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1.
Cells ; 11(23)2022 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-36496987

RESUMO

Understanding how neurons regenerate following injury remains a central challenge in regenerative medicine. Adult mammals have a very limited ability to regenerate new neurons in the central nervous system (CNS). In contrast, the basal chordate Polycarpa mytiligera can regenerate its entire CNS within seven days of complete removal. Transcriptome sequencing, cellular labeling, and proliferation in vivo essays revealed that CNS regeneration is mediated by a newly formed neural progeny and the activation of neurodevelopmental pathways that are associated with enhanced stem-cell activity. Analyzing the expression of 239 activated pathways enabled a quantitative understanding of gene-set enrichment patterns at key regeneration stages. The molecular and cellular mechanisms controlling the regenerative ability that this study reveals can be used to develop innovative approaches to enhancing neurogenesis in closely-related chordate species, including humans.


Assuntos
Regeneração do Cérebro , Cordados , Animais , Humanos , Neurogênese/fisiologia , Sistema Nervoso Central/metabolismo , Encéfalo , Mamíferos
2.
Int J Mol Sci ; 23(22)2022 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-36430885

RESUMO

Osmoregulation is essential for organisms to adapt to the exterior environment and plays an important role in embryonic organogenesis. Tubular organ formation usually involves a hyperosmotic lumen environment. The mechanisms of how the cells respond and regulate lumen formation remain largely unknown. Here, we reported that the nuclear factor of activated T cells-5 (NFAT5), the only transcription factor in the NFAT family involved in the cellular responses to hypertonic stress, regulated notochord lumen formation in chordate Ciona. Ciona NFAT5 (Ci-NFAT5) was expressed in notochord, and its expression level increased during notochord lumen formation and expansion. Knockout and expression of the dominant negative of NFAT5 in Ciona embryos resulted in the failure of notochord lumen expansion. We further demonstrated that the Ci-NFAT5 transferred from the cytoplasm into nuclei in HeLa cells under the hyperosmotic medium, indicating Ci-NFAT5 can respond the hypertonicity. To reveal the underly mechanisms, we predicted potential downstream genes of Ci-NFAT5 and further validated Ci-NFAT5-interacted genes by the luciferase assay. The results showed that Ci-NFAT5 promoted SLC26A6 expression. Furthermore, expression of a transport inactivity mutant of SLC26A6 (L421P) in notochord led to the failure of lumen expansion, phenocopying that of Ci-NFAT5 knockout. These results suggest that Ci-NFAT5 regulates notochord lumen expansion via the SLC26A6 axis. Taken together, our results reveal that the chordate NFAT5 responds to hypertonic stress and regulates lumen osmotic pressure via an ion channel pathway on luminal organ formation.


Assuntos
Cordados , Ciona , Animais , Humanos , Notocorda/metabolismo , Células HeLa , Linfócitos T , Núcleo Celular
3.
J Mol Evol ; 90(6): 418-428, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36181519

RESUMO

Vertebrate blood coagulation is controlled by a cascade containing more than 20 proteins. The cascade proteins are found in the blood in their zymogen forms and when the cascade is triggered by tissue damage, zymogens are activated and in turn activate their downstream proteins by serine protease activity. In this study, we examined proteomes of 21 chordates, of which 18 are vertebrates, to reveal the modular evolution of the blood coagulation cascade. Additionally, two Arthropoda species were used to compare domain arrangements of the proteins belonging to the hemolymph clotting and the blood coagulation cascades. Within the vertebrate coagulation protein set, almost half of the studied proteins are shared with jawless vertebrates. Domain similarity analyses revealed that there are multiple possible evolutionary trajectories for each coagulation protein. During the evolution of higher vertebrate clades, gene and genome duplications led to the formation of other coagulation cascade proteins.


Assuntos
Fatores de Coagulação Sanguínea , Cordados , Animais , Fatores de Coagulação Sanguínea/genética , Fatores de Coagulação Sanguínea/metabolismo , Vertebrados/genética , Coagulação Sanguínea/genética , Cordados/genética , Genoma
4.
Gen Comp Endocrinol ; 328: 114123, 2022 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-36075341

RESUMO

The calcitonin (CT)/CT gene-related peptide (CGRP) family is a peptide gene family that is widely found in bilaterians. CT, CGRP, adrenomedullin (AM), amylin (AMY), and CT receptor-stimulating peptide (CRSP) are members of the CT/CGRP family. In mammals, CT is involved in calcium homeostasis, while CGRP and AM primarily function in vasodilation. AMY and CRSP are associated with anorectic effects. Diversification of the molecular features and physiological functions of the CT/CGRP family in vertebrate lineages have been extensively reported. However, the origin and diversification mechanisms of the vertebrate CT/CGRP family of peptides remain unclear. In this review, the molecular characteristics of CT/CGRP family peptides and their receptors, along with their major physiological functions in mammals and teleosts, are introduced. Furthermore, novel candidates of the CT/CGRP family in cartilaginous fish are presented based on genomic information. The CT/CGRP family peptides and receptors in urochordates and cephalochordates, which are closely related to vertebrates, are also described. Finally, a putative evolutionary scenario of the CT/CGRP family peptides and receptors in chordates is discussed.


Assuntos
Depressores do Apetite , Cordados , Neuropeptídeos , Hormônios Peptídicos , Adrenomedulina , Animais , Calcitonina/genética , Peptídeo Relacionado com Gene de Calcitonina/química , Peptídeo Relacionado com Gene de Calcitonina/genética , Cálcio , Peixes/genética , Polipeptídeo Amiloide das Ilhotas Pancreáticas , Mamíferos , Proteínas Modificadoras da Atividade de Receptores , Receptores da Calcitonina/genética , Tomografia Computadorizada por Raios X , Vertebrados
5.
Nature ; 609(7927): 541-546, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35978194

RESUMO

The early history of deuterostomes, the group composed of the chordates, echinoderms and hemichordates1, is still controversial, not least because of a paucity of stem representatives of these clades2-5. The early Cambrian microscopic animal Saccorhytus coronarius was interpreted as an early deuterostome on the basis of purported pharyngeal openings, providing evidence for a meiofaunal ancestry6 and an explanation for the temporal mismatch between palaeontological and molecular clock timescales of animal evolution6-8. Here we report new material of S. coronarius, which is reconstructed as a millimetric and ellipsoidal meiobenthic animal with spinose armour and a terminal mouth but no anus. Purported pharyngeal openings in support of the deuterostome hypothesis6 are shown to be taphonomic artefacts. Phylogenetic analyses indicate that S. coronarius belongs to total-group Ecdysozoa, expanding the morphological disparity and ecological diversity of early Cambrian ecdysozoans.


Assuntos
Cordados , Filogenia , Animais , Cordados/anatomia & histologia , Fósseis , Boca , Paleontologia
6.
Sci China Life Sci ; 65(12): 2539-2551, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-35696018

RESUMO

Olfactory receptors are poorly annotated for most genome-sequenced chordates. To address this deficiency, we developed a nhmmer-based olfactory receptor annotation tool Genome2OR ( https://github.com/ToHanwei/Genome2OR.git ), and used it to process 1,695 sequenced chordate genomes in the NCBI Assembly database as of January, 2021. In total, 765,248 olfactory receptor genes were annotated, with 404,426 functional genes and 360,822 pseudogenes, which represents a four-fold increase in the number of annotated olfactory receptors. Based on the annotation data, we built a database called Chordata Olfactory Receptor Database (CORD, https://cord.ihuman.shanghaitech.edu.cn ) for archiving, analysing and disseminating the data. Beyond the primary data, we offer derivative information, including pictures of species, cross references to public databases, structural models, sequence similarity networks and sequence profiles in the CORD. Furthermore, we did brief analyses on these receptors, including building a huge protein sequence similarity network covering all receptors in the database, and clustering them into 20 communities, classifying the 20 communities into three categories based on their presences/absences in ray-finned fish and/or lobe-finned fish. We infer that olfactory receptors should have unique activation and desensitization mechanisms by analysing their sequences and structural models. We believe the CORD can benefit the researchers and the general public who are interested in olfaction.


Assuntos
Cordados , Receptores Odorantes , Animais , Receptores Odorantes/genética , Cordados/genética , Pseudogenes , Sequência de Aminoácidos , Genoma/genética
7.
Proc Biol Sci ; 289(1974): 20220258, 2022 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-35538784

RESUMO

Deuterostomes comprise three phyla with radically different body plans. Phylogenetic bracketing of the living deuterostome clades suggests the latest common ancestor of echinoderms, hemichordates and chordates was a bilaterally symmetrical worm with pharyngeal openings, with these characters lost in echinoderms. Early fossil echinoderms with pharyngeal openings have been described, but their interpretation is highly controversial. Here, we critically evaluate the evidence for pharyngeal structures (gill bars) in the extinct stylophoran echinoderms Lagynocystis pyramidalis and Jaekelocarpus oklahomensis using virtual models based on high-resolution X-ray tomography scans of three-dimensionally preserved fossil specimens. Multivariate analyses of the size, spacing and arrangement of the internal bars in these fossils indicate they are substantially more similar to gill bars in modern enteropneust hemichordates and cephalochordates than to other internal bar-like structures in fossil blastozoan echinoderms. The close similarity between the internal bars of the stylophorans L. pyramidalis and J. oklahomensis and the gill bars of extant chordates and hemichordates is strong evidence for their homology. Differences between these internal bars and bar-like elements of the respiratory systems in blastozoans suggest these structures might have arisen through parallel evolution across deuterostomes, perhaps underpinned by a common developmental genetic mechanism.


Assuntos
Cordados não Vertebrados , Cordados , Animais , Evolução Biológica , Cordados não Vertebrados/genética , Equinodermos , Fósseis , Brânquias , Filogenia
8.
Methods Mol Biol ; 2450: 293-309, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35359314

RESUMO

Hemichordates are benthic marine invertebrates closely related to chordates. Several species, including Ptychodera flava in the phylum Hemichordates, can undergo whole body regeneration from a small fragment. P. flava is widely distributed in the warm Indo-Pacific region and is easily collected in the lower tidal zone of a shallow beach with a coral reef. Here, we describe the methods for animal collection and preparation of regenerating tissues. The prepared tissues can be used for various molecular and/or histological experiments. We also demonstrate how to examine gene expression patterns in the tissues using whole mount in situ hybridization.


Assuntos
Cordados , Animais , Organismos Aquáticos , Pesquisa
9.
Cells ; 11(8)2022 04 12.
Artigo em Inglês | MEDLINE | ID: mdl-35455988

RESUMO

The anterior-posterior (AP) axis in chordates is regulated by a conserved set of genes and signaling pathways, including Hox genes and retinoic acid (RA), which play well-characterized roles in the organization of the chordate body plan. The intermediate mesoderm (IM), which gives rise to all vertebrate kidneys, is an example of a tissue that differentiates sequentially along this axis. Yet, the conservation of the spatiotemporal regulation of the IM across vertebrates remains poorly understood. In this study, we used a comparative developmental approach focusing on non-conventional model organisms, a chondrichthyan (catshark), a cyclostome (lamprey), and a cephalochordate (amphioxus), to assess the involvement of RA in the regulation of chordate and vertebrate pronephros formation. We report that the anterior expression boundary of early pronephric markers (Pax2 and Lim1), positioned at the level of somite 6 in amniotes, is conserved in the catshark and the lamprey. Furthermore, RA, driving the expression of Hox4 genes like in amniotes, regulates the anterior pronephros boundary in the catshark. We find no evidence for the involvement of this regulatory hierarchy in the AP positioning of the lamprey pronephros and the amphioxus pronephros homolog, Hatschek's nephridium. This suggests that despite the conservation of Pax2 and Lim1 expressions in chordate pronephros homologs, the responsiveness of the IM, and hence of pronephric genes, to RA- and Hox-dependent regulation is a gnathostome novelty.


Assuntos
Cordados , Pronefro , Animais , Genes Homeobox , Lampreias , Tretinoína/farmacologia , Vertebrados/genética
10.
Zootaxa ; 5093(3): 296-314, 2022 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-35391485

RESUMO

Deep-sea benthic communities from the Weddell Sea, Antarctica, were sampled in JanuaryApril 2005 in an area located between 61S70S and 0W49W. We found a total of eight ascidian species that belong to five different families, of which one corresponded to a new species. These were: Protoholozoa pedunculata Kott, 1969; Corynascidia suhmi Herdman, 1882; Styela andeepensis Maggioni Tatin sp. nov.; Culeolus suhmi Herman, 1881; Culeolus anonymus Monniot F. Monniot C., 1976; Culeolus likae Sanamyan K. Sanamyan N., 2002; Oligotrema lyra (Monniot C. Monniot F., 1973) and Asajirus indicus (Oka, 1913). We report: the extension of the known distribution ranges of P. pedunculata, Corynascidia suhmi, Culeolus suhmi, C. likae and A. indicus, being the first time they are collected from the Weddell Sea; and the shallowest record of C. likae. Six species were added to the list of ascidians of the Weddell Sea, being all deep-sea representatives. While the total number of ascidian species augmented from 43 to 49, the number of deep-sea representatives increased from 23 to 29. Our findings, thus, reinforce the need of performing more deep-sea prospections in the area.


Assuntos
Cordados , Thoracica , Urocordados , Animais , Regiões Antárticas , Conteúdo Gastrointestinal , Humanos
11.
Curr Top Dev Biol ; 147: 545-562, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35337462

RESUMO

Hemichordates have long been recognized as a critical group for addressing hypotheses of chordate origins. Historically this was due to anatomical traits that resembled those of chordates, most strikingly the dorsolateral gill slits. As molecular data and phylogenetic analyses were found to support a close phylogenetic relationship between hemichordates and chordates within the deuterostomes, interest was revived in hemichordates. In particular, Saccoglossus kowalevskii has been developed as a molecular model to represent hemichordate developmental biology. Herein, we highlight the considerations when choosing a particular species to study and the challenges we encountered when developing S. kowalevskii. We discuss our findings and how method and tool development enabled them, and how we envision expanding our repertoire of molecular tools in the future. Establishing a new model organism comes with many obstacles-from identifying a reliable season to collect animals, to developing modern molecular techniques. The Saccoglossus research community has benefited greatly from the collaborations and teamwork established over the years. As a result, Saccoglossus is well positioned to contribute to a new century of evolutionary developmental (evo-devo) research.


Assuntos
Cordados , Animais , Evolução Biológica , Filogenia
12.
Cells ; 11(3)2022 02 02.
Artigo em Inglês | MEDLINE | ID: mdl-35159332

RESUMO

Although a recent genomic survey revealed its ancient evolutionary origin in the animal kingdom, retinoic acid (RA) signaling was previously thought to be unique to chordates. Echinoderms are of critical interest in researching the evolutionary history of RA signaling, as they represent a basal group of deuterostomes. Furthermore, our previous works have suggested that echinoderms may possess the ancestral function of RA signaling for metamorphosis regulation. In this paper, to facilitate future studies of RA signaling in echinoderms, we provide an overview of RA machinery in echinoderms, identify its signaling components, and discuss its developmental role.


Assuntos
Cordados , Tretinoína , Animais , Evolução Biológica , Equinodermos , Transdução de Sinais/fisiologia
13.
Dev Growth Differ ; 64(3): 120-137, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35048372

RESUMO

Wnt signaling is essential during animal development and regeneration, but also plays an important role in diseases such as cancer and diabetes. The canonical Wnt signaling pathway is one of the most conserved signaling cascades in the animal kingdom, with the T-cell factor/lymphoid enhancer factor (TCF/LEF) proteins being the major mediators of Wnt/ß-catenin-regulated gene expression. In comparison with invertebrates, vertebrates possess a high diversity of TCF/LEF family genes, implicating this as a possible key change to Wnt signaling at the evolutionary origin of vertebrates. However, the precise nature of this diversification is only poorly understood. The aim of this study is to clarify orthology, paralogy, and isoform relationships within the TCF/LEF gene family within chordates via in silico comparative study of TCF/LEF gene structure, molecular phylogeny, and gene synteny. Our results support the notion that the four TCF/LEF paralog subfamilies in jawed vertebrates (gnathostomes) evolved via the two rounds of whole-genome duplications that occurred during early vertebrate evolution. Importantly, gene structure comparisons and synteny analysis of jawless vertebrate (cyclostome) TCFs suggest that a TCF7L2-like form of gene structure is a close proxy for the ancestral vertebrate structure. In conclusion, we propose a detailed evolutionary path based on a new pre-whole-genome duplication vertebrate TCF gene model. This ancestor gene model highlights the chordate and vertebrate innovations of TCF/LEF gene structure, providing the foundation for understanding the role of Wnt/ß-catenin signaling in vertebrate evolution.


Assuntos
Cordados , Via de Sinalização Wnt , Animais , Cordados/metabolismo , Fator 1 de Ligação ao Facilitador Linfoide/genética , Vertebrados/genética , Vertebrados/metabolismo , Via de Sinalização Wnt/genética , beta Catenina/genética
14.
Elife ; 112022 01 19.
Artigo em Inglês | MEDLINE | ID: mdl-35042580

RESUMO

Gap junction channels are formed by two unrelated protein families. Non-chordates use the primordial innexins, while chordates use connexins that superseded the gap junction function of innexins. Chordates retained innexin-homologs, but N-glycosylation prevents them from forming gap junctions. It is puzzling why chordates seem to exclusively use the new gap junction protein and why no chordates should exist that use non-glycosylated innexins to form gap junctions. Here, we identified glycosylation sites of 2388 innexins from 174 non-chordate and 276 chordate species. Among all chordates, we found not a single innexin without glycosylation sites. Surprisingly, the glycosylation motif is also widespread among non-chordate innexins indicating that glycosylated innexins are not a novelty of chordates. In addition, we discovered a loss of innexin diversity during early chordate evolution. Most importantly, lancelets, which lack connexins, exclusively possess only one highly conserved innexin with one glycosylation site. A bottleneck effect might thus explain why connexins have become the only protein used to form chordate gap junctions.


Assuntos
Cordados/genética , Conexinas/genética , Evolução Molecular , Junções Comunicantes/genética , Animais , Junções Comunicantes/metabolismo
15.
Methods Mol Biol ; 2303: 93-109, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34626373

RESUMO

Sulfate polysaccharides with unique structures of the chondroitin/dermatan and heparin/heparan families of sulfated glycosaminoglycans have been described in several species of ascidians (Chordata-Tunicata). These unique sulfated glycans have been isolated from the ascidians and characterized by biochemical and spectroscopic methods. The ascidian glycans can be extracted by different tissues or cells by proteolytic digestion followed by cetylpyridinium chloride/ethanol precipitation. The total glycans are then fractionated by ion-exchange chromatography on DEAE-cellulose and/or Mono Q (HR 5/5) columns. Alternatively, precipitation with different ethanol concentrations can be employed. An initial analysis of the purified ascidian glycans is carried out by agarose gel electrophoresis on diaminopropane/acetate buffer, before or after digestion with specific glycosaminoglycan lyases or deaminative cleavage with nitrous acid. The disaccharides formed by exhaustive degradation of the glycans are purified by gel-filtration chromatography on a Superdex Peptide column and analyzed by HPLC on a strong ion-exchange Sax Spherisorb column. 1H- or 13C-nuclear magnetic resonance spectroscopy in one or two dimensions is used to confirm the structure of the intact glycans.


Assuntos
Cordados , Urocordados , Animais , Sulfatos de Condroitina , Dermatan Sulfato , Etanol , Glicosaminoglicanos , Polissacarídeos , Sulfatos
16.
Philos Trans R Soc Lond B Biol Sci ; 377(1844): 20200522, 2022 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-34957850

RESUMO

This article outlines a hypothetical sequence of evolutionary innovations, along the lineage that produced humans, which extended behavioural control from simple feedback loops to sophisticated control of diverse species-typical actions. I begin with basic feedback mechanisms of ancient mobile animals and follow the major niche transitions from aquatic to terrestrial life, the retreat into nocturnality in early mammals, the transition to arboreal life and the return to diurnality. Along the way, I propose a sequence of elaboration and diversification of the behavioural repertoire and associated neuroanatomical substrates. This includes midbrain control of approach versus escape actions, telencephalic control of local versus long-range foraging, detection of affordances by the dorsal pallium, diversified control of nocturnal foraging in the mammalian neocortex and expansion of primate frontal, temporal and parietal cortex to support a wide variety of primate-specific behavioural strategies. The result is a proposed functional architecture consisting of parallel control systems, each dedicated to specifying the affordances for guiding particular species-typical actions, which compete against each other through a hierarchy of selection mechanisms. This article is part of the theme issue 'Systems neuroscience through the lens of evolutionary theory'.


Assuntos
Cordados , Neocórtex , Animais , Controle Comportamental , Evolução Biológica , Mamíferos , Primatas
17.
Dev Growth Differ ; 64(1): 67-82, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34964127

RESUMO

The larvacean Oikopleura dioica is a cosmopolitan planktonic chordate and is closely related to vertebrates. It is characterized by a tadpole-shaped morphology with notochord flanked by muscle in the tail and brain on the dorsal side, a short life cycle of five days, a compact genome of approximately 56 Mb, a simple and transparent body with a small number of cells (~4000 in functional juveniles), invariant embryonic cell lineages, and fast development that ensures complete morphogenesis and organ formation 10 h after fertilization. With these features, this marine chordate is a promising and advantageous animal model in which genetic manipulation is feasible. In this review, we introduce relevant resources and modern techniques that have been developed: (1) Genome and transcriptomes. Oikopleura dioica has the smallest genome among non-parasitic metazoans. Its genome databases have been generated using three geographically distant O. dioica populations, and several intra-species sequence differences are becoming evident; (2) Functional genetic knockdown techniques. Comprehensive screening of genes is feasible using ovarian microinjection and double-strand DNA-induced gene knockdown; and (3) Live imaging of embryos and larvae. Application of these techniques has uncovered novel aspects of development, including meiotic cell arrest, left-right patterning, epidermal cell patterning, and mouth formation involving the connection of ectoderm and endoderm sheets. Oikopleura dioca has become very useful for developmental and evolutionary studies in chordates.


Assuntos
Cordados , Urocordados , Animais , Biologia do Desenvolvimento , Genoma , Morfogênese , Urocordados/genética
18.
Cells ; 10(12)2021 12 02.
Artigo em Inglês | MEDLINE | ID: mdl-34943899

RESUMO

The specification of the endostyle in non-vertebrate chordates and of the thyroid gland in vertebrates are fundamental steps in the evolution of the thyroid hormone (TH) signaling to coordinate development and body physiology in response to a range of environmental signals. The physiology and biology of TH signaling in vertebrates have been studied in the past, but a complete understanding of such a complex system is still lacking. Non-model species from non-vertebrate chordates may greatly improve our understanding of the evolution of this complex endocrine pathway. Adaptation of already existing proteins in order to perform new roles is a common feature observed during the course of evolution. Through sequence similarity approaches, we investigated the presence of bona fide thyroid peroxidase (TPO), iodothyronine deiodinase (DIO), and thyroid hormone receptors (THRs) in non-vertebrate and vertebrate chordates. Additionally, we determined both the conservation and divergence degrees of functional domains at the protein level. This study supports the hypothesis that non-vertebrate chordates have a functional thyroid hormone signaling system and provides additional information about its possible evolutionary adaptation.


Assuntos
Evolução Biológica , Iodeto Peroxidase/genética , Receptores dos Hormônios Tireóideos/genética , Hormônios Tireóideos/genética , Sequência de Aminoácidos/genética , Animais , Cefalocordados/genética , Cordados/genética , Regulação da Expressão Gênica no Desenvolvimento/genética , Alinhamento de Sequência , Transdução de Sinais/genética , Glândula Tireoide/metabolismo , Urocordados/genética , Vertebrados/genética
19.
Cells ; 10(12)2021 12 02.
Artigo em Inglês | MEDLINE | ID: mdl-34943900

RESUMO

Glycine is an important neurotransmitter in vertebrates, performing both excitatory and inhibitory actions. Synaptic levels of glycine are tightly controlled by the action of two glycine transporters, GlyT1 and GlyT2, located on the surface of glial cells and neurons, respectively. Only limited information is available on glycinergic neurotransmission in invertebrates, and the evolution of glycinergic neurotransmission is poorly understood. Here, by combining phylogenetic and gene expression analyses, we characterized the glycine transporter complement of amphioxus, an important invertebrate model for studying the evolution of chordates. We show that amphioxus possess three glycine transporter genes. Two of these (GlyT2.1 and GlyT2.2) are closely related to GlyT2 of vertebrates, whereas the third (GlyT) is a member of an ancestral clade of deuterostome glycine transporters. GlyT2.2 expression is predominantly non-neural, whereas GlyT and GlyT2.1 are widely expressed in the amphioxus nervous system and are differentially expressed, respectively, in neurons and glia. Vertebrate glycinergic neurons express GlyT2 and glia GlyT1, suggesting that the evolution of the chordate glycinergic system was accompanied by a paralog-specific inversion of gene expression. Despite this genetic divergence between amphioxus and vertebrates, we found strong evidence for conservation in the role glycinergic neurotransmission plays during larval swimming, the implication being that the neural networks controlling the rhythmic movement of chordate bodies may be homologous.


Assuntos
Evolução Molecular , Proteínas da Membrana Plasmática de Transporte de Glicina/genética , Glicina/genética , Transmissão Sináptica/genética , Animais , Cordados/genética , Cordados/crescimento & desenvolvimento , Regulação da Expressão Gênica/genética , Variação Genética/genética , Glicina/metabolismo , Anfioxos/genética , Larva/genética , Larva/crescimento & desenvolvimento , Neuroglia/metabolismo , Neurônios/metabolismo , Filogenia
20.
Proc Natl Acad Sci U S A ; 118(52)2021 12 28.
Artigo em Inglês | MEDLINE | ID: mdl-34862323

RESUMO

In less than 25 y, the field of animal genome science has transformed from a discipline seeking its first glimpses into genome sequences across the Tree of Life to a global enterprise with ambitions to sequence genomes for all of Earth's eukaryotic diversity [H. A. Lewin et al., Proc. Natl. Acad. Sci. U.S.A. 115, 4325-4333 (2018)]. As the field rapidly moves forward, it is important to take stock of the progress that has been made to best inform the discipline's future. In this Perspective, we provide a contemporary, quantitative overview of animal genome sequencing. We identified the best available genome assemblies in GenBank, the world's most extensive genetic database, for 3,278 unique animal species across 24 phyla. We assessed taxonomic representation, assembly quality, and annotation status for major clades. We show that while tremendous taxonomic progress has occurred, stark disparities in genomic representation exist, highlighted by a systemic overrepresentation of vertebrates and underrepresentation of arthropods. In terms of assembly quality, long-read sequencing has dramatically improved contiguity, whereas gene annotations are available for just 34.3% of taxa. Furthermore, we show that animal genome science has diversified in recent years with an ever-expanding pool of researchers participating. However, the field still appears to be dominated by institutions in the Global North, which have been listed as the submitting institution for 77% of all assemblies. We conclude by offering recommendations for improving genomic resource availability and research value while also broadening global representation.


Assuntos
Artrópodes/genética , Bases de Dados Genéticas , Genoma/genética , Genômica , Vertebrados/genética , Animais , Cordados/genética , Sequenciamento de Nucleotídeos em Larga Escala , Invertebrados/genética , Análise de Sequência de DNA
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