ecol Evol ; 4(2): 261-269, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31907383

RESUMO

Unidirectional fluid flow generated by motile cilia at the left-right organizer (LRO) breaks left-right (L-R) symmetry during early embryogenesis in mouse, frog and zebrafish. The chick embryo, however, does not require motile cilia for L-R symmetry breaking. The diversity of mechanisms for L-R symmetry breaking among vertebrates and the trigger for such symmetry breaking in non-mammalian amniotes have remained unknown. Here we examined how L-R asymmetry is established in two reptiles, Madagascar ground gecko and Chinese softshell turtle. Both of these reptiles appear to lack motile cilia at the LRO. The expression of the Nodal gene at the LRO in the reptilian embryos was found to be asymmetric, in contrast to that in vertebrates such as mouse that are dependent on cilia for L-R patterning. Two paralogues of the Nodal gene derived from an ancient gene duplication are retained and expressed differentially in cilia-dependent and cilia-independent vertebrates. The expression of these two Nodal paralogues is similarly controlled in the lateral plate mesoderm but regulated differently at the LRO. Our in-depth analysis of reptilian embryos thus suggests that mammals and non-mammalian amniotes deploy distinct strategies dependent on different Nodal paralogues for rendering Nodal activity asymmetric at the LRO.


Assuntos
Padronização Corporal , Cílios , Animais , Embrião de Galinha , Madagáscar , Camundongos , Répteis , Peixe-Zebra
12.
Gigascience ; 9(1)2020 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-31919520

RESUMO

BACKGROUND: Hi-C is derived from chromosome conformation capture (3C) and targets chromatin contacts on a genomic scale. This method has also been used frequently in scaffolding nucleotide sequences obtained by de novo genome sequencing and assembly, in which the number of resultant sequences rarely converges to the chromosome number. Despite its prevalent use, the sample preparation methods for Hi-C have not been intensively discussed, especially from the standpoint of genome scaffolding. RESULTS: To gain insight into the best practice of Hi-C scaffolding, we performed a multifaceted methodological comparison using vertebrate samples and optimized various factors during sample preparation, sequencing, and computation. As a result, we identified several key factors that helped improve Hi-C scaffolding, including the choice and preparation of tissues, library preparation conditions, the choice of restriction enzyme(s), and the choice of scaffolding program and its usage. CONCLUSIONS: This study provides the first comparison of multiple sample preparation kits/protocols and computational programs for Hi-C scaffolding by an academic third party. We introduce a customized protocol designated "inexpensive and controllable Hi-C (iconHi-C) protocol," which incorporates the optimal conditions identified in this study, and demonstrate this technique on chromosome-scale genome sequences of the Chinese softshell turtle Pelodiscus sinensis.


Assuntos
Cromatina/genética , Mapeamento Cromossômico , Cromossomos/genética , Biologia Computacional/métodos , Genômica/métodos , Software , Animais , Mapeamento Cromossômico/métodos , Perfilação da Expressão Gênica , Sequenciamento de Nucleotídeos em Larga Escala , Hibridização In Situ , Tartarugas/genética
13.
Proc Biol Sci ; 286(1910): 20191828, 2019 09 11.
Artigo em Inglês | MEDLINE | ID: mdl-31506057

RESUMO

Marine amniotes, a polyphyletic group, provide an excellent opportunity for studying convergent evolution. Their sense of smell tends to degenerate, but this process has not been explored by comparing fully aquatic species with their amphibious relatives in an evolutionary context. Here, we sequenced the genomes of fully aquatic and amphibious sea snakes and identified repertoires of chemosensory receptor genes involved in olfaction. Snakes possess large numbers of the olfactory receptor (OR) genes and the type-2 vomeronasal receptor (V2R) genes, and expression profiling in the olfactory tissues suggests that snakes use the ORs in the main olfactory system (MOS) and the V2Rs in the vomeronasal system (VNS). The number of OR genes has decreased in sea snakes, and fully aquatic species lost MOS which is responsible for detecting airborne odours. By contrast, sea snakes including fully aquatic species retain a number of V2R genes and a well-developed VNS for smelling underwater. This study suggests that the sense of smell also degenerated in sea snakes, particularly in fully aquatic species, but their residual olfactory capability is distinct from that of other fully aquatic amniotes. Amphibious species show an intermediate status between terrestrial and fully aquatic snakes, implying their importance in understanding the process of aquatic adaptation.


Assuntos
Adaptação Fisiológica , Hydrophiidae/fisiologia , Animais , Evolução Biológica , Olfato , Órgão Vomeronasal
14.
Evol Dev ; 21(4): 205-217, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31210006

RESUMO

Nodal is a signaling molecule that belongs to the transforming growth factor-ß superfamily that plays key roles during the early stages of development of animals. In vertebrates Nodal forms an heterodimer with a GDF1/3 protein to activate the Nodal pathway. Vertebrates have a paralog of nodal in their genomes labeled Nodal-related, but the evolutionary history of these genes is a matter of debate, mainly because of the presence of a variable numbers of genes in the vertebrate genomes sequenced so far. Thus, the goal of this study was to investigate the evolutionary history of the Nodal and Nodal-related genes with an emphasis in tracking changes in the number of genes among vertebrates. Our results show the presence of two gene lineages (Nodal and Nodal-related) that can be traced back to the ancestor of jawed vertebrates. These lineages have undergone processes of differential retention and lineage-specific expansions. Our results imply that Nodal and Nodal-related duplicated at the latest in the ancestor of gnathostomes, and they still retain a significant level of functional redundancy. By comparing the evolution of the Nodal/Nodal-related with GDF1/3 gene family, it is possible to infer that there are several types of heterodimers that can trigger the Nodal pathway among vertebrates.


Assuntos
Evolução Molecular , Proteína Nodal/genética , Proteína Nodal/metabolismo , Transdução de Sinais/fisiologia , Vertebrados/genética , Vertebrados/fisiologia , Animais , Biologia Computacional , Regulação da Expressão Gênica , Filogenia
15.
J Exp Biol ; 222(Pt 12)2019 06 27.
Artigo em Inglês | MEDLINE | ID: mdl-31138636

RESUMO

Most cartilaginous fishes live principally in seawater (SW) environments, but a limited number of species including the bull shark, Carcharhinus leucas, inhabit both SW and freshwater (FW) environments during their life cycle. Euryhaline elasmobranchs maintain high internal urea and ion levels even in FW environments, but little is known about the osmoregulatory mechanisms that enable them to maintain internal homeostasis in hypoosmotic environments. In the present study, we focused on the kidney because this is the only organ that can excrete excess water from the body in a hypoosmotic environment. We conducted a transfer experiment of bull sharks from SW to FW and performed differential gene expression analysis between the two conditions using RNA-sequencing. A search for genes upregulated in the FW-acclimated bull shark kidney indicated that the expression of the Na+-Cl- cotransporter (NCC; Slc12a3) was 10 times higher in the FW-acclimated sharks compared with that in SW sharks. In the kidney, apically located NCC was observed in the late distal tubule and in the anterior half of the collecting tubule, where basolateral Na+/K+-ATPase was also expressed, implying that these segments contribute to NaCl reabsorption from the filtrate for diluting the urine. This expression pattern was not observed in the houndshark, Triakis scyllium, which had been transferred to 30% SW; this species cannot survive in FW environments. The salinity transfer experiment combined with a comprehensive gene screening approach demonstrates that NCC is a key renal protein that contributes to the remarkable euryhaline ability of the bull shark.


Assuntos
Aclimatação/genética , Proteínas de Peixes/genética , Salinidade , Tubarões/fisiologia , ATPase Trocadora de Sódio-Potássio/genética , Distribuição Animal , Animais , Proteínas de Peixes/metabolismo , Tubarões/genética , ATPase Trocadora de Sódio-Potássio/metabolismo , Regulação para Cima
16.
Methods Mol Biol ; 1962: 247-256, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31020565

RESUMO

In daily practice of de novo genome assembly and gene prediction, it would be a natural urge to evaluate their products. Different programs and parameter settings give rise to variable outputs, which leaves a decision of which output to adopt for downstream analysis for addressing biological questions. Instead of superficial assessment of length-based statistics of output sequences (e.g., N50 scaffold length), completeness assessment by means of scoring the coverage of reference orthologs has been increasingly utilized.We previously launched a web service, gVolante ( https://gvolante.riken.jp /), to provide a user-friendly interface and a uniform environment for completeness assessment with the pipelines CEGMA and BUSCO. Completeness assessments performed on gVolante report scores based on not just the coverage of reference genes but also on sequence lengths, allowing quality control in multiple aspects. This chapter focuses on the procedure for such assessment and provides technical tips for higher accuracy.


Assuntos
Genoma , Genômica/métodos , Modelos Genéticos , Software , Animais , Elefantes/genética , Roedores/genética , Interface Usuário-Computador
17.
Sci Rep ; 9(1): 3136, 2019 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-30816280

RESUMO

The vertebrate gene repertoire is characterized by "cryptic" genes whose identification has been hampered by their absence from the genomes of well-studied species. One example is the Bmp16 gene, a paralog of the developmental key genes Bmp2 and -4. We focus on the Bmp2/4/16 group of genes to study the evolutionary dynamics following gen(om)e duplications with special emphasis on the poorly studied Bmp16 gene. We reveal the presence of Bmp16 in chondrichthyans in addition to previously reported teleost fishes and reptiles. Using comprehensive, vertebrate-wide gene sampling, our phylogenetic analysis complemented with synteny analyses suggests that Bmp2, -4 and -16 are remnants of a gene quartet that originated during the two rounds of whole-genome duplication (2R-WGD) early in vertebrate evolution. We confirm that Bmp16 genes were lost independently in at least three lineages (mammals, archelosaurs and amphibians) and report that they have elevated rates of sequence evolution. This finding agrees with their more "flexible" deployment during development; while Bmp16 has limited embryonic expression domains in the cloudy catshark, it is broadly expressed in the green anole lizard. Our study illustrates the dynamics of gene family evolution by integrating insights from sequence diversification, gene repertoire changes, and shuffling of expression domains.


Assuntos
Proteína Morfogenética Óssea 2/genética , Proteína Morfogenética Óssea 4/genética , Proteína Morfogenética Óssea 6/genética , Evolução Molecular , Proteínas de Peixes/genética , Peixes/genética , Proteínas de Peixe-Zebra/genética , Animais , Humanos , Filogenia , Peixe-Zebra/genética
18.
Development ; 146(2)2019 01 28.
Artigo em Inglês | MEDLINE | ID: mdl-30630825

RESUMO

Gene regulatory networks underlying cellular pluripotency are controlled by a core circuitry of transcription factors in mammals, including POU5F1. However, the evolutionary origin and transformation of pluripotency-related transcriptional networks have not been elucidated in deuterostomes. PR domain-containing protein 14 (PRDM14) is specifically expressed in pluripotent cells and germ cells, and is required for establishing embryonic stem cells (ESCs) and primordial germ cells in mice. Here, we compared the functions and expression patterns of PRDM14 orthologues within deuterostomes. Amphioxus PRDM14 and zebrafish PRDM14, but not sea urchin PRDM14, compensated for mouse PRDM14 function in maintaining mouse ESC pluripotency. Interestingly, sea urchin PRDM14 together with sea urchin CBFA2T, an essential partner of PRDM14 in mouse ESCs, complemented the self-renewal defect in mouse Prdm14 KO ESCs. Contrary to the Prdm14 expression pattern in mouse embryos, Prdm14 was expressed in motor neurons of amphioxus embryos, as observed in zebrafish embryos. Thus, Prdm14 expression in motor neurons was conserved in non-tetrapod deuterostomes and the co-option of the PRDM14-CBFA2T complex from motor neurons into pluripotent cells may have maintained the transcriptional network for pluripotency during vertebrate evolution.This article has an associated 'The people behind the papers' interview.


Assuntos
Evolução Biológica , Neurônios Motores/metabolismo , Células-Tronco Embrionárias Murinas/metabolismo , Células-Tronco Pluripotentes/metabolismo , Proteínas Repressoras/metabolismo , Fatores de Transcrição/metabolismo , Vertebrados/metabolismo , Sequência de Aminoácidos , Animais , Biomarcadores/metabolismo , Desmetilação do DNA , Metilação de DNA , Proteínas de Ligação a DNA , Embrião não Mamífero/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Anfioxos/embriologia , Anfioxos/metabolismo , Camundongos , Camundongos Knockout , Filogenia , Ligação Proteica , Domínios Proteicos , Proteínas de Ligação a RNA , Proteínas Repressoras/química , Ouriços-do-Mar/embriologia , Ouriços-do-Mar/metabolismo , Homologia de Sequência do Ácido Nucleico , Sintenia/genética , Vertebrados/embriologia , Peixe-Zebra/embriologia , Peixe-Zebra/metabolismo
19.
Dev Growth Differ ; 61(1): 97-103, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30644548

RESUMO

In amniotes, limb muscle precursors de-epithelialize from the ventral dermomyotome and individually migrate into limb buds. In catsharks, Scyliorhinus, fin muscle precursors are also derived from the ventral dermomyotome, but shortly after de-epithelialization, they reaggregate within the pectoral fin bud and differentiate into fin muscles. Delamination of muscle precursors has been suggested to be controlled by hepatocyte growth factor (HGF) and its tyrosine kinase receptor (MET) in amniotes. Here, we explore the possibility that HGF/MET signaling regulates the delamination of appendicular muscle precursors in embryos of the catshark Scyliorhinus canicula. Our analysis reveals that Hgf is expressed in pectoral fin buds, whereas c-Met expression in fin muscle precursors is rapidly downregulated. We propose that alteration of the duration of c-Met expression in appendicular muscle precursors might underlie the evolution of individually migrating muscle precursors, which leads to the emergence of complex appendicular muscular systems in amniotes.


Assuntos
Fator de Crescimento de Hepatócito/metabolismo , Músculo Esquelético/embriologia , Músculo Esquelético/metabolismo , Receptores Proteína Tirosina Quinases/metabolismo , Tubarões/embriologia , Tubarões/metabolismo , Transdução de Sinais , Animais , Desenvolvimento Muscular , Músculo Esquelético/citologia , Músculo Esquelético/enzimologia
20.
Sci Data ; 5: 180197, 2018 10 08.
Artigo em Inglês | MEDLINE | ID: mdl-30295671

RESUMO

Although cartilaginous fishes have played crucial roles in various fields, including evolutionary biology, marine ecology, bioresources, and aquarium exhibitions, molecular information for these species is poorly available. The present study reports a transcriptome assembly from an embryo of the zebra bullhead shark (Heterodontus zebra), produced by paired-end RNA sequencing. Transcriptome data is generated with a de novo transcriptome assembler, Trinity. Amino acid sequences are predicted from the assemblies, using TransDecoder. Because cartilaginous fishes serve as the outgroup of bony vertebrates, the data would contribute to comparative analyses of a various biological fields. In addition, this study would be useful for conservation biology, such as transcriptome-based population genetics.


Assuntos
Tubarões/genética , Transcriptoma , Animais , Perfilação da Expressão Gênica , Análise de Sequência de RNA
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