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1.
Nature ; 613(7943): 324-331, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36599989

RESUMO

Pathogens generate ubiquitous selective pressures and host-pathogen interactions alter social behaviours in many animals1-4. However, very little is known about the neuronal mechanisms underlying pathogen-induced changes in social behaviour. Here we show that in adult Caenorhabditis elegans hermaphrodites, exposure to a bacterial pathogen (Pseudomonas aeruginosa) modulates sensory responses to pheromones by inducing the expression of the chemoreceptor STR-44 to promote mating. Under standard conditions, C. elegans hermaphrodites avoid a mixture of ascaroside pheromones to facilitate dispersal5-13. We find that exposure to the pathogenic Pseudomonas bacteria enables pheromone responses in AWA sensory neurons, which mediate attractive chemotaxis, to suppress the avoidance. Pathogen exposure induces str-44 expression in AWA neurons, a process regulated by a transcription factor zip-5 that also displays a pathogen-induced increase in expression in AWA. STR-44 acts as a pheromone receptor and its function in AWA neurons is required for pathogen-induced AWA pheromone response and suppression of pheromone avoidance. Furthermore, we show that C. elegans hermaphrodites, which reproduce mainly through self-fertilization, increase the rate of mating with males after pathogen exposure and that this increase requires str-44 in AWA neurons. Thus, our results uncover a causal mechanism for pathogen-induced social behaviour plasticity, which can promote genetic diversity and facilitate adaptation of the host animals.


Assuntos
Caenorhabditis elegans , Feromônios , Pseudomonas aeruginosa , Reprodução , Comportamento Sexual Animal , Animais , Feminino , Masculino , Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/microbiologia , Caenorhabditis elegans/fisiologia , Proteínas de Caenorhabditis elegans/metabolismo , Glicolipídeos/metabolismo , Organismos Hermafroditas/fisiologia , Feromônios/metabolismo , Pseudomonas aeruginosa/patogenicidade , Pseudomonas aeruginosa/fisiologia , Receptores de Feromônios/metabolismo , Reprodução/fisiologia , Células Receptoras Sensoriais/metabolismo
2.
Curr Biol ; 32(10): R477-R479, 2022 05 23.
Artigo em Inglês | MEDLINE | ID: mdl-35609548

RESUMO

Mitochondria - the cell's power stations - are inherited uniparentally via eggs, not sperm. In hermaphroditic plants, they sometimes prevent their hosts from making pollen (and sperm), causing cytoplasmic male sterility. New evidence from a hermaphroditic freshwater snail now documents cytoplasmic male sterility in animals.


Assuntos
Organismos Hermafroditas , Mitocôndrias , Caramujos , Animais , Citoplasma
3.
Artigo em Inglês | MEDLINE | ID: mdl-34737084

RESUMO

We tested whether crowding stress affects the hypothalamo-pituitary-interrenal (HPI) axis of the self-fertilizing fish, Kryptolebias marmoratus, which is known to be aggressive in the laboratory conditions but sometimes found as a group from a single land crab burrow in the wild. The projection of corticotropin-releasing hormone (CRH) neurons to the adrenocorticotropic hormone (ACTH) cells in the pituitary was confirmed by dual-label immunohistochemistry; CRH-immunoreactive (ir) fibers originating from cell bodies located in the lateral tuberal nucleus (NLT) of the hypothalamus were observed to project to ACTH-ir cells in the rostral pars distalis of the pituitary. Then, fish were reared solitary or in pairs for 14 days, and the number of CRH-ir cell bodies in the NLT of the hypothalamus and cortisol levels in the body without head region were compared. The number of CRH-ir cell bodies and cortisol levels were significantly higher in paired fish. These results indicate that crowding stress affects the HPI axis in K. marmoratus which thrive in small burrows with limited water volume.


Assuntos
Ciprinodontiformes/fisiologia , Sistema Hipotálamo-Hipofisário/fisiologia , Peixes Listrados/fisiologia , Autofertilização/fisiologia , Hormônio Adrenocorticotrópico/fisiologia , Animais , Hormônio Liberador da Corticotropina/fisiologia , Ciprinodontiformes/anatomia & histologia , Feminino , Proteínas de Peixes/fisiologia , Organismos Hermafroditas/fisiologia , Sistema Hipotálamo-Hipofisário/anatomia & histologia , Imuno-Histoquímica , Rim/fisiologia , Peixes Listrados/anatomia & histologia , Masculino , Fibras Nervosas/fisiologia , Estresse Fisiológico
4.
Sci Rep ; 11(1): 22881, 2021 11 24.
Artigo em Inglês | MEDLINE | ID: mdl-34819550

RESUMO

The stunning sexual transformation commonly triggered by age, size or social context in some fishes is one of the best examples of phenotypic plasticity thus far described. To date our understanding of this process is dominated by studies on a handful of subtropical and tropical teleosts, often in wild settings. Here we have established the protogynous New Zealand spotty wrasse, Notolabrus celidotus, as a temperate model for the experimental investigation of sex change. Captive fish were induced to change sex using aromatase inhibition or manipulation of social groups. Complete female-to-male transition occurred over 60 days in both cases and time-series sampling was used to quantify changes in hormone production, gene expression and gonadal cellular anatomy. Early-stage decreases in plasma 17ß-estradiol (E2) concentrations or gonadal aromatase (cyp19a1a) expression were not detected in spotty wrasse, despite these being commonly associated with the onset of sex change in subtropical and tropical protogynous (female-to-male) hermaphrodites. In contrast, expression of the masculinising factor amh (anti-Müllerian hormone) increased during early sex change, implying a potential role as a proximate trigger for masculinisation. Collectively, these data provide a foundation for the spotty wrasse as a temperate teleost model to study sex change and cell fate in vertebrates.


Assuntos
Peixes/fisiologia , Organismos Hermafroditas/fisiologia , Processos de Determinação Sexual , Animais , Hormônio Antimülleriano/genética , Hormônio Antimülleriano/metabolismo , Inibidores da Aromatase/farmacologia , Estradiol/sangue , Feminino , Proteínas de Peixes/genética , Proteínas de Peixes/metabolismo , Peixes/sangue , Peixes/genética , Regulação da Expressão Gênica , Gônadas/fisiologia , Organismos Hermafroditas/efeitos dos fármacos , Organismos Hermafroditas/genética , Organismos Hermafroditas/metabolismo , Masculino , Modelos Animais , Fenótipo , Caracteres Sexuais , Processos de Determinação Sexual/efeitos dos fármacos , Comportamento Social , Testosterona/análogos & derivados , Testosterona/sangue
5.
Int J Mol Sci ; 22(22)2021 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-34830486

RESUMO

Spermatogenesis is a process of self-renewal and differentiation in spermatogonial stem cells. During this process, germ cells and somatic cells interact intricately to ensure long-term fertility and accurate genome propagation. Spermatogenesis has been intensely investigated in mammals but remains poorly understood with regard to teleosts. Here, we performed single-cell RNA sequencing of ~9500 testicular cells from the male, orange-spotted grouper. In the adult testis, we divided the cells into nine clusters and defined ten cell types, as compared with human testis data, including cell populations with characteristics of male germ cells and somatic cells, each of which expressed specific marker genes. We also identified and profiled the expression patterns of four marker genes (calr, eef1a, s100a1, vasa) in both the ovary and adult testis. Our data provide a blueprint of male germ cells and supporting somatic cells. Moreover, the cell markers are candidates that could be used for further cell identification.


Assuntos
Peixes/genética , Organismos Hermafroditas/genética , Espermatogênese/genética , Testículo/crescimento & desenvolvimento , Animais , Proteínas de Peixes/genética , Peixes/crescimento & desenvolvimento , Regulação da Expressão Gênica no Desenvolvimento/genética , Células Germinativas/metabolismo , Organismos Hermafroditas/crescimento & desenvolvimento , Masculino , RNA-Seq , Diferenciação Sexual/genética , Análise de Célula Única , Testículo/patologia
6.
BMC Plant Biol ; 21(1): 468, 2021 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-34645403

RESUMO

BACKGROUND: The fragrant flower plant Osmanthus fragrans has an extremely rare androdioecious breeding system displaying the occurrence of males and hermaphrodites in a single population, which occupies a crucial intermediate stage in the evolutionary transition between hermaphroditism and dioecy. However, the molecular mechanism of androdioecy plant is very limited and still largely unknown. RESULTS: Here, we used SWATH-MS-based quantitative approach to study the proteome changes between male and hermaphroditic O. fragrans pistils. A total of 428 proteins of diverse functions were determined to show significant abundance changes including 210 up-regulated and 218 down-regulated proteins in male compared to hermaphroditic pistils. Functional categorization revealed that the differentially expressed proteins (DEPs) primarily distributed in the carbohydrate metabolism, secondary metabolism as well as signaling cascades. Further experimental analysis showed the substantial carbohydrates accumulation associated with promoted net photosynthetic rate and water use efficiency were observed in purplish red pedicel of hermaphroditic flower compared with green pedicel of male flower, implicating glucose metabolism serves as nutritional modulator for the differentiation of male and hermaphroditic flower. Meanwhile, the entire upregulation of secondary metabolism including flavonoids, isoprenoids and lignins seem to protect and maintain the male function in male flowers, well explaining important feature of androdioecy that aborted pistil of a male flower still has a male function. Furthermore, nine selected DEPs were validated via gene expression analysis, suggesting an extra layer of post-transcriptional regulation occurs during O. fragrans floral development. CONCLUSION: Taken together, our findings represent the first SWATH-MS-based proteomic report in androdioecy plant O. fragrans, which reveal carbohydrate metabolism, secondary metabolism and post-transcriptional regulation contributing to the androdioecy breeding system and ultimately extend our understanding on genetic basis as well as the industrialization development of O. fragrans.


Assuntos
Metabolismo dos Carboidratos/genética , Flores/crescimento & desenvolvimento , Flores/genética , Oleaceae/crescimento & desenvolvimento , Oleaceae/genética , Oleaceae/metabolismo , Reprodução/genética , Reprodução/fisiologia , Evolução Biológica , China , Regulação da Expressão Gênica de Plantas , Variação Genética , Organismos Hermafroditas/genética , Organismos Hermafroditas/crescimento & desenvolvimento , Organismos Hermafroditas/metabolismo , Fenótipo , Proteômica
7.
Dev Biol ; 478: 122-132, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34224682

RESUMO

Sexual systems are surprisingly diverse, considering the ubiquity of sexual reproduction. Sequential hermaphroditism, the ability of an individual to change sex, has emerged multiple times independently across the animal kingdom. In molluscs, repeated shifts between ancestrally separate sexes and hermaphroditism are generally found at the level of family and above, suggesting recruitment of deeply conserved mechanisms. Despite this, molecular mechanisms of sexual development are poorly known. In molluscs with separate sexes, endocrine disrupting toxins bind the retinoid X receptor (RXR), activating ectopic male development in females, suggesting the retinoid pathway as a candidate controlling sexual transitions in sequential hermaphrodites. We therefore tested the role of retinoic acid signaling in sequentially hermaphroditic Crepidula snails, which develop first into males, then change sex, maturing into females. We show that retinoid agonists induce precocious penis growth in juveniles and superimposition of male development in females. Combining RXR antagonists with retinoid agonists significantly reduces penis length in induced juveniles, while similar treatments using retinoic acid receptor (RAR) antagonists increase penis length. Transcripts of both receptors are expressed in the induced penis. Our findings therefore show that retinoid signaling can initiate molluscan male genital development, and regulate penis length. Further, we show that retinoids induce ectopic male development in multiple Crepidula species. Species-specific influence of conspecific induction of sexual transitions correlates with responsiveness to retinoids. We propose that retinoid signaling plays a conserved role in molluscan male development, and that shifts in the timing of retinoid signaling may have been important for the origins of sequential hermaphroditism within molluscs.


Assuntos
Organismos Hermafroditas/crescimento & desenvolvimento , Retinoides/metabolismo , Caramujos/crescimento & desenvolvimento , Caramujos/metabolismo , Animais , Família 26 do Citocromo P450/genética , Feminino , Organismos Hermafroditas/genética , Organismos Hermafroditas/metabolismo , Masculino , Pênis/crescimento & desenvolvimento , Pênis/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptores do Ácido Retinoico/agonistas , Receptores do Ácido Retinoico/antagonistas & inibidores , Receptores do Ácido Retinoico/genética , Receptores do Ácido Retinoico/metabolismo , Receptores X de Retinoides/agonistas , Receptores X de Retinoides/genética , Receptores X de Retinoides/metabolismo , Transdução de Sinais , Caramujos/anatomia & histologia , Caramujos/genética , Especificidade da Espécie , Tretinoína/metabolismo , Compostos de Trialquitina/farmacologia
8.
Sci Rep ; 11(1): 14481, 2021 07 14.
Artigo em Inglês | MEDLINE | ID: mdl-34262087

RESUMO

Anesthetic isoflurane has been reported to induce toxicity. However, the effects of isoflurane on fecundity remain largely unknown. We established a system in C. elegans to investigate the effects of isoflurane on oogenesis. Synchronized L4 stage C. elegans were treated with 7% isoflurane for 4 h. Dead cells, ROS, embryos, and unfertilized eggs laid by hermaphrodites were measured by fluorescence imaging and counting. The C. elegans with losses of ced-3, cep-1, abl-1, male C. elegans, and oxidative stress inhibitor N-acetyl-cysteine were used in the interaction studies. We found that isoflurane decreased the numbers of embryos and unfertilized eggs and increased the levels of dead cells and ROS in C. elegans. The isoflurane-induced impairment of oogenesis was associated with abl-1, ced-3, but not cep-1. N-acetyl-cysteine attenuated the isoflurane-induced impairment of oogenesis in C. elegans. Mating with male C. elegans did not attenuate the isoflurane-induced changes in oogenesis. These findings suggest that isoflurane may impair oogenesis through abl-1- and ced-3-associated, but not cep-1-associated, germ cell apoptosis and oxidative stress, pending further investigation. These studies will promote more research to determine the potential effects of anesthesia on fecundity.


Assuntos
Apoptose/efeitos dos fármacos , Caenorhabditis elegans/efeitos dos fármacos , Isoflurano/toxicidade , Oogênese/efeitos dos fármacos , Anestésicos Inalatórios/toxicidade , Animais , Caenorhabditis elegans/citologia , Caenorhabditis elegans/embriologia , Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/genética , Caspases/genética , Embrião não Mamífero/efeitos dos fármacos , Feminino , Organismos Hermafroditas , Masculino , Estresse Oxidativo/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-abl/genética , Espécies Reativas de Oxigênio/metabolismo , Proteína Supressora de Tumor p53/genética
9.
Nat Commun ; 12(1): 3263, 2021 05 31.
Artigo em Inglês | MEDLINE | ID: mdl-34059684

RESUMO

A fundamental question in medical genetics is how the genetic background modifies the phenotypic outcome of mutations. We address this question by focusing on the seam cells, which display stem cell properties in the epidermis of Caenorhabditis elegans. We demonstrate that a putative null mutation in the GATA transcription factor egl-18, which is involved in seam cell fate maintenance, is more tolerated in the CB4856 isolate from Hawaii than the lab reference strain N2 from Bristol. We identify multiple quantitative trait loci (QTLs) underlying the difference in phenotype expressivity between the two isolates. These QTLs reveal cryptic genetic variation that reinforces seam cell fate through potentiating Wnt signalling. Within one QTL region, a single amino acid deletion in the heat shock protein HSP-110 in CB4856 is sufficient to modify Wnt signalling and seam cell development, highlighting that natural variation in conserved heat shock proteins can shape phenotype expressivity.


Assuntos
Proteínas de Caenorhabditis elegans/genética , Diferenciação Celular/genética , Células Epidérmicas/fisiologia , Fatores de Transcrição GATA/genética , Proteínas de Choque Térmico HSP110/genética , Células-Tronco/fisiologia , Animais , Caenorhabditis elegans , Proteínas de Caenorhabditis elegans/metabolismo , Fatores de Transcrição GATA/metabolismo , Estudos de Associação Genética , Técnicas Genéticas , Variação Genética , Proteínas de Choque Térmico HSP110/metabolismo , Organismos Hermafroditas , Masculino , Mutação , Locos de Características Quantitativas , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Via de Sinalização Wnt/genética
10.
Artigo em Inglês | MEDLINE | ID: mdl-34091708

RESUMO

Photoperiod is a reliable cue to regulate growth and reproduction for seasonal adaptation. Although photoperiodism has been well studied in Chordata and Arthropoda, less is known about Mollusca. We examined photoperiodic effects on egg laying, body size, gonad-somatic index, oocyte size and relative amounts of caudodorsal cell hormone mRNA in individual rearing conditions in the pond snail Lymnaea stagnalis. Twenty-five weeks after hatching, the percentages of egg-laying snails under a photoperiod of 12 h light and 12 h darkness (12L:12D) were significantly smaller than those under longer days. The total numbers of eggs and egg masses under 12L:12D were significantly smaller than those under longer days. Significant differences between 16L:8D and 12L:12D were not observed in the soft body and ovotestis weight, and the gonad-somatic index. Photoperiodic effects were also not observed in oocyte diameters twenty-two weeks after hatching. Twenty-seven weeks after hatching amounts of caudodorsal cell hormone mRNA were significantly lower in the cerebral ganglia with commissure under 12L:12D than 16L:8D. L. stagnalis exhibited a clear photoperiodic response in egg laying and the amount of caudodorsal cell hormone mRNA, but not in gonadal development. Under 12L:12D suppression of caudodorsal cell hormone expression might suppress egg laying.


Assuntos
Gônadas/crescimento & desenvolvimento , Hormônios de Invertebrado/biossíntese , Lymnaea/anatomia & histologia , Lymnaea/fisiologia , Oviposição/fisiologia , Fotoperíodo , Animais , Organismos Hermafroditas/fisiologia
11.
Sci Rep ; 11(1): 11117, 2021 05 27.
Artigo em Inglês | MEDLINE | ID: mdl-34045599

RESUMO

Vertebrates usually exhibit gonochorism, whereby their sex is fixed throughout their lifetime. However, approximately 500 species (~ 2%) of extant teleost fishes change sex during their lifetime. Although phylogenetic and evolutionary ecological studies have recently revealed that the extant sequential hermaphroditism in teleost fish is derived from gonochorism, the evolution of this transsexual ability remains unclear. We revealed in a previous study that the tunica of the ovaries of several protogynous hermaphrodite groupers contain functional androgen-producing cells, which were previously unknown structures in the ovaries of gonochoristic fishes. Additionally, we demonstrated that these androgen-producing cells play critical roles in initiating female-to-male sex change in several grouper species. In the present study, we widened the investigation to include 7 genera and 18 species of groupers and revealed that representatives from most major clades of extant groupers commonly contain these androgen-producing cells, termed testicular-inducing steroidogenic (TIS) cells. Our findings suggest that groupers acquired TIS cells in the tunica of the gonads for successful sex change during their evolution. Thus, TIS cells trigger the evolution of sex change in groupers.


Assuntos
Organismos Hermafroditas/fisiologia , Perciformes/fisiologia , Processos de Determinação Sexual/fisiologia , Testículo/fisiologia , Androgênios/metabolismo , Animais , Feminino , Masculino
12.
Genetics ; 217(1): 1-14, 2021 03 03.
Artigo em Inglês | MEDLINE | ID: mdl-33683352

RESUMO

Posttranscriptional regulation of gene expression, typically effected by RNA-binding proteins, microRNAs (miRNAs), and translation initiation factors, is essential for normal germ cell function. Numerous miRNAs have been detected in the germline; however, the functions of specific miRNAs remain largely unknown. Functions of miRNAs have been difficult to determine as miRNAs often modestly repress target mRNAs and are suggested to sculpt or fine tune gene expression to allow for the robust expression of cell fates. In Caenorhabditis elegans hermaphrodites, cell fate decisions are made for germline sex determination during larval development when sperm are generated in a short window before the switch to oocyte production. Here, analysis of newly generated mir-44 family mutants has identified a family of miRNAs that modulate the germline sex determination pathway in C. elegans. Mutants with the loss of mir-44 and mir-45 produce fewer sperm, showing both a delay in the specification and formation of sperm as well as an early termination of sperm specification accompanied by a premature switch to oocyte production. mir-44 and mir-45 are necessary for the normal period of fog-1 expression in larval development. Through genetic analysis, we find that mir-44 and mir-45 may act upstream of fbf-1 and fem-3 to promote sperm specification. Our research indicates that the mir-44 family promotes sperm cell fate specification during larval development and identifies an additional posttranscriptional regulator of the germline sex determination pathway.


Assuntos
Células Germinativas/metabolismo , MicroRNAs/genética , Espermatogênese , Animais , Caenorhabditis elegans , Regulação da Expressão Gênica no Desenvolvimento , Células Germinativas/citologia , Organismos Hermafroditas/genética , Organismos Hermafroditas/crescimento & desenvolvimento , MicroRNAs/metabolismo , Processos de Determinação Sexual
13.
Evolution ; 75(5): 1011-1029, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33675041

RESUMO

Self-fertilization commonly occurs in hermaphroditic species, either occasionally or as the main reproductive mode. It strongly affects the genetic functioning of a population by increasing homozygosity and genetic drift and reducing the effectiveness of recombination. Balancing selection is a form of selection that maintains polymorphism, which has been extensively studied in outcrossing species. Yet, despite recent developments, the analysis of balancing selection in partially selfing species is limited to specific cases and a general treatment is still lacking. In particular, it is unclear whether selfing globally reduced the efficacy of balancing selection as in the well-known case of overdominance. I provide a unifying framework, quantify how selfing affects the maintenance of polymorphism and the efficacy of the different form of balancing selection, and show that they can be classified into two main categories: overdominance-like selection (including true overdominance, selection variable in space and time, and antagonistic selection), which is strongly affected by selfing, and negative frequency dependent selection, which is barely affected by selfing, even at multiple loci. I also provide simple analytical results for all cases under the assumption of weak selection. This framework provides theoretical background to analyze the genomic signature of balancing selection in partially selfing species. It also sheds new light on the evolution of selfing species, including the evolution of selfing syndrome, the interaction with pathogens, and the evolutionary fate of selfing lineages.


Assuntos
Organismos Hermafroditas/genética , Seleção Genética , Autofertilização/genética , Animais , Modelos Genéticos , Plantas/genética , Polimorfismo Genético
14.
J Neurosci Res ; 99(5): 1191-1206, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33559247

RESUMO

Astrocytes modulate synaptic transmission; yet, it remains unclear how glia influence complex behaviors. Here, we explore the effects of Caenorhabditis elegans astrocyte-like cephalic glia (CEPglia ) and the glia-specific bHLH transcription factor HLH-17 on mating behavior and the defecation motor program (DMP). In C. elegans, male mating has been explicitly described through the male tail circuit and is characterized by coordination of multiple independent behaviors to ensure that copulation is achieved. Furthermore, the sex-specific male mating circuitry shares similar components with the DMP, which is complex and rhythmic, and requires a fixed sequence of behaviors to be activated periodically. We found that loss of CEPglia reduced persistence in executing mating behaviors and hindered copulation, while males that lacked HLH-17 demonstrated repetitive prodding behavior that increased the time spent in mating but did not hinder copulation. During the DMP, we found that posterior body wall contractions (pBocs) and enteric muscle contractions (EMCs) were differentially affected by loss of HLH-17 or CEPglia in males and hermaphrodites. pBocs and EMCs required HLH-17 activity in both sexes, whereas loss of CEPglia alone did not affect DMP in males. Our data suggest that CEPglia mediate complex behaviors by signaling to the GABAergic DVB neuron, and that HLH-17 activity influences those discrete steps within those behaviors. Collectively, these data provide evidence of glia as a link in cooperative regulation of complex and rhythmic behavior that, in C. elegans links circuitry in the head and the tail.


Assuntos
Proteínas de Caenorhabditis elegans/metabolismo , Copulação/fisiologia , Neurônios GABAérgicos/fisiologia , Organismos Hermafroditas/fisiologia , Locomoção/fisiologia , Neuroglia/fisiologia , Fatores de Transcrição/metabolismo , Animais , Animais Geneticamente Modificados , Caenorhabditis elegans , Proteínas de Caenorhabditis elegans/genética , Feminino , Masculino , Fatores de Transcrição/genética
15.
Curr Biol ; 31(6): 1277-1283.e5, 2021 03 22.
Artigo em Inglês | MEDLINE | ID: mdl-33472050

RESUMO

Evolutionary transitions from hermaphroditism to dioecy have been common in flowering plants,1,2 but recent analysis also points to frequent reversions from dioecy to hermaphroditism.2-4 Here, we use experimental evolution to expose a mechanism for such reversions, validating an explanation for the scattered phylogenetic distribution of dioecy. We removed males from dioecious populations of the wind-pollinated plant Mercurialis annua and allowed natural selection to act on the remaining females that occasionally produced male flowers; such "leaky" sex expression is common in both males and females of dioecious plants.5 Over the course of four generations, females evolved a 23-fold increase in average male flower production. This phenotypic masculinization of females coincided with the evolution of partial self-fertilization, high average seed set in the continued absence of males, and a capacity to sire progeny when males were re-introduced into their populations. Our study thus validates a mechanism for the rapid dissolution of dioecy and the evolution of functional hermaphroditism under conditions that may frequently occur during periods of low population density, repeated colonization, or range expansion.6,7 Our results illustrate the power of natural selection, acting in replicated experimental populations, to bring about transitions in the mating behavior of plants.


Assuntos
Evolução Biológica , Organismos Hermafroditas , Magnoliopsida , Filogenia , Reprodução , Solubilidade
16.
Dev Biol ; 470: 10-20, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33160939

RESUMO

VAMP/synaptobrevin-associated protein B (VAP-B) is a type II ER membrane protein, but its N-terminal MSP domain (MSPd) can be cleaved and secreted. Mutations preventing the cleavage and secretion of MSPd have been implicated in cases of human neurodegenerative diseases. The site of VAP cleavage and the tissues capable in releasing the processed MSPd are not understood. In this study, we analyze the C. elegans VAP-B homolog, VPR-1, for its processing and secretion from the intestine. We show that intestine-specific expression of an N-terminally FLAG-tagged VPR-1 rescues underdeveloped gonad and sterility defects in vpr-1 null hermaphrodites. Immunofluorescence studies reveal that the tagged intestinal expressed VPR-1 is present at the distal gonad. Mass spectrometry analysis of a smaller product of the N-terminally tagged VPR-1 identifies a specific cleavage site at Leu156. Mutation of the leucine results in loss of gonadal MSPd signal and reduced activity of the mutant VPR-1. Thus, we report for the first time the cleavage site of VPR-1 and provide direct evidence that intestinally expressed VPR-1 can be released and signal in the distal gonad. These results establish the foundation for further exploration of VAP cleavage, MSPd secretion, and non-cell-autonomous signaling in development and diseases.


Assuntos
Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/metabolismo , Proteínas de Helminto/metabolismo , Proteínas de Membrana/metabolismo , Animais , Animais Geneticamente Modificados , Caenorhabditis elegans/embriologia , Caenorhabditis elegans/genética , Caenorhabditis elegans/crescimento & desenvolvimento , Proteínas de Caenorhabditis elegans/química , Proteínas de Caenorhabditis elegans/genética , Retículo Endoplasmático/metabolismo , Genes de Helmintos , Gônadas/química , Gônadas/crescimento & desenvolvimento , Gônadas/metabolismo , Proteínas de Helminto/química , Organismos Hermafroditas/genética , Organismos Hermafroditas/metabolismo , Organismos Hermafroditas/fisiologia , Infertilidade , Intestinos/citologia , Intestinos/fisiologia , Leucina/metabolismo , Proteínas de Membrana/química , Proteínas de Membrana/genética , Fenótipo , Mutação Puntual , Domínios Proteicos , Processamento de Proteína Pós-Traducional
17.
Mol Genet Genomics ; 296(1): 1-20, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32888055

RESUMO

Forward genetics is a powerful tool to unravel molecular mechanisms of diverse biological processes. The success of genetic screens primarily relies on the ease of genetic manipulation of an organism and the availability of a plethora of genetic tools. The roundworm Caenorhabditis elegans has been one of the favorite models for genetic studies due to its hermaphroditic lifestyle, ease of maintenance, and availability of various genetic manipulation tools. The strength of C. elegans genetics is highlighted by the leading role of this organism in the discovery of several conserved biological processes. In this review, the principles and strategies for forward genetics in C. elegans are discussed. Further, the recent advancements that have drastically accelerated the otherwise time-consuming process of mutation identification, making forward genetic screens a method of choice for understanding biological functions, are discussed. The emphasis of the review has been on providing practical and conceptual pointers for designing genetic screens that will identify mutations, specifically disrupting the biological processes of interest.


Assuntos
Proteínas de Caenorhabditis elegans/genética , Caenorhabditis elegans/genética , Genoma Helmíntico , Organismos Hermafroditas/genética , Mutagênese , Animais , Mapeamento Cromossômico/métodos , Cruzamentos Genéticos , Feminino , Edição de Genes/métodos , Ensaios de Triagem em Larga Escala , Masculino , Mutação , Polimorfismo de Nucleotídeo Único , Interferência de RNA
18.
Commun Biol ; 4(1): 1018, 2021 08 31.
Artigo em Inglês | MEDLINE | ID: mdl-34465863

RESUMO

Dioecious species are a hallmark of the animal kingdom, with opposing sexes responding differently to identical sensory cues. Here, we study the response of C. elegans to the small-molecule pheromone, ascr#8, which elicits opposing behavioral valences in each sex. We identify a novel neuropeptide-neuropeptide receptor (NP/NPR) module that is active in males, but not in hermaphrodites. Using a novel paradigm of neuropeptide rescue that we established, we leverage bacterial expression of individual peptides to rescue the sex-specific response to ascr#8. Concurrent biochemical studies confirmed individual FLP-3 peptides differentially activate two divergent receptors, NPR-10 and FRPR-16. Interestingly, the two of the peptides that rescued behavior in our feeding paradigm are related through a conserved threonine, suggesting that a specific NP/NPR combination sets a male state, driving the correct behavioral valence of the ascr#8 response. Receptor expression within pre-motor neurons reveals novel coordination of male-specific and core locomotory circuitries.


Assuntos
Caenorhabditis elegans/fisiologia , Organismos Hermafroditas/fisiologia , Locomoção , Receptores de Neuropeptídeos/genética , Animais , Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans , Proteínas de Transporte , Organismos Hermafroditas/genética , Locomoção/efeitos dos fármacos , Masculino , Receptores de Neuropeptídeos/metabolismo
19.
Mol Genet Genomics ; 296(6): 1323-1335, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34609588

RESUMO

Sex form is one of the most important characteristics in papaya cultivation in which hermaphrodite is the preferable form. Self-pollination of H*-TSS No.7, an inbred line derived from a rare X chromosome mutant SR*, produced all-hermaphrodite progeny. The recessive lethal allele controlling the all-hermaphrodite phenomenon was proposed to be the recessive Germination suppressor (gs) locus. This study employed next-generation sequencing technology and genome comparison to identify the candidate Gs gene. One specific gene, monodehydroascorbate reductase 4 (MDAR4) harboring a unique polymorphic 3 bp deletion in H*-TSS No.7 was identified. The function of MDAR4 is known to be involved in the hydrogen peroxide (H2O2) scavenging pathway and is associated with seed germination. Furthermore, MDAR4 showed higher expression in the imbibed seeds than that in the dry seeds indicating its potential role in the seed germination. Perhaps this is the very first report providing the evidences that MDAR4 is the candidate of Gs locus in H*-TSS No.7. In addition, Gs allele-specific markers were developed which would be facilitated for breeding all-hermaphrodite lines.


Assuntos
Carica/genética , Cromossomos de Plantas/genética , Organismos Hermafroditas/genética , NADH NADPH Oxirredutases/genética , Genoma de Planta/genética , Germinação/genética , Peróxido de Hidrogênio/metabolismo , Polinização/genética , Polinização/fisiologia , Sementes/crescimento & desenvolvimento , Deleção de Sequência/genética
20.
J Evol Biol ; 34(1): 49-59, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32242998

RESUMO

Extreme inbreeding is expected to reduce the incidence of hybridization, serving as a prezygotic barrier. Mangrove rivulus is a small killifish that reproduces predominantly by self-fertilization, producing highly homozygous lines throughout its geographic range. The Bahamas and Caribbean are inhabited by two highly diverged phylogeographic lineages of mangrove rivulus, Kryptolebias marmoratus and a 'Central clade' closely related to K. hermaphroditus from Brazil. The two lineages are largely allopatric, but recently were found in syntopy on San Salvador, Bahamas, where a single hybrid was reported. To better characterize the degree of hybridization and the possibility of secondary introgression, here we conducted a detailed genetic analysis of the contact zone on San Salvador. Two mixed populations were identified, one of which contained sexually mature hybrids. The distribution of heterozygosity at diagnostic microsatellite loci in hybrids showed that one of these hybrids was an immediate offspring from the K. marmoratus x Central clade cross, whereas the remaining five hybrids were products of reproduction by self-fertilization for 1-3 generations following the initial cross. Two hybrids had mitochondrial haplotypes of K. marmoratus and the remaining four hybrids had a haplotype of the Central clade, indicating that crosses go in both directions. In hybrids, alleles of parental lineages were represented in equal proportions suggesting lack of recent backcrossing to either of the parental lineages. However, sympatric populations of two lineages were less diverged than allopatric populations, consistent with introgression. Results are discussed in terms of applicability of the biological species concept for isogenic, effectively clonal, organisms.


Assuntos
Fundulidae/genética , Introgressão Genética , Autofertilização , Simpatria , Animais , Bahamas , Feminino , Fundulidae/classificação , Organismos Hermafroditas , Masculino , Filogeografia
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