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Smith M, Lesperance M, Herrmann A, Vernooy S, Cherian A, Kivlehan E, Whipple L, Portman DS, Mason DA. Two C. elegans DM domain proteins, DMD-3 and MAB-3, function in late stages of male somatic gonad development. Dev Biol 2024; 514:50-65. [PMID: 38880276 DOI: 10.1016/j.ydbio.2024.06.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 05/30/2024] [Accepted: 06/13/2024] [Indexed: 06/18/2024]
Abstract
To bring about sexual dimorphism in form, information from the sex determination pathway must trigger sex-specific modifications in developmental programs. DM-domain encoding genes have been found to be involved in sex determination in a multitude of animals, often at the level of male somatic gonad formation. Here we report our findings that the DM-domain transcription factors MAB-3 and DMD-3 function together in multiple steps during the late stages of C. elegans male somatic gonad development. Both mab-3 and dmd-3 are expressed in the linker cell and hindgut of L4 males and dmd-3 is also expressed in presumptive vas deferens cells. Furthermore, dmd-3, but not mab-3, expression in the linker cell is downstream of nhr-67, a nuclear hormone receptor that was previously shown to control late stages of linker cell migration. In mab-3; dmd-3 double mutant males, the last stage of linker cell migration is partially defective, resulting in aberrant linker cell shapes and often a failure of the linker cell to complete its migration to the hindgut. When mab-3; dmd-3 double mutant linker cells do complete their migration, they fail to be engulfed by the hindgut, indicating that dmd-3 and mab-3 activity are essential for this process. Furthermore, linker cell death and clearance are delayed in mab-3; dmd-3 double mutants, resulting in the linker cell persisting into adulthood. Finally, DMD-3 and MAB-3 function to activate expression of the bZIP transcription factor encoding gene zip-5 and downregulate the expression of the zinc metalloprotease ZMP-1 in the linker cell. Taken together, these results demonstrate a requirement for DM-domain transcription factors in controlling C. elegans male gonad formation, supporting the notion that the earliest DM-domain genes were involved in male somatic gonad development in the last common ancestor of the bilaterians.
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Affiliation(s)
- Michele Smith
- Biology Department, Siena College, Loudonville, NY, 12211, USA
| | | | - Alyssa Herrmann
- Biology Department, Siena College, Loudonville, NY, 12211, USA
| | | | - Asher Cherian
- Biology Department, Siena College, Loudonville, NY, 12211, USA
| | - Emily Kivlehan
- Biology Department, Siena College, Loudonville, NY, 12211, USA
| | - Lauren Whipple
- Biology Department, Siena College, Loudonville, NY, 12211, USA
| | - Douglas S Portman
- Department of Biomedical Genetics, University of Rochester, Rochester, NY, 14642, USA; Department of Neuroscience, University of Rochester, Rochester, NY, 14642, USA; Department of Biology, University of Rochester, Rochester, NY, 14642, USA
| | - D Adam Mason
- Biology Department, Siena College, Loudonville, NY, 12211, USA; Department of Biomedical Genetics, University of Rochester, Rochester, NY, 14642, USA.
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2
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Wan Y, Macias LH, Garcia LR. Unraveling the hierarchical structure of posture and muscle activity changes during mating of Caenorhabditis elegans. PNAS NEXUS 2024; 3:pgae032. [PMID: 38312221 PMCID: PMC10837012 DOI: 10.1093/pnasnexus/pgae032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 01/16/2024] [Indexed: 02/06/2024]
Abstract
One goal of neurobiology is to explain how decision-making in neuromuscular circuits produces behaviors. However, two obstacles complicate such efforts: individual behavioral variability and the challenge of simultaneously assessing multiple neuronal activities during behavior. Here, we circumvent these obstacles by analyzing whole animal behavior from a library of Caenorhabditis elegans male mating recordings. The copulating males express the GCaMP calcium sensor in the muscles, allowing simultaneous recording of posture and muscle activities. Our library contains wild type and males with selective neuronal desensitization in serotonergic neurons, which include male-specific posterior cord motor/interneurons and sensory ray neurons that modulate mating behavior. Incorporating deep learning-enabled computer vision, we developed a software to automatically quantify posture and muscle activities. By modeling, the posture and muscle activity data are classified into stereotyped modules, with the behaviors represented by serial executions and transitions among the modules. Detailed analysis of the modules reveals previously unidentified subtypes of the male's copulatory spicule prodding behavior. We find that wild-type and serotonergic neurons-suppressed males had different usage preferences for those module subtypes, highlighting the requirement of serotonergic neurons in the coordinated function of some muscles. In the structure of the behavior, bi-module repeats coincide with most of the previously described copulation steps, suggesting a recursive "repeat until success/give up" program is used for each step during mating. On the other hand, the transition orders of the bi-module repeats reveal the sub-behavioral hierarchy males employ to locate and inseminate hermaphrodites.
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Affiliation(s)
- Yufeng Wan
- Department of Biology, Texas A&M University, 3258 TAMU, College Station, TX 77843, USA
| | - Luca Henze Macias
- Department of Biology, Texas A&M University, 3258 TAMU, College Station, TX 77843, USA
| | - Luis Rene Garcia
- Department of Biology, Texas A&M University, 3258 TAMU, College Station, TX 77843, USA
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3
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Roux AE, Yuan H, Podshivalova K, Hendrickson D, Kerr R, Kenyon C, Kelley D. Individual cell types in C. elegans age differently and activate distinct cell-protective responses. Cell Rep 2023; 42:112902. [PMID: 37531250 DOI: 10.1016/j.celrep.2023.112902] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 05/17/2023] [Accepted: 07/14/2023] [Indexed: 08/04/2023] Open
Abstract
Aging is characterized by a global decline in physiological function. However, by constructing a complete single-cell gene expression atlas, we find that Caenorhabditis elegans aging is not random in nature but instead is characterized by coordinated changes in functionally related metabolic, proteostasis, and stress-response genes in a cell-type-specific fashion, with downregulation of energy metabolism being the only nearly universal change. Similarly, the rates at which cells age differ significantly between cell types. In some cell types, aging is characterized by an increase in cell-to-cell variance, whereas in others, variance actually decreases. Remarkably, multiple resilience-enhancing transcription factors known to extend lifespan are activated across many cell types with age; we discovered new longevity candidates, such as GEI-3, among these. Together, our findings suggest that cells do not age passively but instead react strongly, and individualistically, to events that occur during aging. This atlas can be queried through a public interface.
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Affiliation(s)
| | - Han Yuan
- Calico Life Sciences LLC, South San Francisco, CA 94080, USA
| | | | | | - Rex Kerr
- Calico Life Sciences LLC, South San Francisco, CA 94080, USA
| | - Cynthia Kenyon
- Calico Life Sciences LLC, South San Francisco, CA 94080, USA.
| | - David Kelley
- Calico Life Sciences LLC, South San Francisco, CA 94080, USA.
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4
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Godini R, Pocock R. Characterization of the Doublesex/MAB-3 transcription factor DMD-9 in Caenorhabditis elegans. G3 (BETHESDA, MD.) 2023; 13:jkac305. [PMID: 36454093 PMCID: PMC9911054 DOI: 10.1093/g3journal/jkac305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 09/30/2022] [Accepted: 11/10/2022] [Indexed: 12/05/2022]
Abstract
DMD-9 is a Caenorhabditis elegans Doublesex/MAB-3 Domain transcription factor (TF) of unknown function. Single-cell transcriptomics has revealed that dmd-9 is highly expressed in specific head sensory neurons, with lower levels detected in non-neuronal tissues (uterine cells and sperm). Here, we characterized endogenous dmd-9 expression and function in hermaphrodites and males to identify potential sexually dimorphic roles. In addition, we dissected the trans- and cis-regulatory mechanisms that control DMD-9 expression in neurons. Our results show that of the 22 neuronal cell fate reporters we assessed in DMD-9-expressing neurons, only the neuropeptide-encoding flp-19 gene is cell-autonomously regulated by DMD-9. Further, we did not identify defects in behaviors mediated by DMD-9 expressing neurons in dmd-9 mutants. We found that dmd-9 expression in neurons is regulated by 4 neuronal fate regulatory TFs: ETS-5, EGL-13, CHE-1, and TTX-1. In conclusion, our study characterized the DMD-9 expression pattern and regulatory logic for its control. The lack of detectable phenotypes in dmd-9 mutant animals suggests that other proteins compensate for its loss.
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Affiliation(s)
- Rasoul Godini
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, Victoria 3800, Australia
| | - Roger Pocock
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, Victoria 3800, Australia
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5
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Han C, Peng Q, Su X, Xing L, Ji X, Pan Y. A male-specific doublesex isoform reveals an evolutionary pathway of sexual development via distinct alternative splicing mechanisms. Commun Biol 2022; 5:728. [PMID: 35869175 PMCID: PMC9307624 DOI: 10.1038/s42003-022-03664-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 06/29/2022] [Indexed: 11/30/2022] Open
Abstract
The doublesex/mab-3 related transcription factor (Dmrt) genes regulate sexual development in metazoans. Studies of the doublesex (dsx) gene in insects, in particular Drosophila melanogaster, reveal that alternative splicing of dsx generates sex-specific Dsx isoforms underlying sexual differentiation. Such a splicing-based mechanism underlying sex-specific Dmrt function is thought to be evolved from a transcription-based mechanism used in non-insect species, but how such transition occurs during evolution is not known. Here we identified a male-specific dsx transcript (dsxM2) through intron retention (IR), in addition to previously identified dsxM and dsxF transcripts through alternative polyadenylation (APA) with mutually exclusive exons. We found that DsxM2 had similarly masculinizing function as DsxM. We also found that the IR-based mechanism generating sex-specific dsx transcripts was conserved from flies to cockroaches. Further analysis of these dsx transcripts suggested an evolutionary pathway from sexually monomorphic to sex-specific dsx via the sequential use of IR-based and APA-based alternative splicing. An ancestral male-specific doublesex isoform, dsxM2, is identified via intron retention, with a masculinizing function weaker than the modern dsxM
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6
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Casado-Navarro R, Serrano-Saiz E. DMRT Transcription Factors in the Control of Nervous System Sexual Differentiation. Front Neuroanat 2022; 16:937596. [PMID: 35958734 PMCID: PMC9361473 DOI: 10.3389/fnana.2022.937596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 06/15/2022] [Indexed: 11/13/2022] Open
Abstract
Sexual phenotypic differences in the nervous system are one of the most prevalent features across the animal kingdom. The molecular mechanisms responsible for sexual dimorphism throughout metazoan nervous systems are extremely diverse, ranging from intrinsic cell autonomous mechanisms to gonad-dependent endocrine control of sexual traits, or even extrinsic environmental cues. In recent years, the DMRT ancient family of transcription factors has emerged as being central in the development of sex-specific differentiation in all animals in which they have been studied. In this review, we provide an overview of the function of Dmrt genes in nervous system sexual regulation from an evolutionary perspective.
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7
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Goodwin SF, Hobert O. Molecular Mechanisms of Sexually Dimorphic Nervous System Patterning in Flies and Worms. Annu Rev Cell Dev Biol 2021; 37:519-547. [PMID: 34613817 DOI: 10.1146/annurev-cellbio-120319-115237] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Male and female brains display anatomical and functional differences. Such differences are observed in species across the animal kingdom, including humans, but have been particularly well-studied in two classic animal model systems, the fruit fly Drosophila melanogaster and the nematode Caenorhabditis elegans. Here we summarize recent advances in understanding how the worm and fly brain acquire sexually dimorphic features during development. We highlight the advantages of each system, illustrating how the precise anatomical delineation of sexual dimorphisms in worms has enabled recent analysis into how these dimorphisms become specified during development, and how focusing on sexually dimorphic neurons in the fly has enabled an increasingly detailed understanding of sex-specific behaviors.
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Affiliation(s)
- Stephen F Goodwin
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford OX1 3SR, United Kingdom;
| | - Oliver Hobert
- Department of Biological Sciences and Howard Hughes Medical Institute, Columbia University, New York, NY 10027, USA;
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8
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Evans KS, van Wijk MH, McGrath PT, Andersen EC, Sterken MG. From QTL to gene: C. elegans facilitates discoveries of the genetic mechanisms underlying natural variation. Trends Genet 2021; 37:933-947. [PMID: 34229867 DOI: 10.1016/j.tig.2021.06.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 06/01/2021] [Accepted: 06/03/2021] [Indexed: 11/15/2022]
Abstract
Although many studies have examined quantitative trait variation across many species, only a small number of genes and thereby molecular mechanisms have been discovered. Without these data, we can only speculate about evolutionary processes that underlie trait variation. Here, we review how quantitative and molecular genetics in the nematode Caenorhabditis elegans led to the discovery and validation of 37 quantitative trait genes over the past 15 years. Using these data, we can start to make inferences about evolution from these quantitative trait genes, including the roles that coding versus noncoding variation, gene family expansion, common versus rare variants, pleiotropy, and epistasis play in trait variation across this species.
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Affiliation(s)
- Kathryn S Evans
- Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA; Interdisciplinary Biological Sciences Program, Northwestern University, Evanston, IL 60208, USA
| | - Marijke H van Wijk
- Laboratory of Nematology, Wageningen University and Research, 6708 PB, Wageningen, The Netherlands
| | - Patrick T McGrath
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Erik C Andersen
- Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA.
| | - Mark G Sterken
- Laboratory of Nematology, Wageningen University and Research, 6708 PB, Wageningen, The Netherlands.
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9
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Bayer EA, Stecky RC, Neal L, Katsamba PS, Ahlsen G, Balaji V, Hoppe T, Shapiro L, Oren-Suissa M, Hobert O. Ubiquitin-dependent regulation of a conserved DMRT protein controls sexually dimorphic synaptic connectivity and behavior. eLife 2020; 9:59614. [PMID: 33021200 PMCID: PMC7538159 DOI: 10.7554/elife.59614] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 09/05/2020] [Indexed: 12/20/2022] Open
Abstract
Sex-specific synaptic connectivity is beginning to emerge as a remarkable, but little explored feature of animal brains. We describe here a novel mechanism that promotes sexually dimorphic neuronal function and synaptic connectivity in the nervous system of the nematode Caenorhabditis elegans. We demonstrate that a phylogenetically conserved, but previously uncharacterized Doublesex/Mab-3 related transcription factor (DMRT), dmd-4, is expressed in two classes of sex-shared phasmid neurons specifically in hermaphrodites but not in males. We find dmd-4 to promote hermaphrodite-specific synaptic connectivity and neuronal function of phasmid sensory neurons. Sex-specificity of DMD-4 function is conferred by a novel mode of posttranslational regulation that involves sex-specific protein stabilization through ubiquitin binding to a phylogenetically conserved but previously unstudied protein domain, the DMA domain. A human DMRT homolog of DMD-4 is controlled in a similar manner, indicating that our findings may have implications for the control of sexual differentiation in other animals as well.
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Affiliation(s)
- Emily A Bayer
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, United States
| | - Rebecca C Stecky
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, United States
| | - Lauren Neal
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, United States
| | - Phinikoula S Katsamba
- Department of Biochemistry and Molecular Biophysics, Columbia University Irving Medical Center, New York, United States
| | - Goran Ahlsen
- Department of Biochemistry and Molecular Biophysics, Columbia University Irving Medical Center, New York, United States
| | - Vishnu Balaji
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Thorsten Hoppe
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Lawrence Shapiro
- Department of Biochemistry and Molecular Biophysics, Columbia University Irving Medical Center, New York, United States
| | - Meital Oren-Suissa
- Weizmann Institute of Science, Department of Neurobiology, Rehovot, Israel
| | - Oliver Hobert
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, United States.,Department of Biochemistry and Molecular Biophysics, Columbia University Irving Medical Center, New York, United States
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10
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Qiu Z, Sheesley P, Ahn JH, Yu EJ, Lee M. A Novel Mutation in an NPXY Motif of β Integrin Reveals Phenotypes Similar to him-4/hemicentin. Front Cell Dev Biol 2019; 7:247. [PMID: 31720287 PMCID: PMC6827421 DOI: 10.3389/fcell.2019.00247] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 10/08/2019] [Indexed: 11/13/2022] Open
Abstract
Integrin, an αβ heterodimeric cell surface receptor for the extracellular matrix (ECM), carries two tyrosine phosphorylation motifs in the cytoplasmic tail of the β subunit. NPXY (Asn-Pro-x-Tyr) is a conserved tyrosine phosphorylation motif that binds to the phospho-tyrosine binding (PTB) domain. We generated a tyrosine to glutamic acid (E) mutation to modify tyrosine (Y) into a negatively charged amino NPXY in the βpat-3 integrin of Caenorhabditis elegans. The transgenic rescue animal displayed defects in gonad migration and tail morphology. Also, the mutant animals produced a high number of males, suggesting that the Y to E mutation in βpat-3 integrin causes a phenotype similar to that of Him mutant. Further analyses revealed that males of pat-3(Y804E) and him-4/hemicentin share additional phenotypes such as abnormal gonad and unsuccessful mating. A pat-3 transgenic rescue mutant with a non-polar phenylalanine (F) in NPXY, pat-3(Y792/804F), suppressed the high male number, defective mating, inviable zygote, and the abnormal gonad of him-4 mutants, indicating that Y to F mutation in both NPXY motifs suppressed the him-4 phenotypes. This finding supports the idea that the ECM determines the activation state in integrin NPXY motifs; him-4/hemicentin may directly or indirectly interact with integrins and maintain the NPXY non-charged. Our findings provide new insight into a suppressive role of an ECM molecule in integrin NPXY phosphorylation.
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Affiliation(s)
| | | | | | | | - Myeongwoo Lee
- Department of Biology, Baylor University, Waco, TX, United States
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11
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Genomic Characterization of Diverse Gyroviruses Identified in the Feces of Domestic Cats. Sci Rep 2019; 9:13303. [PMID: 31527770 PMCID: PMC6746754 DOI: 10.1038/s41598-019-49955-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 09/03/2019] [Indexed: 12/22/2022] Open
Abstract
Gyroviruses (GyVs) are small, single-stranded, circular DNA viruses in the genus Gyrovirus, which consists of the chicken anemia virus (CAV) prototype and nine other viral species. These different GyV species have been reported in chickens, humans, mice, and companion animals. To date, CAV has been identified in the feces of domestic cats, while the circulation of other GyV species in cats is currently unknown. In the present study, 197 fecal samples were collected from pet cats in northeast China, and samples were screened for different GyV species by PCR. Twelve GyV strains were identified from the feces of pet cats. These included 4 positive for CAV, 3 for HGyV/AGV2, 3 for GyV3 and 2 positive for GyV6. The complete genome sequences of the 12 cat-sourced GyV strains showed 93.9-99.7% nucleotide identities to the homologous reference GyV strains. Phylogenetic analyses based on the complete genomes, VP1, VP2 and VP3 genes showed the identical classification of GyV species with previous reports. Moreover, one and four unique amino acid substitutions were identified in the VP1 protein of the cat-sourced HGyV/AGV2 and GyV6 strains, respectively, and one substitution was also observed in the VP2 protein of one GyV6 strain identified in this study. In conclusion, our investigation demonstrates that the diverse GyV species were circulating in domestic cats, and provides the first molecular evidence for the circulation of HGyV/AGV2, GyV3 and GyV6 in domestic cats. These cat-origin GyVs possessed considerable genetic diversity. This study also raises the possibility that domestic cats, as reservoirs for gyroviruses, may inadvertently disseminate viruses to other species, e.g., humans and chickens.
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12
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Rice GR, Barmina O, Luecke D, Hu K, Arbeitman M, Kopp A. Modular tissue-specific regulation of doublesex underpins sexually dimorphic development in Drosophila. Development 2019; 146:dev178285. [PMID: 31285355 PMCID: PMC6679366 DOI: 10.1242/dev.178285] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 06/28/2019] [Indexed: 11/20/2022]
Abstract
The ability of a single genome to produce distinct and often dramatically different male and female forms is one of the wonders of animal development. In Drosophila melanogaster, most sexually dimorphic traits are controlled by sex-specific isoforms of the doublesex (dsx) transcription factor, and dsx expression is mostly limited to cells that give rise to sexually dimorphic traits. However, it is unknown how this mosaic of sexually dimorphic and monomorphic organs arises. Here, we characterize the cis-regulatory sequences that control dsx expression in the foreleg, which contains multiple types of sex-specific sensory organs. We find that separate modular enhancers are responsible for dsx expression in each sexually dimorphic organ. Expression of dsx in the sex comb is co-regulated by two enhancers with distinct spatial and temporal specificities that are separated by a genitalia-specific enhancer. The sex comb-specific enhancer from D. willistoni, a species that primitively lacks sex combs, is not active in the foreleg. Thus, the mosaic of sexually dimorphic and monomorphic organs depends on modular regulation of dsx transcription by dedicated cell type-specific enhancers.
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Affiliation(s)
- Gavin R Rice
- Department of Evolution and Ecology, University of California-Davis, Davis, CA 95616, USA
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Olga Barmina
- Department of Evolution and Ecology, University of California-Davis, Davis, CA 95616, USA
| | - David Luecke
- Department of Evolution and Ecology, University of California-Davis, Davis, CA 95616, USA
| | - Kevin Hu
- Department of Evolution and Ecology, University of California-Davis, Davis, CA 95616, USA
| | - Michelle Arbeitman
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL 32306, USA
| | - Artyom Kopp
- Department of Evolution and Ecology, University of California-Davis, Davis, CA 95616, USA
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13
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Abstract
Several species of Caenorhabditis nematodes, including Caenorhabditis elegans, have recently evolved self-fertile hermaphrodites from female/male ancestors. These hermaphrodites can either self-fertilize or mate with males, and the extent of outcrossing determines subsequent male frequency. Using experimental evolution, the authors show that a gene family with a historical role in sperm competition plays a large role in regulating male frequency after self-fertility evolves. By reducing, but not completely eliminating outcrossing, loss of the mss genes contributes to adaptive tuning of the sex ratio in a newly self-fertile species. The maintenance of males at intermediate frequencies is an important evolutionary problem. Several species of Caenorhabditis nematodes have evolved a mating system in which selfing hermaphrodites and males coexist. While selfing produces XX hermaphrodites, cross-fertilization produces 50% XO male progeny. Thus, male mating success dictates the sex ratio. Here, we focus on the contribution of the male secreted short (mss) gene family to male mating success, sex ratio, and population growth. The mss family is essential for sperm competitiveness in gonochoristic species, but has been lost in parallel in androdioecious species. Using a transgene to restore mss function to the androdioecious Caenorhabditis briggsae, we examined how mating system and population subdivision influence the fitness of the mss+ genotype. Consistent with theoretical expectations, when mss+ and mss-null (i.e., wild type) genotypes compete, mss+ is positively selected in both mixed-mating and strictly outcrossing situations, though more strongly in the latter. Thus, while sexual mode alone affects the fitness of mss+, it is insufficient to explain its parallel loss. However, in genetically homogenous androdioecious populations, mss+ both increases male frequency and depresses population growth. We propose that the lack of inbreeding depression and the strong subdivision that characterize natural Caenorhabditis populations impose selection on sex ratio that makes loss of mss adaptive after self-fertility evolves.
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14
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Hou L, Li B, Ding D, Kang L, Wang X. CREB-B acts as a key mediator of NPF/NO pathway involved in phase-related locomotor plasticity in locusts. PLoS Genet 2019; 15:e1008176. [PMID: 31150381 PMCID: PMC6561586 DOI: 10.1371/journal.pgen.1008176] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 06/12/2019] [Accepted: 05/07/2019] [Indexed: 12/14/2022] Open
Abstract
Gene expression changes in neural systems are essential for environment-induced behavioral plasticity in animals; however, neuronal signaling pathways mediating the effect of external stimuli on transcriptional changes are largely unknown. Recently, we have demonstrated that the neuropeptide F (NPF)/nitric oxide (NO) signaling pathway plays a regulatory role in phase-related locomotor plasticity in the migratory locust, Locusta migratoria. Here, we report that a conserved transcription factor, cAMP response element-binding protein B (CREB-B), is a key mediator involved in the signaling pathway from NPF2 to NOS in the migratory locust, triggering locomotor activity shift between solitarious and gregarious phases. We find that CREB-B directly activates brain NOS expression by interacting with NOS promoter region. The phosphorylation at serine 110 site of CREB-B dynamically changes in response to population density variation and is negatively controlled by NPF2. The involvement of CREB-B in NPF2-regulated locomotor plasticity is further validated by RNAi experiment and behavioral assay. Furthermore, we reveal that protein kinase A mediates the regulatory effects of NPF2 on CREB-B phosphorylation and NOS transcription. These findings highlight a precise signal cascade underlying environment-induced behavioral plasticity.
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Affiliation(s)
- Li Hou
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Beibei Li
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Ding Ding
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Le Kang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- Beijing Institutes of Life Science, Chinese Academy of Sciences, Beijing, China
| | - Xianhui Wang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
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15
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Li L, Mao A, Wang P, Ning G, Cao Y, Wang Q. Endodermal pouch-expressed dmrt2b is important for pharyngeal cartilage formation. Biol Open 2018; 7:bio.035444. [PMID: 30341107 PMCID: PMC6310889 DOI: 10.1242/bio.035444] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Pharyngeal pouches, a series of outpocketings derived from the foregut endoderm, are essential for craniofacial skeleton formation. However, the molecular mechanisms underlying endodermal pouch-regulated head cartilage development are not fully understood. In this study, we find that zebrafish dmrt2b, a gene encoding Doublesex- and Mab-3-related transcription factor, is specifically expressed in endodermal pouches and required for normal pharyngeal cartilage development. Loss of dmrt2b doesn't affect cranial neural crest (CNC) specification and migration, but leads to prechondrogenic condensation defects by reducing cxcl12b expression after CNC cell movement into the pharyngeal arches. Moreover, dmrt2b inactivation results in reduced proliferation and impaired differentiation of CNC cells. We also show that dmrt2b suppresses crossveinless 2 expression in endodermal pouches to maintain BMP/Smad signaling in the arches, thereby facilitating CNC cell proliferation and chondrogenic differentiation. This work provides insight into how transcription factors expressed in endodermal pouches regulate pharyngeal skeleton development through tissue-tissue interactions.
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Affiliation(s)
- Linwei Li
- State Key Laboratory of Membrane Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Zoology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100101, China
| | - Aihua Mao
- State Key Laboratory of Membrane Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Zoology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100101, China
| | - Peng Wang
- State Key Laboratory of Membrane Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Zoology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100101, China
| | - Guozhu Ning
- State Key Laboratory of Membrane Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Zoology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100101, China
| | - Yu Cao
- State Key Laboratory of Membrane Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Zoology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100101, China
| | - Qiang Wang
- State Key Laboratory of Membrane Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Zoology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100101, China .,Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing 100101, China
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16
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Haag ES, Fitch DHA, Delattre M. From "the Worm" to "the Worms" and Back Again: The Evolutionary Developmental Biology of Nematodes. Genetics 2018; 210:397-433. [PMID: 30287515 PMCID: PMC6216592 DOI: 10.1534/genetics.118.300243] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 08/03/2018] [Indexed: 12/13/2022] Open
Abstract
Since the earliest days of research on nematodes, scientists have noted the developmental and morphological variation that exists within and between species. As various cellular and developmental processes were revealed through intense focus on Caenorhabditis elegans, these comparative studies have expanded. Within the genus Caenorhabditis, they include characterization of intraspecific polymorphisms and comparisons of distinct species, all generally amenable to the same laboratory culture methods and supported by robust genomic and experimental tools. The C. elegans paradigm has also motivated studies with more distantly related nematodes and animals. Combined with improved phylogenies, this work has led to important insights about the evolution of nematode development. First, while many aspects of C. elegans development are representative of Caenorhabditis, and of terrestrial nematodes more generally, others vary in ways both obvious and cryptic. Second, the system has revealed several clear examples of developmental flexibility in achieving a particular trait. This includes developmental system drift, in which the developmental control of homologous traits has diverged in different lineages, and cases of convergent evolution. Overall, the wealth of information and experimental techniques developed in C. elegans is being leveraged to make nematodes a powerful system for evolutionary cellular and developmental biology.
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Affiliation(s)
- Eric S Haag
- Department of Biology, University of Maryland, College Park, Maryland 20742
| | | | - Marie Delattre
- Laboratoire de Biologie Moléculaire de la Cellule, CNRS, INSERM, Ecole Normale Supérieure de Lyon, 69007, France
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17
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Abstract
Sex differences in the brain are prominent features across the animal kingdom. Understanding the anatomical and regulatory mechanisms behind these differences is critical for both explaining sexually dimorphic behaviors and developing sex-targeted treatments for neurological disorders. Clinical studies considering sex biases and basic research on animal models have provided much evidence for the existence of sex differences in the brain and, in a larger sense, sexual dimorphisms in the nervous system. However, due to the complexity of structure and dimorphic behaviors, it is yet unclear precisely how neuronal sexual dimorphisms are regulated on a molecular or cellular level. This commentary reviews available tools for investigating sexual dimorphisms using a simple model organism, the roundworm Caenorhabditis elegans ( C. elegans), which enables one to study gene regulation at single-cell resolution with a number of cutting-edge molecular and genetic technologies. I highlight the doublesex/mab-3 family of transcription factors, first discovered in invertebrates, and their roles in a potentially universal regulatory mechanism underlying neuronal sexual dimorphisms. Studies of these transcription factors using C. elegans, fruit flies, and vertebrates will promote our understanding of fundamental mechanisms behind sex differences in the brain.
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Affiliation(s)
- Chen Wang
- Department of Biological Sciences, Columbia University, New York, NY, USA
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18
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Fagan KA, Luo J, Lagoy RC, Schroeder FC, Albrecht DR, Portman DS. A Single-Neuron Chemosensory Switch Determines the Valence of a Sexually Dimorphic Sensory Behavior. Curr Biol 2018; 28:902-914.e5. [PMID: 29526590 PMCID: PMC5862148 DOI: 10.1016/j.cub.2018.02.029] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 02/11/2018] [Accepted: 02/14/2018] [Indexed: 01/08/2023]
Abstract
Biological sex, a fundamental dimension of internal state, can modulate neural circuits to generate behavioral variation. Understanding how and why circuits are tuned by sex can provide important insights into neural and behavioral plasticity. Here we find that sexually dimorphic behavioral responses to C. elegans ascaroside sex pheromones are implemented by the functional modulation of shared chemosensory circuitry. In particular, the sexual state of a single sensory neuron pair, ADF, determines the nature of an animal's behavioral response regardless of the sex of the rest of the body. Genetic feminization of ADF causes males to be repelled by, rather than attracted to, ascarosides, whereas masculinization of ADF has the opposite effect in hermaphrodites. When ADF is ablated, both sexes are weakly repelled by ascarosides. Genetic sex modulates ADF function by tuning chemosensation: although ADF is functional in both sexes, it detects the ascaroside ascr#3 only in males, a consequence of cell-autonomous action of the master sexual regulator tra-1. This occurs in part through the conserved DM-domain gene mab-3, which promotes the male state of ADF. The sexual modulation of ADF has a key role in reproductive fitness, as feminization or ablation of ADF renders males unable to use ascarosides to locate mates. Our results reveal an economical mechanism in which sex-specific behavioral valence arises through the cell-autonomous regulation of a chemosensory switch by genetic sex, allowing a social cue with salience for both sexes to elicit navigational responses commensurate with the differing needs of each.
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Affiliation(s)
- Kelli A Fagan
- Neuroscience Graduate Program, University of Rochester, 601 Elmwood Avenue, Rochester, NY 14610, USA
| | - Jintao Luo
- Del Monte Institute for Neuroscience, University of Rochester, 601 Elmwood Avenue, Rochester, NY 14610, USA; Center for Neurotherapeutics Development, University of Rochester, 601 Elmwood Avenue, Rochester, NY 14610, USA
| | - Ross C Lagoy
- Department of Biomedical Engineering, Worcester Polytechnic Institute, 60 Prescott Street, Room 4004, Worcester, MA 01605, USA
| | | | - Dirk R Albrecht
- Department of Biomedical Engineering, Worcester Polytechnic Institute, 60 Prescott Street, Room 4004, Worcester, MA 01605, USA
| | - Douglas S Portman
- Del Monte Institute for Neuroscience, University of Rochester, 601 Elmwood Avenue, Rochester, NY 14610, USA; Center for Neurotherapeutics Development, University of Rochester, 601 Elmwood Avenue, Rochester, NY 14610, USA; Departments of Biomedical Genetics, Neuroscience, and Biology, University of Rochester, 601 Elmwood Avenue, Box 645, Rochester, NY 14610, USA.
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19
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Kim B, Suo B, Emmons SW. Gene Function Prediction Based on Developmental Transcriptomes of the Two Sexes in C. elegans. Cell Rep 2017; 17:917-928. [PMID: 27732864 PMCID: PMC5656000 DOI: 10.1016/j.celrep.2016.09.051] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 08/03/2016] [Accepted: 09/16/2016] [Indexed: 11/29/2022] Open
Abstract
We compare whole-animal RNA-seq transcriptomes for C. elegans males and hermaphrodites from the late L3 larval stage to young adulthood. During this interval, male sexual structures develop, including extensive neurogenesis and synaptogenesis that nearly doubles the size of the nervous system. Previous genome-wide expression studies in C. elegans have usually focused on only one sex—the hermaphrodite—and there are a relatively large number of genes that remain without meaningful annotation. In the present study, differential expression analysis of the RNA-seq data revealed 1,751 genes expressed at a higher level in the male. By differential expression and co-expression analyses, we identified transcription factors required for differentiation of male genital structures, semen proteins, and candidates for components of synapse function. Comparison with other prediction tools suggests that our dataset can expand gene predictions. The results validate the dataset as a rich resource for future gene discovery in C. elegans.
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Affiliation(s)
- Byunghyuk Kim
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Bangxia Suo
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Scott W Emmons
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY 10461, USA; Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
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20
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Portman DS. Sexual modulation of sex-shared neurons and circuits in Caenorhabditis elegans. J Neurosci Res 2017; 95:527-538. [PMID: 27870393 DOI: 10.1002/jnr.23912] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 08/10/2016] [Accepted: 08/10/2016] [Indexed: 12/16/2022]
Abstract
Studies using the nematode C. elegans have provided unique insights into the development and function of sex differences in the nervous system. Enabled by the relative simplicity of this species, comprehensive studies have solved the complete cellular neuroanatomy of both sexes as well as the complete neural connectomes of the entire adult hermaphrodite and the adult male tail. This work, together with detailed behavioral studies, has revealed three aspects of sex differences in the nervous system: sex-specific neurons and circuits; circuits with sexually dimorphic synaptic connectivity; and sex differences in the physiology and functions of shared neurons and circuits. At all of these levels, biological sex influences neural development and function through the activity of a well-defined genetic hierarchy that acts throughout the body to translate chromosomal sex into the state of a master autosomal regulator of sexual differentiation, the transcription factor TRA-1A. This Review focuses on the role of genetic sex in implementing sex differences in shared neurons and circuits, with an emphasis on linking the sexual modulation of specific neural properties to the specification and optimization of sexually divergent and dimorphic behaviors. An important and unexpected finding from these studies is that chemosensory neurons are a primary focus of sexual modulation, with genetic sex adaptively shaping chemosensory repertoire to guide behavioral choice. Importantly, hormone-independent functions of genetic sex are the principal drivers of all of these sex differences, making nematodes an excellent model for understanding similar but poorly understood mechanisms that likely act throughout the animal kingdom. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Douglas S Portman
- Center for Neural Development and Disease, Department of Biomedical Genetics, Neuroscience, and Biology, University of Rochester Medical Center, Rochester, New York
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21
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Duan M, Xiong J, Lu D, Wang G, Ai H. Transcriptome Sequencing Analysis and Functional Identification of Sex Differentiation Genes from the Mosquito Parasitic Nematode, Romanomermis wuchangensis. PLoS One 2016; 11:e0163127. [PMID: 27662191 PMCID: PMC5035087 DOI: 10.1371/journal.pone.0163127] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 09/03/2016] [Indexed: 11/25/2022] Open
Abstract
Mosquito-transmitted diseases like malaria and dengue fever are global problem and an estimated 50–100 million of dengue or dengue hemorrhagic fever cases are reported worldwide every year. The mermithid nematode Romanomermis wuchangensis has been successfully used as an ecosystem-friendly biocontrol agent for mosquito prevention in laboratory studies. However, this nematode can not undergo sex differentiation in vitro culture, which has seriously affected their application of biocontrol in the field. In this study, based on transcriptome sequencing analysis of R. wuchangensis, Rwucmab-3, Rwuclaf-1 and Rwuctra-2 were cloned and used to investigate molecular regulatory function of sex differentiation. qRT-PCR results demonstrated that the expression level of Rwucmab-3 between male and female displayed obvious difference on the 3rd day of parasitic stage, which was earlier than Rwuclaf-1 and Rwuctra-2, highlighting sex differentiation process may start on the 3rd day of parasitic stage. Besides, FITC was used as a marker to test dsRNA uptake efficiency of R. wuchangensis, which fluorescence intensity increased with FITC concentration after 16 h incubation, indicating this nematode can successfully ingest soaking solution via its cuticle. RNAi results revealed the sex ratio of R. wuchangensis from RNAi treated groups soaked in dsRNA of Rwucmab-3 was significantly higher than gfp dsRNA treated groups and control groups, highlighting RNAi of Rwumab-3 may hinder the development of male nematodes. These results suggest that Rwucmab-3 mainly involves in the initiation of sex differentiation and the development of male sexual dimorphism. Rwuclaf-1 and Rwuctra-2 may play vital role in nematode reproductive and developmental system. In conclusion, transcript sequences presented in this study could provide more bioinformatics resources for future studies on gene cloning and other molecular regulatory mechanism in R. wuchangensis. Moreover, identification and functional analysis of sex differentiation genes may clarify the sex differentiation mechanism of R. wuchangensis, which are helpful to solve the uncompleted sex differentiation problem in vitro culture and the potential large-scale field application controlling the larvae of C. quinquefasciatus, A. aegypti and A. albopictus.
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Affiliation(s)
- Mingyue Duan
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, China
| | - Jinfeng Xiong
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, China
| | - Dandan Lu
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, China
| | - Guoxiu Wang
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, China
- * E-mail: (HA); (GW)
| | - Hui Ai
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, China
- * E-mail: (HA); (GW)
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22
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García LR, Portman DS. Neural circuits for sexually dimorphic and sexually divergent behaviors in Caenorhabditis elegans. Curr Opin Neurobiol 2016; 38:46-52. [PMID: 26929998 DOI: 10.1016/j.conb.2016.02.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 02/09/2016] [Indexed: 01/07/2023]
Abstract
Increasing interest in sex differences in Caenorhabditis elegans neurobiology is resulting from several advances, including the completion of the male tail connectome and the surprising discovery of two 'new' neurons in the male head. In this species, sex-specific circuits in the hermaphrodite and male control reproductive behaviors such as egg-laying and copulation, respectively. Studies of these systems are revealing interesting similarities and contrasts, particularly in the mechanisms by which nutritional status influences reproductive behaviors. Other studies have highlighted the importance of sexual modulation of shared neurons and circuits in optimizing behavioral strategies. Together, these findings indicate that C. elegans uses intertwined, distributed sex differences in circuit structure and function to implement sex-specific as well as sexually divergent, shared behaviors.
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Affiliation(s)
- L René García
- Department of Biology, Howard Hughes Medical Institute, Texas A&M University, 3258 TAMU, College Station, TX 77843-3258, United States
| | - Douglas S Portman
- Department of Biomedical Genetics and Center for Neural Development and Disease, University of Rochester, 601 Elmwood Ave., Box 645, Rochester, NY 14642, United States.
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23
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Su L, Zhou F, Ding Z, Gao Z, Wen J, Wei W, Wang Q, Wang W, Liu H. Transcriptional variants of Dmrt1 and expression of four Dmrt genes in the blunt snout bream, Megalobrama amblycephala. Gene 2015; 573:205-15. [DOI: 10.1016/j.gene.2015.07.044] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 06/20/2015] [Accepted: 07/13/2015] [Indexed: 10/23/2022]
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24
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The roles of Dmrt (Double sex/Male-abnormal-3 Related Transcription factor) genes in sex determination and differentiation mechanisms: Ubiquity and diversity across the animal kingdom. C R Biol 2015; 338:451-62. [DOI: 10.1016/j.crvi.2015.04.010] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Revised: 04/14/2015] [Accepted: 04/15/2015] [Indexed: 02/06/2023]
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25
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Emmons SW. The development of sexual dimorphism: studies of the Caenorhabditis elegans male. WILEY INTERDISCIPLINARY REVIEWS. DEVELOPMENTAL BIOLOGY 2014; 3:239-62. [PMID: 25262817 PMCID: PMC4181595 DOI: 10.1002/wdev.136] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Accepted: 04/02/2014] [Indexed: 01/09/2023]
Abstract
Studies of the development of the Caenorhabditis elegans male have been carried out with the aim of understanding the basis of sexual dimorphism. Postembryonic development of the two C. elegans sexes differs extensively. Development along either the hermaphrodite or male pathway is specified initially by the X to autosome ratio. The regulatory events initiated by this ratio include a male-determining paracrine intercellular signal. Expression of this signal leads to different consequences in three regions of the body: the nongonadal soma, the somatic parts of the gonad, and the germ line. In the nongonadal soma, activity of the key Zn-finger transcription factor TRA-1 determines hermaphrodite development; in its absence, the male pathway is followed. Only a few genes directly regulated by TRA-1 are currently known, including members of the evolutionarily conserved, male-determining DM domain Zn-finger transcription factors. In the somatic parts of the gonad and germ line, absence of TRA-1 activity is not sufficient for full expression of the male pathway. Several additional transcription factors involved have been identified. In the germ line, regulatory genes for sperm development that act at the level of RNA in the cytoplasm play a prominent role.
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Affiliation(s)
- Scott W. Emmons
- Albert Einstein College of Medicine 1300 Morris Park Ave. Bronx, New York 10461
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26
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Identification of Dmrt genes and their up-regulation during gonad transformation in the swamp eel (Monopterus albus). Mol Biol Rep 2014; 41:1237-45. [PMID: 24390316 DOI: 10.1007/s11033-013-2968-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Accepted: 12/23/2013] [Indexed: 10/25/2022]
Abstract
The swamp eel is a teleost fish with a characteristic of natural sex reversal and an ideal model for vertebrate sexual development. However, underlying molecular mechanisms are poorly understood. We report the identification of five DM (doublesex and mab-3) domain genes in the swamp eel that include Dmrt2, Dmrt2b, Dmrt3, Dmrt4 and Dmrt5, which encode putative proteins of 527, 373, 471, 420 and 448 amino acids, respectively. Phylogenetic tree showed that these genes are clustered into corresponding branches of the DM genes in vertebrates. Southern blot analysis indicated that the Dmrt1-Dmrt3-Dmrt2 genes are tightly linked in a conserved gene cluster. Notably, these Dmrt genes are up-regulated during gonad transformation. Furthermore, mRNA in situ hybridisation showed that Dmrt2, Dmrt3, Dmrt4 and Dmrt5 are expressed in developing germ cells. These results are evidence that the DM genes are involved in sexual differentiation in the swamp eel.
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27
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Bellefroid EJ, Leclère L, Saulnier A, Keruzore M, Sirakov M, Vervoort M, De Clercq S. Expanding roles for the evolutionarily conserved Dmrt sex transcriptional regulators during embryogenesis. Cell Mol Life Sci 2013; 70:3829-45. [PMID: 23463235 PMCID: PMC11113232 DOI: 10.1007/s00018-013-1288-2] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Revised: 01/18/2013] [Accepted: 01/31/2013] [Indexed: 01/20/2023]
Abstract
Dmrt genes encode a large family of transcription factors characterized by the presence of a DM domain, an unusual zinc finger DNA binding domain. While Dmrt genes are well known for their important role in sexual development in arthropodes, nematodes and vertebrates, several new findings indicate emerging functions of this gene family in other developmental processes. Here, we provide an overview of the evolution, structure and mechanisms of action of Dmrt genes. We summarize recent findings on their function in sexual regulation and discuss more extensively the role played by these proteins in somitogenesis and neural development.
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Affiliation(s)
- Eric J Bellefroid
- Laboratoire de Génétique du Développement, Institut de Biologie et de Médecine Moléculaires (IBMM), Université Libre de Bruxelles, rue des Profs. Jeener et Brachet 12, 6041, Gosselies, Belgium,
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28
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TRA-1 ChIP-seq reveals regulators of sexual differentiation and multilevel feedback in nematode sex determination. Proc Natl Acad Sci U S A 2013; 110:16033-8. [PMID: 24046365 DOI: 10.1073/pnas.1312087110] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
How sexual regulators translate global sexual fate into appropriate local sexual differentiation events is perhaps the least understood aspect of sexual development. Here we have used ChIP followed by deep sequencing (ChIP-seq) to identify direct targets of the nematode global sexual regulator Transformer 1 (TRA-1), a transcription factor acting at the interface between organism-wide and cell-specific sexual regulation to control all sex-specific somatic differentiation events. We identified 184 TRA-1-binding sites in Caenorhabditis elegans, many with temporal- and/or tissue-specific TRA-1 association. We also identified 78 TRA-1-binding sites in the related nematode Caenorhabditis briggsae, 19 of which are conserved between the two species. Some DNA segments containing TRA-1-binding sites drive male-specific expression patterns, and RNAi depletion of some genes adjacent to TRA-1-binding sites results in defects in male sexual development. TRA-1 binds to sites adjacent to a number of heterochronic regulatory genes, some of which drive male-specific expression, suggesting that TRA-1 imposes sex specificity on developmental timing. We also found evidence for TRA-1 feedback regulation of the global sex-determination pathway: TRA-1 binds its own locus and those of multiple upstream masculinizing genes, and most of these associations are conserved in C. briggsae. Thus, TRA-1 coordinates sexual development by reinforcing the sex-determination decision and directing downstream sexual differentiation events.
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29
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Abstract
Transforming Growth Factor-β (TGF-β) superfamily ligands regulate many aspects of cell identity, function, and survival in multicellular animals. Genes encoding five TGF-β family members are present in the genome of C. elegans. Two of the ligands, DBL-1 and DAF-7, signal through a canonical receptor-Smad signaling pathway; while a third ligand, UNC-129, interacts with a noncanonical signaling pathway. No function has yet been associated with the remaining two ligands. Here we summarize these signaling pathways and their biological functions.
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Affiliation(s)
- Tina L Gumienny
- Department of Molecular and Cellular Medicine, Texas A&M Health Science Center College of Medicine, College Station, TX 77843, USA
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30
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Agbor VA, Tao S, Lei N, Heckert LL. A Wt1-Dmrt1 transgene restores DMRT1 to sertoli cells of Dmrt1(-/-) testes: a novel model of DMRT1-deficient germ cells. Biol Reprod 2013; 88:51. [PMID: 23255335 DOI: 10.1095/biolreprod.112.103135] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
DMRT1 is an evolutionarily conserved transcriptional factor expressed only in the postnatal testis, where it is produced in Sertoli cells and germ cells. While deletion of Dmrt1 in mice demonstrated it is required for postnatal testis development and fertility, much is still unknown about its temporal- and cell-specific functions. This study characterized a novel mouse model of DMRT1-deficient germ cells that was generated by breeding Dmrt1-null (Dmrt1(-/-)) mice with Wt1-Dmrt1 transgenic (Dmrt1(+/-;tg)) mice, which express a rat Dmrt1 cDNA in gonadal supporting cells by directing it from the Wilms tumor 1 locus in a yeast artificial chromosome transgene. Like Dmrt1(-/-) mice, male Dmrt1(-/-) transgenic mice (Dmrt1(-/-;tg)) were infertile, while female mice were fertile. Immunohistochemistry and Western blot analysis showed transgenic DMRT1 expressed in supporting cells of the newborn gonads of both sex and in Sertoli cells of the testis afterbirth. Sertoli cells were evaluated by electron microscopy, revealing that maturation of Dmrt1(-/-;tg) Sertoli cells was incomplete. Morphological analysis of testes from 42-day-old mice showed that, compared to Dmrt1(-/-) mice, Dmrt1(-/-;tg) mice have improved seminiferous tubule structure, with lumens present in many. Immunohistochemistry of the polarity markers ESPIN and NECTIN-2 showed that DMRT1 in Sertoli cells is required for NECTIN-2 expression and influences organization of ectoplasmic specializations. Further functional analyses of the transgene on a Dmrt1(-/-) background showed that it did not rescue the decrease in Dmrt1(-/-) testis size, but when expressed on a wild-type background, exogenous DMRT1 prevented the normal age-related decline in testis size and enhanced sperm progressive motility. The studies suggest that DMRT1 in Sertoli cells regulates tubule morphology, spermatogenesis, and sperm function via its effects on Sertoli cell maturation and polarity. Furthermore, expression and function of transgenic DMRT1 in Sertoli cells establishes a novel mouse model of DMRT1-deficient germ cells generated by breeding Dmrt1-null mice with Wt1-Dmrt1 transgenic mice (rescue; Dmrt1(-/-;tg)).
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Affiliation(s)
- Valentine A Agbor
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS 66160, USA
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31
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Miersch C, Döring F. Sex differences in carbohydrate metabolism are linked to gene expression in Caenorhabditis elegans. PLoS One 2012; 7:e44748. [PMID: 22984551 PMCID: PMC3439400 DOI: 10.1371/journal.pone.0044748] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Accepted: 08/06/2012] [Indexed: 11/18/2022] Open
Abstract
The male and the hermaphrodite forms of the nematode Caenorhabditis elegans (C. elegans) differ markedly in anatomy, nervous system and behavior at adulthood. Using the male mutants fog-2, him-5, and him-8, we compared body proportions and composition, and aspects of carbohydrate metabolism and gene expression between the C. elegans sexes in three adult stages. In all experiments, both sexes were grown on the same plate and separated using flow cytometry. The fat to fat-free mass ratio and the body volume-adjusted fat mass is similar between the sexes, although the body size is more than 50% smaller in adult males than in age-matched hermaphrodites. The volume-adjusted total RNA content is approximately 2-fold lower in males. Biochemical and NMR-based analyses reveal higher trehalose levels and much lower glucose levels in males than in hermaphrodites. The resulting trehalose-to-glucose ratio is 5.4-fold higher in males. These sex differences are reflected in gene expression data because the genes encoding key enzymes of the glycolysis and trehalose synthesis pathways are more highly expressed in males than in hermaphrodites. Notably, expression of the phosphofructokinase gene (C50F4.2) is 29-fold higher in males. Comparative analysis of gene expression data identifies 285 male-specific and 160 hermaphrodite-specific genes. These include transcription factor and C-type lectin-encoding genes. More than 35% of all C-type lectin genes are more highly expressed in males. The expression of many C-type lectin genes differs by a factor of >100 between the sexes. In conclusion, we found sex differences in carbohydrate metabolism that are linked to gene expression and identified certain lectin genes that are differentially expressed by the C. elegans sexes.
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Affiliation(s)
- Claudia Miersch
- Department of Molecular Prevention, Institute of Human Nutrition and Food Science, Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Frank Döring
- Department of Molecular Prevention, Institute of Human Nutrition and Food Science, Christian-Albrechts-University of Kiel, Kiel, Germany
- * E-mail:
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32
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Liu P, He K, Li Y, Wu Q, Yang P, Wang D. Exposure to mercury causes formation of male-specific structural deficits by inducing oxidative damage in nematodes. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2012; 79:90-100. [PMID: 22209111 DOI: 10.1016/j.ecoenv.2011.12.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2010] [Revised: 12/09/2011] [Accepted: 12/10/2011] [Indexed: 05/31/2023]
Abstract
Metal exposure causes reproductive damage in hermaphrodite nematodes, but effects of metals on male development are unclear. We here investigated the effects of mercury chloride exposure on development of males. Hg exposure severely increased the percentage of abnormal males, disrupted the development of male-specific structures, and caused high reactive oxygen species (ROS) production in male tails. Pre-treatment with antioxidant (vitamin E) protected the nematodes against toxicity from Hg exposure on development of male-specific structures. The ROS production in tails was closely correlated with formation of abnormal male-specific structures in males induced by Hg exposure. Moreover, mutations of clk-1, encoding ortholog of COQ7/CAT5, and daf-2, encoding an insulin/IGF receptor, functioned in two different pathways to suppress the formation of deficits in development of male-specific structures. Thus, three different lines of evidence support our conclusion that HgCl(2) causes male structure-specific teratogenesis via production of oxidative stress.
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Affiliation(s)
- Peidang Liu
- Key Laboratory of Environmental Medicine Engineering in Ministry of Education, Medical School of Southeast University, Nanjing 210009, China; Department of Biochemistry and Molecular Biology, Medical School of Southeast University, Nanjing 210009, China; Institute of Neuroscience, Medical School of Southeast University, Nanjing 210009, China
| | - Kewen He
- Key Laboratory of Environmental Medicine Engineering in Ministry of Education, Medical School of Southeast University, Nanjing 210009, China; Department of Biochemistry and Molecular Biology, Medical School of Southeast University, Nanjing 210009, China
| | - Yinxia Li
- Key Laboratory of Environmental Medicine Engineering in Ministry of Education, Medical School of Southeast University, Nanjing 210009, China; Department of Biochemistry and Molecular Biology, Medical School of Southeast University, Nanjing 210009, China
| | - Qiuli Wu
- Key Laboratory of Environmental Medicine Engineering in Ministry of Education, Medical School of Southeast University, Nanjing 210009, China; Department of Biochemistry and Molecular Biology, Medical School of Southeast University, Nanjing 210009, China
| | - Peng Yang
- Key Laboratory of Environmental Medicine Engineering in Ministry of Education, Medical School of Southeast University, Nanjing 210009, China; Department of Biochemistry and Molecular Biology, Medical School of Southeast University, Nanjing 210009, China
| | - Dayong Wang
- Key Laboratory of Environmental Medicine Engineering in Ministry of Education, Medical School of Southeast University, Nanjing 210009, China; Department of Biochemistry and Molecular Biology, Medical School of Southeast University, Nanjing 210009, China.
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Thomas CG, Woodruff GC, Haag ES. Causes and consequences of the evolution of reproductive mode in Caenorhabditis nematodes. Trends Genet 2012; 28:213-20. [PMID: 22480920 DOI: 10.1016/j.tig.2012.02.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Revised: 02/24/2012] [Accepted: 02/27/2012] [Indexed: 12/12/2022]
Abstract
Reproduction is directly connected to the suite of developmental and physiological mechanisms that enable it, but how it occurs also has consequences for the genetics, ecology and longer term evolutionary potential of a lineage. In the nematode Caenorhabditis elegans, anatomically female XX worms can self-fertilize their eggs. This ability evolved recently and in multiple Caenorhabditis lineages from male-female ancestors, providing a model for examining both the developmental causes and longer term consequences of a novel, convergently evolved reproductive mode. Here, we review recent work that implicates translation control in the evolution of XX spermatogenesis, with different selfing lineages possessing both reproducible and idiosyncratic features. We also discuss the consequences of selfing, which leads to a rapid loss of variation and relaxation of natural and sexual selection on mating-related traits, and may ultimately put selfing lineages at a higher risk of extinction.
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Affiliation(s)
- Cristel G Thomas
- Department of Biology, University of Maryland, College Park, MD 20742, USA
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34
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Mowrey WR, Portman DS. Sex differences in behavioral decision-making and the modulation of shared neural circuits. Biol Sex Differ 2012; 3:8. [PMID: 22436578 PMCID: PMC3352037 DOI: 10.1186/2042-6410-3-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2011] [Accepted: 03/21/2012] [Indexed: 11/10/2022] Open
Abstract
Animals prioritize behaviors according to their physiological needs and reproductive goals, selecting a single behavioral strategy from a repertoire of possible responses to any given stimulus. Biological sex influences this decision-making process in significant ways, differentiating the responses animals choose when faced with stimuli ranging from food to conspecifics. We review here recent work in invertebrate models, including C. elegans, Drosophila, and a variety of insects, mollusks and crustaceans, that has begun to offer intriguing insights into the neural mechanisms underlying the sexual modulation of behavioral decision-making. These findings show that an animal's sex can modulate neural function in surprisingly diverse ways, much like internal physiological variables such as hunger or thirst. In the context of homeostatic behaviors such as feeding, an animal's sex and nutritional status may converge on a common physiological mechanism, the functional modulation of shared sensory circuitry, to influence decision-making. Similarly, considerable evidence suggests that decisions on whether to mate or fight with conspecifics are also mediated through sex-specific neuromodulatory control of nominally shared neural circuits. This work offers a new perspective on how sex differences in behavior emerge, in which the regulated function of shared neural circuitry plays a crucial role. Emerging evidence from vertebrates indicates that this paradigm is likely to extend to more complex nervous systems as well. As men and women differ in their susceptibility to a variety of neuropsychiatric disorders affecting shared behaviors, these findings may ultimately have important implications for human health.
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Affiliation(s)
- William R Mowrey
- Center for Neural Development and Disease, School of Medicine and Dentistry, University of Rochester, 601 Elmwood Avenue, Box 645, Rochester, NY 14642, USA.
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Kopp A. Dmrt genes in the development and evolution of sexual dimorphism. Trends Genet 2012; 28:175-84. [PMID: 22425532 DOI: 10.1016/j.tig.2012.02.002] [Citation(s) in RCA: 194] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2011] [Revised: 02/07/2012] [Accepted: 02/08/2012] [Indexed: 12/20/2022]
Abstract
Most animals are sexually dimorphic, but different taxa have different sex-specific traits. Despite major differences in the genetic control of sexual development among animal lineages, the doublesex/mab-3 related (Dmrt) family of transcription factors has been shown to be involved in sex-specific differentiation in all animals that have been studied. In recent years the functions of Dmrt genes have been characterized in many animal groups, opening the way to a broad comparative perspective. This review focuses on the similarities and differences in the functions of Dmrt genes across the animal kingdom. I highlight a number of common themes in the sexual development of different taxa, discuss how Dmrt genes have acquired new roles during animal evolution, and show how they have contributed to the origin of novel sex-specific traits.
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Affiliation(s)
- Artyom Kopp
- Department of Evolution and Ecology, University of California-Davis, Davis, CA 95616 USA.
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Matson CK, Zarkower D. Sex and the singular DM domain: insights into sexual regulation, evolution and plasticity. Nat Rev Genet 2012; 13:163-74. [PMID: 22310892 PMCID: PMC3595575 DOI: 10.1038/nrg3161] [Citation(s) in RCA: 254] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Most animals reproduce sexually, but the genetic and molecular mechanisms that determine the eventual sex of each embryo vary remarkably. DM domain genes, which are related to the insect gene doublesex, are integral to sexual development and its evolution in many metazoans. Recent studies of DM domain genes reveal mechanisms by which new sexual dimorphisms have evolved in invertebrates and show that one gene, Dmrt1, was central to multiple evolutionary transitions between sex-determining mechanisms in vertebrates. In addition, Dmrt1 coordinates a surprising array of distinct cell fate decisions in the mammalian gonad and even guards against transdifferentiation of male cells into female cells in the adult testis.
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Affiliation(s)
- Clinton K Matson
- Department of Genetics, Cell Biology, and Development, University of Minnesota, 6-160 Jackson Hall, 321 Church Street SE, Minneapolis, Minnesota 55455, USA
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Rockman MV. The QTN program and the alleles that matter for evolution: all that's gold does not glitter. Evolution 2011; 66:1-17. [PMID: 22220860 DOI: 10.1111/j.1558-5646.2011.01486.x] [Citation(s) in RCA: 462] [Impact Index Per Article: 35.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The search for the alleles that matter, the quantitative trait nucleotides (QTNs) that underlie heritable variation within populations and divergence among them, is a popular pursuit. But what is the question to which QTNs are the answer? Although their pursuit is often invoked as a means of addressing the molecular basis of phenotypic evolution or of estimating the roles of evolutionary forces, the QTNs that are accessible to experimentalists, QTNs of relatively large effect, may be uninformative about these issues if large-effect variants are unrepresentative of the alleles that matter. Although 20th century evolutionary biology generally viewed large-effect variants as atypical, the field has recently undergone a quiet realignment toward a view of readily discoverable large-effect alleles as the primary molecular substrates for evolution. I argue that neither theory nor data justify this realignment. Models and experimental findings covering broad swaths of evolutionary phenomena suggest that evolution often acts via large numbers of small-effect polygenes, individually undetectable. Moreover, these small-effect variants are different in kind, at the molecular level, from the large-effect alleles accessible to experimentalists. Although discoverable QTNs address some fundamental evolutionary questions, they are essentially misleading about many others.
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Affiliation(s)
- Matthew V Rockman
- Department of Biology and Center for Genomics and Systems Biology, New York University, 12 Waverly Place, New York, NY 10003, USA.
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Siehr MS, Koo PK, Sherlekar AL, Bian X, Bunkers MR, Miller RM, Portman DS, Lints R. Multiple doublesex-related genes specify critical cell fates in a C. elegans male neural circuit. PLoS One 2011; 6:e26811. [PMID: 22069471 PMCID: PMC3206049 DOI: 10.1371/journal.pone.0026811] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Accepted: 10/04/2011] [Indexed: 11/18/2022] Open
Abstract
Background In most animal species, males and females exhibit differences in behavior and morphology that relate to their respective roles in reproduction. DM (Doublesex/MAB-3) domain transcription factors are phylogenetically conserved regulators of sexual development. They are thought to establish sexual traits by sex-specifically modifying the activity of general developmental programs. However, there are few examples where the details of these interactions are known, particularly in the nervous system. Methodology/Principal Findings In this study, we show that two C. elegans DM domain genes, dmd-3 and mab-23, regulate sensory and muscle cell development in a male neural circuit required for mating. Using genetic approaches, we show that in the circuit sensory neurons, dmd-3 and mab-23 establish the correct pattern of dopaminergic (DA) and cholinergic (ACh) fate. We find that the ETS-domain transcription factor gene ast-1, a non-sex-specific, phylogenetically conserved activator of dopamine biosynthesis gene transcription, is broadly expressed in the circuit sensory neuron population. However, dmd-3 and mab-23 repress its activity in most cells, promoting ACh fate instead. A subset of neurons, preferentially exposed to a TGF-beta ligand, escape this repression because signal transduction pathway activity in these cells blocks dmd-3/mab-23 function, allowing DA fate to be established. Through optogenetic and pharmacological approaches, we show that the sensory and muscle cell characteristics controlled by dmd-3 and mab-23 are crucial for circuit function. Conclusions/Significance In the C. elegans male, DM domain genes dmd-3 and mab-23 regulate expression of cell sub-type characteristics that are critical for mating success. In particular, these factors limit the number of DA neurons in the male nervous system by sex-specifically regulating a phylogenetically conserved dopamine biosynthesis gene transcription factor. Homologous interactions between vertebrate counterparts could regulate sex differences in neuron sub-type populations in the brain.
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Affiliation(s)
- Meagan S. Siehr
- Department of Biology, Texas A & M University, College Station, Texas, United States of America
| | - Pamela K. Koo
- Department of Biology, Texas A & M University, College Station, Texas, United States of America
| | - Amrita L. Sherlekar
- Department of Biology, Texas A & M University, College Station, Texas, United States of America
| | - Xuelin Bian
- Department of Biology, Texas A & M University, College Station, Texas, United States of America
| | - Meredith R. Bunkers
- Department of Biology, Texas A & M University, College Station, Texas, United States of America
| | - Renee M. Miller
- Department of Biomedical Genetics, Center for Neural Development and Disease, University of Rochester, Rochester, New York, United States of America
| | - Douglas S. Portman
- Department of Biomedical Genetics, Center for Neural Development and Disease, University of Rochester, Rochester, New York, United States of America
| | - Robyn Lints
- Department of Biology, Texas A & M University, College Station, Texas, United States of America
- * E-mail:
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Hou Y, Zhou X, Liu J, Yuan J, Cheng H, Zhou R. Nuclear factor-Y (NF-Y) regulates transcription of mouse Dmrt7 gene by binding to tandem CCAAT boxes in its proximal promoter. Int J Biol Sci 2010; 6:655-64. [PMID: 21060727 PMCID: PMC2974168 DOI: 10.7150/ijbs.6.655] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2010] [Accepted: 10/23/2010] [Indexed: 02/01/2023] Open
Abstract
Dmrt7, a member of the Dmrt family of genes, is required for spermatogenesis. However, promoter functions of the gene Dmrt7 remain unknown. We have cloned and characterized the proximal promoter region of the mouse Dmrt7 gene. Functional analysis of the 5' flanking region by sequential deletion mutations revealed crucial positive elements between -60 and +1, in which two highly conserved and tandem CCAAT boxes: the CCAAT box1 (-48/-44) and the CCAAT box2 (-7/-3) are located. Site-directed mutagenesis studies demonstrated that both CCAAT boxes are indispensable to the promoter activity. Electrophoretic mobility shift assays (EMSAs) and gel-supershift assays indicated that transcription factor NF-Y binds to the promoter. Chromatin immunoprecipitation (ChIP) analysis demonstrated that NF-Y interacts in vivo with the promoter of the Dmrt7 gene in testis. Co-transfection and reporter analysis showed that over-expression of NF-Ys increased transcription of the Dmrt7-luc gene whereas expression of a dominant-negative NF-Ya decreased the transcription. This suggests that NF-Y can activate the Dmrt7 promoter. These results provide evidence of a transcription regulatory mechanism that controls Dmrt7 gene expression in mouse testis.
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Affiliation(s)
- Yu Hou
- Department of Genetics, College of Life Sciences, Wuhan University, Wuhan 430072, PR China
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40
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Roberts AF, Gumienny TL, Gleason RJ, Wang H, Padgett RW. Regulation of genes affecting body size and innate immunity by the DBL-1/BMP-like pathway in Caenorhabditis elegans. BMC DEVELOPMENTAL BIOLOGY 2010; 10:61. [PMID: 20529267 PMCID: PMC2894779 DOI: 10.1186/1471-213x-10-61] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/18/2009] [Accepted: 06/07/2010] [Indexed: 11/10/2022]
Abstract
BACKGROUND Bone morphogenetic proteins (BMPs) are members of the conserved transforming growth factor beta (TGFbeta superfamily, and play many developmental and homeostatic roles. In C. elegans, a BMP-like pathway, the DBL-1 pathway, controls body size and is involved in innate immunity. How these functions are carried out, though, and what most of the downstream targets of this pathway are, remain unknown. RESULTS We performed a microarray analysis and compared expression profiles of animals lacking the SMA-6 DBL-1 receptor, which decreases pathway signaling, with animals that overexpress DBL-1 ligand, which increases pathway signaling. Consistent with a role for DBL-1 in control of body size, we find positive regulation by DBL-1 of genes involved in physical structure, protein synthesis and degradation, and metabolism. However, cell cycle genes were mostly absent from our results. We also identified genes in a hedgehog-related pathway, which may comprise a secondary signaling pathway downstream of DBL-1 that controls body size. In addition, DBL-1 signaling up-regulates pro-innate immunity genes. We identified a reporter for DBL-1 signaling, which is normally repressed but is up-regulated when DBL-1 signaling is reduced. CONCLUSIONS Our results indicate that body size in C. elegans is controlled in part by regulation of metabolic processes as well as protein synthesis and degradation. This supports the growing body of evidence that suggests cell size is linked to metabolism. Furthermore, this study discovered a possible role for hedgehog-related pathways in transmitting the BMP-like signal from the hypodermis, where the core DBL-1 pathway components are required, to other tissues in the animal. We also identified the up-regulation of genes involved in innate immunity, clarifying the role of DBL-1 in innate immunity. One of the highly regulated genes is expressed at very low levels in wild-type animals, but is strongly up-regulated in Sma/Mab mutants, making it a useful reporter for DBL-1/BMP-like signaling in C. elegans.
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Affiliation(s)
- Andrew F Roberts
- Waksman Institute, Department of Molecular Biology and Biochemistry, Cancer Institute of New Jersey, Rutgers University, Piscataway, NJ 08854-8020, USA
- Current Address: International Life Sciences Institute (ILSI) Research Foundation, Washington D.C. 20005, USA
| | - Tina L Gumienny
- Waksman Institute, Department of Molecular Biology and Biochemistry, Cancer Institute of New Jersey, Rutgers University, Piscataway, NJ 08854-8020, USA
- Current Address: Department of Molecular and Cellular Medicine, Texas A&M Health Science Center, College Station, TX 77843-1114, USA
| | - Ryan J Gleason
- Waksman Institute, Department of Molecular Biology and Biochemistry, Cancer Institute of New Jersey, Rutgers University, Piscataway, NJ 08854-8020, USA
| | - Huang Wang
- Waksman Institute, Department of Molecular Biology and Biochemistry, Cancer Institute of New Jersey, Rutgers University, Piscataway, NJ 08854-8020, USA
| | - Richard W Padgett
- Waksman Institute, Department of Molecular Biology and Biochemistry, Cancer Institute of New Jersey, Rutgers University, Piscataway, NJ 08854-8020, USA
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The DM domain transcription factor MAB-3 regulates male hypersensitivity to oxidative stress in Caenorhabditis elegans. Mol Cell Biol 2010; 30:3453-9. [PMID: 20498281 DOI: 10.1128/mcb.01459-09] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Sex differences occur in most species and involve a variety of biological characteristics. The nematode Caenorhabditis elegans consists of two sexes, self-fertile hermaphrodites (XX) and males (XO). Males differ from hermaphrodites in morphology, behavior, and life span. Here, we find that male C. elegans worms are much more sensitive than hermaphrodites to oxidative stress and show that the DM domain transcription factor MAB-3 plays a pivotal role in determining this male hypersensitivity. The hypersensitivity to oxidative stress does not depend on the dosage of X chromosomes but is determined by the somatic sex determination pathway. Our analyses show that the male hypersensitivity is controlled by MAB-3, one of the downstream effectors of the master terminal switch TRA-1 in the sex determination pathway. Moreover, we find that MAB-3 suppresses expression of several transcriptional target genes of the ELT-2 GATA factor, which is a global regulator of transcription in the C. elegans intestine, and show that RNA interference (RNAi) against elt-2 increases sensitivity to oxidative stress. These results strongly suggest that the DM domain protein MAB-3 regulates oxidative stress sensitivity by repressing transcription of ELT-2 target genes in the intestine.
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Cao P, Yuan Y, Pehek EA, Moise AR, Huang Y, Palczewski K, Feng Z. Alpha-synuclein disrupted dopamine homeostasis leads to dopaminergic neuron degeneration in Caenorhabditis elegans. PLoS One 2010; 5:e9312. [PMID: 20174477 PMCID: PMC2824852 DOI: 10.1371/journal.pone.0009312] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2009] [Accepted: 01/28/2010] [Indexed: 12/01/2022] Open
Abstract
Disruption of dopamine homeostasis may lead to dopaminergic neuron degeneration, a proposed explanation for the specific vulnerability of dopaminergic neurons in Parkinson's disease. While expression of human α-synuclein in C. elegans results in dopaminergic neuron degeneration, the effects of α-synuclein on dopamine homeostasis and its contribution to dopaminergic neuron degeneration in C. elegans have not been reported. Here, we examined the effects of α-synuclein overexpression on worm dopamine homeostasis. We found that α-synuclein expression results in upregulation of dopamine synthesis and content, and redistribution of dopaminergic synaptic vesicles, which significantly contribute to dopaminergic neuron degeneration. These results provide in vivo evidence supporting a critical role for dopamine homeostasis in supporting dopaminergic neuron integrity.
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Affiliation(s)
- Pengxiu Cao
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Yiyuan Yuan
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Elizabeth A. Pehek
- Departments of Psychiatry and Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
- Department of Veterans Affairs, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, Ohio, United States of America
| | - Alex R. Moise
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Ying Huang
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Krzysztof Palczewski
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Zhaoyang Feng
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
- Department of Physiology, College of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi, China
- * E-mail:
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Chasnov JR. The evolution from females to hermaphrodites results in a sexual conflict over mating in androdioecious nematode worms and clam shrimp. J Evol Biol 2010; 23:539-56. [PMID: 20074309 DOI: 10.1111/j.1420-9101.2009.01919.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The nematode worm Caenorhabditis elegans and the clam shrimp Eulimnadia texana are two well-studied androdioecious species consisting mostly of self-fertilizing hermaphrodites and few males. To understand how androdioecy can evolve, a simple two-step mathematical model of the evolutionary pathway from a male-female species to a selfing-hermaphrodite species is constructed. First, the frequency of mutant females capable of facultative self-fertilization increases if the benefits of reproductive assurance exceed the cost. Second, hermaphrodites become obligate self-fertilizers if the fitness of selfed offspring exceeds one-half the fitness of outcrossed offspring. Genetic considerations specific to C. elegans and E. texana show that males may endure as descendants of the ancestral male-female species. These models combined with an extensive literature review suggest a sexual conflict over mating in these androdioecious species: selection favours hermaphrodites that self and males that outcross. The strength of selection on hermaphrodites and males differs, however. Males that fail to outcross suffer a genetic death. Hermaphrodites may never encounter a rare male, and those that do and outcross only bear less fecund offspring. This asymmetric sexual conflict results in an evolutionary stand-off: rare, but persistent males occasionally fertilize common, but reluctant hermaphrodites. A consequence of this stand-off may be an increase in the longevity of the androdioecious mating system.
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Affiliation(s)
- J R Chasnov
- Department of Mathematics, Hong Kong University of Science and Technology, Kowloon, Hong Kong.
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44
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Molecular cloning and sexually dimorphic expression of DMRT4 gene in Oreochromis aureus. Mol Biol Rep 2009; 37:2781-8. [DOI: 10.1007/s11033-009-9820-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2009] [Accepted: 09/03/2009] [Indexed: 10/20/2022]
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Rockman MV, Kruglyak L. Recombinational landscape and population genomics of Caenorhabditis elegans. PLoS Genet 2009; 5:e1000419. [PMID: 19283065 PMCID: PMC2652117 DOI: 10.1371/journal.pgen.1000419] [Citation(s) in RCA: 285] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2008] [Accepted: 02/12/2009] [Indexed: 01/10/2023] Open
Abstract
Recombination rate and linkage disequilibrium, the latter a function of population genomic processes, are the critical parameters for mapping by linkage and association, and their patterns in Caenorhabditis elegans are poorly understood. We performed high-density SNP genotyping on a large panel of recombinant inbred advanced intercross lines (RIAILs) of C. elegans to characterize the landscape of recombination and, on a panel of wild strains, to characterize population genomic patterns. We confirmed that C. elegans autosomes exhibit discrete domains of nearly constant recombination rate, and we show, for the first time, that the pattern holds for the X chromosome as well. The terminal domains of each chromosome, spanning about 7% of the genome, exhibit effectively no recombination. The RIAILs exhibit a 5.3-fold expansion of the genetic map. With median marker spacing of 61 kb, they are a powerful resource for mapping quantitative trait loci in C. elegans. Among 125 wild isolates, we identified only 41 distinct haplotypes. The patterns of genotypic similarity suggest that some presumed wild strains are laboratory contaminants. The Hawaiian strain, CB4856, exhibits genetic isolation from the remainder of the global population, whose members exhibit ample evidence of intercrossing and recombining. The population effective recombination rate, estimated from the pattern of linkage disequilibrium, is correlated with the estimated meiotic recombination rate, but its magnitude implies that the effective rate of outcrossing is extremely low, corroborating reports of selection against recombinant genotypes. Despite the low population, effective recombination rate and extensive linkage disequilibrium among chromosomes, which are techniques that account for background levels of genomic similarity, permit association mapping in wild C. elegans strains. C. elegans is a model system for diverse fields of biology, but its ability to serve as a model for quantitative trait gene mapping depends on its recombination rate in the laboratory and in nature. The latter is a function of how worms mate and migrate in the wild. We examined the patterns of recombination in a population that we put through thousands of meioses in the laboratory and in a collection of strains isolated from nature. The data suggest that meiotic recombination rate is highly regular in worms, with discrete domains whose boundaries we identify. The pattern in natural strains suggests that population structure, population size, outcrossing rate, and selection combine to suppress the overall effects of recombination. Moreover, some “wild” strains appear to be laboratory contaminants. Nevertheless, the history of recombination in wild worms is sufficient to permit correlations between genotype and phenotype to pinpoint the loci responsible for phenotypic variation.
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Affiliation(s)
- Matthew V. Rockman
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, United States of America
- Department of Biology, New York University, New York, New York, United States of America
- Center for Genomics and Systems Biology, New York University, New York, New York, United States of America
- * E-mail: (MVR); (LK)
| | - Leonid Kruglyak
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, United States of America
- Howard Hughes Medical Institute, Chevy Chase, Maryland, United States of America
- * E-mail: (MVR); (LK)
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Gravato-Nobre MJ, Hodgkin J. The acyltransferase gene bus-1 exhibits conserved and specific expression in nematode rectal cells and reveals pathogen-induced cell swelling. Dev Dyn 2009; 237:3762-76. [PMID: 19035336 DOI: 10.1002/dvdy.21792] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Susceptibility to the rectal pathogen Microbacterium nematophilum provides a means of examining hindgut differentiation in C. elegans. Mutants of bus-1 are resistant to infection with this pathogen. We show here that bus-1 encodes a predicted acyltransferase expressed in rectal epithelial cells (K, F, and U), suggesting its involvement in regional surface modification. bus-1 reporter genes were used to show spatial regulation by hindgut developmental control genes: egl-38, mab-9, and mab-23. A bus-1::GFP reporter reveals the conspicuous rectal epithelial swelling induced by M. nematophilum. The C. briggsae ortholog of bus-1 exhibits conserved function and rectal expression, but it is expressed in vulval as well as rectal cells, correlated with pathogen adhesion to both vulval and rectal cells in this species. Another acyltransferase affecting bacterial adhesion, bus-18/acl-10, was also identified, which also shows strong rectal expression, but it is expressed in additional epithelial tissues and is required for general surface integrity.
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Abstract
In the nematode Caenorhabditis elegans, a single gene (plg-1) encodes the dominant protein found in mating plugs - a means of inhibiting multiple matings. Naturally occurring loss of plg-1 function results in males that fail to deposit mating plugs - a manifestation of relaxed sexual selection since the evolution of self-fertilization in this species.
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Affiliation(s)
- Asher D Cutter
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON M5S 3B2, Canada.
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Copulation in C. elegans males requires a nuclear hormone receptor. Dev Biol 2008; 322:11-20. [DOI: 10.1016/j.ydbio.2008.06.034] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2007] [Revised: 06/20/2008] [Accepted: 06/27/2008] [Indexed: 11/20/2022]
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Palopoli MF, Rockman MV, TinMaung A, Ramsay C, Curwen S, Aduna A, Laurita J, Kruglyak L. Molecular basis of the copulatory plug polymorphism in Caenorhabditis elegans. Nature 2008; 454:1019-22. [PMID: 18633349 PMCID: PMC2597896 DOI: 10.1038/nature07171] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2008] [Accepted: 06/13/2008] [Indexed: 11/08/2022]
Abstract
Heritable variation is the raw material for evolutionary change, and understanding its genetic basis is one of the central problems in modern biology. We investigated the genetic basis of a classic phenotypic dimorphism in the nematode Caenorhabditis elegans. Males from many natural isolates deposit a copulatory plug after mating, whereas males from other natural isolates?including the standard wild-type strain (N2 Bristol) that is used in most research laboratories?do not deposit plugs. The copulatory plug is a gelatinous mass that covers the hermaphrodite vulva, and its deposition decreases the mating success of subsequent males. We show that the plugging polymorphism results from the insertion of a retrotransposon into an exon of a novel mucin-like gene, plg-1, whose product is a major structural component of the copulatory plug. The gene is expressed in a subset of secretory cells of the male somatic gonad, and its loss has no evident effects beyond the loss of male mate-guarding. Although C. elegans descends from an obligate-outcrossing, male?female ancestor, it occurs primarily as self-fertilizing hermaphrodites. The reduced selection on male?male competition associated with the origin of hermaphroditism may have permitted the global spread of a loss-of-function mutation with restricted pleiotropy.
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Affiliation(s)
- Michael F Palopoli
- Department of Biology, Bowdoin College, 6500 College Station, Brunswick, Maine 04011, USA.
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