1
|
Rams-Pociecha I, Mizia PC, Piprek RP. Histological Analysis of Gonadal Ridge Development and Sex Differentiation of Gonads in Three Gecko Species. BIOLOGY 2023; 13:7. [PMID: 38248438 PMCID: PMC10813461 DOI: 10.3390/biology13010007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2023] [Revised: 12/16/2023] [Accepted: 12/19/2023] [Indexed: 01/23/2024]
Abstract
Reptiles constitute a highly diverse group of vertebrates, with their evolutionary lineages having diverged relatively early. The types of sex determination exemplify the diversity of reptiles; however, there are limited data regarding the gonadal development in squamate reptiles. Geckos constitute a group that is increasingly used in research and that serves as a potential reptilian model organism. The aim of this study was to trace the changes in the structure of developing gonads in the embryos of three gecko species: the crested gecko, leopard gecko, and mourning gecko. These species represent different families of the Gekkota infraorder and exhibit different types of sex determination. Gonadal development was examined from the formation of the earliest gonadal ridges through the development of undifferentiated gonadal structures, sex differentiation of gonads, and the formation of testicular and ovarian structures. The study showed that the gonadal primordia of these three gecko species formed on the most dorsally located surface of the dorsal mesentery, and both the coelomic epithelium and the nephric mesenchyme contributed to their development. As in other reptile species, primordial germ cells settled in the gonadal ridges, and the undifferentiated gonad was composed of a cortex and a medulla. Ovarian differentiation started with the thickening of the gonadal cortex and proliferation of germ cells in this region. A characteristic feature of the developing gecko ovaries was the thickened crescent-shaped cortex on the medial and ventral surfaces of the ovaries. The ovarian medulla also grew and exhibited diverse tendencies to form cords. In the leopard gecko, advanced cord-like structures with lumens were observed in the ovaries, which were not seen in the crested gecko. Testicular differentiation was characterized by cortical thinning and the disappearance of germ cells in this region. In the medulla, the development of distinct cords with early lumen formation was noted. A characteristic feature of embryonic gonads was their growth in a horizontal plane. In this study, gonadal development was characterized by several features that are shared by geckos and other reptiles, along with features that are specific only to geckos.
Collapse
Affiliation(s)
- Izabela Rams-Pociecha
- Department of Comparative Anatomy, Institute of Zoology and Biomedical Research, Jagiellonian University, 30-387 Krakow, Poland; (I.R.-P.); (P.C.M.)
- Doctoral School of Exact and Natural Sciences, Jagiellonian University, 30-348 Krakow, Poland
| | - Paulina C. Mizia
- Department of Comparative Anatomy, Institute of Zoology and Biomedical Research, Jagiellonian University, 30-387 Krakow, Poland; (I.R.-P.); (P.C.M.)
- Doctoral School of Exact and Natural Sciences, Jagiellonian University, 30-348 Krakow, Poland
| | - Rafal P. Piprek
- Department of Comparative Anatomy, Institute of Zoology and Biomedical Research, Jagiellonian University, 30-387 Krakow, Poland; (I.R.-P.); (P.C.M.)
| |
Collapse
|
2
|
Smaga CR, Bock SL, Johnson JM, Parrott BB. Sex Determination and Ovarian Development in Reptiles and Amphibians: From Genetic Pathways to Environmental Influences. Sex Dev 2022; 17:99-119. [PMID: 36380624 DOI: 10.1159/000526009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 07/08/2022] [Indexed: 11/21/2023] Open
Abstract
BACKGROUND Reptiles and amphibians provide untapped potential for discovering how a diversity of genetic pathways and environmental conditions are incorporated into developmental processes that can lead to similar functional outcomes. These groups display a multitude of reproductive strategies, and whereas many attributes are conserved within groups and even across vertebrates, several aspects of sexual development show considerable variation. SUMMARY In this review, we focus our attention on the development of the reptilian and amphibian ovary. First, we review and describe the events leading to ovarian development, including sex determination and ovarian maturation, through a comparative lens. We then describe how these events are influenced by environmental factors, focusing on temperature and exposure to anthropogenic chemicals. Lastly, we identify critical knowledge gaps and future research directions that will be crucial to moving forward in our understanding of ovarian development and the influences of the environment in reptiles and amphibians. KEY MESSAGES Reptiles and amphibians provide excellent models for understanding the diversity of sex determination strategies and reproductive development. However, a greater understanding of the basic biology of these systems is necessary for deciphering the adaptive and potentially disruptive implications of embryo-by-environment interactions in a rapidly changing world.
Collapse
Affiliation(s)
- Christopher R Smaga
- Eugene P. Odum School of Ecology, University of Georgia, Athens, Georgia, USA
- Savannah River Ecology Laboratory, Aiken, South Carolina, USA
| | - Samantha L Bock
- Eugene P. Odum School of Ecology, University of Georgia, Athens, Georgia, USA
- Savannah River Ecology Laboratory, Aiken, South Carolina, USA
| | - Josiah M Johnson
- Eugene P. Odum School of Ecology, University of Georgia, Athens, Georgia, USA
- Savannah River Ecology Laboratory, Aiken, South Carolina, USA
| | - Benjamin B Parrott
- Eugene P. Odum School of Ecology, University of Georgia, Athens, Georgia, USA
- Savannah River Ecology Laboratory, Aiken, South Carolina, USA
| |
Collapse
|
3
|
Comparative transcriptomic analysis reveals the gonadal development-related gene response to environmental temperature in Mauremys mutica. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY D-GENOMICS & PROTEOMICS 2021; 40:100925. [PMID: 34689019 DOI: 10.1016/j.cbd.2021.100925] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 10/11/2021] [Accepted: 10/14/2021] [Indexed: 01/15/2023]
Abstract
The Asian yellow pond turtle (Mauremys mutica) displays temperature-dependent sex determination (TSD), in which incubation temperature during embryonic development determines the sexual fate of the individual. However, the mechanism of the sex determination/differentiation of Mauremys mutica remains a mystery. Here, we first analyzed the temperature-specific gonadal transcriptomes of Mauremys mutica prior to gonad formation and gonads during the thermosensitive period. We uncovered a list of candidates that respond to temperature stimuli enriched in several categories, such as heat shock protein family members dnajb6a, dnaja4, hspa8 and hsp90aa1, temperature sensor genes mmp17 and mmp28, and putative novel temperature-responsive genes tmco6, gria3 and eif3f. Notably, striking differences were identified in the expression profiles of genes underlying sexual development, such as tex15, insr, igf1r, cirbp, esr1, dmrt2 and Serpinh1. Moreover, we analyzed the similarity and divergence of the timecourse of gene expression among Mauremys mutica and two other reported TSD turtles (Trachemys scripta and Chrysemys picta). The shared genes revealed the common gonad-specific regulatory mechanisms existing in these three TSD turtles that initiate their sexual development. Therefore, our findings could provide basic data to elucidate the mechanisms of sex determination/differentiation of M. mutica, even contributing to further understanding of these mechanisms in other TSD turtles.
Collapse
|
4
|
Merchant-Larios H, Díaz-Hernández V, Cortez D. Molecular and Cellular Mechanisms Underlying Temperature-Dependent Sex Determination in Turtles. Sex Dev 2021; 15:38-46. [PMID: 34167126 DOI: 10.1159/000515296] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 02/16/2021] [Indexed: 11/19/2022] Open
Abstract
The discovery in mammals that fetal testes are required in order to develop the male phenotype inspired research efforts to elucidate the mechanisms underlying gonadal sex determination and differentiation in vertebrates. A pioneer work in 1966 that demonstrated the influence of incubation temperature on sexual phenotype in some reptilian species triggered great interest in the environment's role as a modulator of plasticity in sex determination. Several chelonian species have been used as animal models to test hypotheses concerning the mechanisms involved in temperature-dependent sex determination (TSD). This brief review intends to outline the history of scientific efforts that corroborate our current understanding of the state-of-the-art in TSD using chelonian species as a reference.
Collapse
Affiliation(s)
- Horacio Merchant-Larios
- Instituto de Investigaciones Biomédicas, Departamento de Biología Celular y Fisiología, Universidad Nacional Autónoma de México, Mexico city, Mexico
| | - Verónica Díaz-Hernández
- Facultad de Medicina, Departamento de Embriología, Universidad Nacional Autónoma de México, Mexico city, Mexico
| | - Diego Cortez
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| |
Collapse
|
5
|
Nagahama Y, Chakraborty T, Paul-Prasanth B, Ohta K, Nakamura M. Sex determination, gonadal sex differentiation, and plasticity in vertebrate species. Physiol Rev 2020; 101:1237-1308. [PMID: 33180655 DOI: 10.1152/physrev.00044.2019] [Citation(s) in RCA: 87] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
A diverse array of sex determination (SD) mechanisms, encompassing environmental to genetic, have been found to exist among vertebrates, covering a spectrum from fixed SD mechanisms (mammals) to functional sex change in fishes (sequential hermaphroditic fishes). A major landmark in vertebrate SD was the discovery of the SRY gene in 1990. Since that time, many attempts to clone an SRY ortholog from nonmammalian vertebrates remained unsuccessful, until 2002, when DMY/dmrt1by was discovered as the SD gene of a small fish, medaka. Surprisingly, however, DMY/dmrt1by was found in only 2 species among more than 20 species of medaka, suggesting a large diversity of SD genes among vertebrates. Considerable progress has been made over the last 3 decades, such that it is now possible to formulate reasonable paradigms of how SD and gonadal sex differentiation may work in some model vertebrate species. This review outlines our current understanding of vertebrate SD and gonadal sex differentiation, with a focus on the molecular and cellular mechanisms involved. An impressive number of genes and factors have been discovered that play important roles in testicular and ovarian differentiation. An antagonism between the male and female pathway genes exists in gonads during both sex differentiation and, surprisingly, even as adults, suggesting that, in addition to sex-changing fishes, gonochoristic vertebrates including mice maintain some degree of gonadal sexual plasticity into adulthood. Importantly, a review of various SD mechanisms among vertebrates suggests that this is the ideal biological event that can make us understand the evolutionary conundrums underlying speciation and species diversity.
Collapse
Affiliation(s)
- Yoshitaka Nagahama
- Laboratory of Reproductive Biology, National Institute for Basic Biology, Okazaki, Japan.,South Ehime Fisheries Research Center, Ehime University, Ainan, Japan.,Faculty of Biological Science and Technology, Kanazawa University, Ishikawa, Japan
| | - Tapas Chakraborty
- Laboratory of Reproductive Biology, National Institute for Basic Biology, Okazaki, Japan.,South Ehime Fisheries Research Center, Ehime University, Ainan, Japan.,Laboratory of Marine Biology, Faculty of Agriculture, Kyushu University, Fukouka, Japan.,Karatsu Satellite of Aqua-Bioresource Innovation Center, Kyushu University, Karatsu, Japan
| | - Bindhu Paul-Prasanth
- Laboratory of Reproductive Biology, National Institute for Basic Biology, Okazaki, Japan.,Centre for Nanosciences and Molecular Medicine, Amrita Vishwa Vidapeetham, Kochi, Kerala, India
| | - Kohei Ohta
- Laboratory of Marine Biology, Faculty of Agriculture, Kyushu University, Fukouka, Japan
| | - Masaru Nakamura
- Sesoko Station, Tropical Biosphere Research Center, University of the Ryukyus, Okinawa, Japan.,Research Center, Okinawa Churashima Foundation, Okinawa, Japan
| |
Collapse
|
6
|
Ultrastructural analysis of the yolk processing pattern in embryonic pond slider turtles (Trachemys scripta: Emydidae). JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2019; 332:187-197. [DOI: 10.1002/jez.b.22894] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 06/19/2019] [Accepted: 06/27/2019] [Indexed: 01/19/2023]
|
7
|
Xiong L, Dong J, Jiang H, Zan J, Tong J, Liu J, Wang M, Nie L. Transcriptome sequencing and comparative analysis of adult ovary and testis identify potential gonadal maintenance-related genes in Mauremys reevesii with temperature-dependent sex determination. PeerJ 2019; 7:e6557. [PMID: 30867990 PMCID: PMC6410691 DOI: 10.7717/peerj.6557] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 02/03/2019] [Indexed: 01/09/2023] Open
Abstract
Mauremys reevesii is a classical organism with temperature-dependent sex determination (TSD). Gonad development in early life has recently received considerable attention but gonadal maintenance after sex differentiation in turtles with TSD remains a mystery. In this study, we sequenced the transcriptomes for the adult testis and ovary using RNA-seq, and 36,221 transcripts were identified. In total, 1,594 differentially expressed genes (DEGs) were identified where 756 DEGs were upregulated in the testis and 838 DEGs were upregulated in the ovary. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analysis suggested that the TGF-beta signaling pathway and Hedgehog signaling pathway have important roles in testis maintenance and spermatogenesis, whereas the Hippo signaling pathway and Wnt signaling pathway are likely to participate in ovary maintenance. We determined the existence of antagonistic networks containing significant specific-expressed genes and pathways related to gonadal maintenance and gametogenesis in the adult gonads of M. reevesii. The candidate gene Fibronectin type 3 and ankyrin repeat domains 1 (FANK1) might be involved with the regulation of testis spermatogenesis.
Collapse
Affiliation(s)
- Lei Xiong
- Life Science College of Anhui Normal University, Provincial Key Lab of the Conservation and Exploitation Research of Biological Resources in Anhui, Wuhu, Anhui, P.R. China.,Biochemistry Department of Wannan Medical College, Provincial Key Laboratory of Biological Macro-molecules Research, Wuhu, Anhui, P.R. China
| | - Jinxiu Dong
- Life Science College of Anhui Normal University, Provincial Key Lab of the Conservation and Exploitation Research of Biological Resources in Anhui, Wuhu, Anhui, P.R. China
| | - Hui Jiang
- Life Science College of Anhui Normal University, Provincial Key Lab of the Conservation and Exploitation Research of Biological Resources in Anhui, Wuhu, Anhui, P.R. China
| | - Jiawei Zan
- Life Science College of Anhui Normal University, Provincial Key Lab of the Conservation and Exploitation Research of Biological Resources in Anhui, Wuhu, Anhui, P.R. China
| | - Jiucui Tong
- Life Science College of Anhui Normal University, Provincial Key Lab of the Conservation and Exploitation Research of Biological Resources in Anhui, Wuhu, Anhui, P.R. China.,Biochemistry Department of Wannan Medical College, Provincial Key Laboratory of Biological Macro-molecules Research, Wuhu, Anhui, P.R. China
| | - Jianjun Liu
- Life Science College of Anhui Normal University, Provincial Key Lab of the Conservation and Exploitation Research of Biological Resources in Anhui, Wuhu, Anhui, P.R. China
| | - Meng Wang
- Life Science College of Anhui Normal University, Provincial Key Lab of the Conservation and Exploitation Research of Biological Resources in Anhui, Wuhu, Anhui, P.R. China
| | - Liuwang Nie
- Life Science College of Anhui Normal University, Provincial Key Lab of the Conservation and Exploitation Research of Biological Resources in Anhui, Wuhu, Anhui, P.R. China
| |
Collapse
|
8
|
17β-Estradiol modulates cell proliferation of medullary cords during ovarian differentiation of the Lepidochelys olivacea sea turtle. Dev Biol 2017; 431:263-271. [PMID: 28893547 DOI: 10.1016/j.ydbio.2017.09.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 09/06/2017] [Accepted: 09/06/2017] [Indexed: 11/23/2022]
Abstract
In turtles undergoing temperature sex determination (TSD), bipotential gonads express Sox9 in medullary cords at both female- (FPT) and male-producing temperatures (MPT). Subsequently, when the sex fate of medullary cords becomes dimorphic, at FPT, Sox9 is downregulated, whereas at MPT, its expression is maintained. Medullary cords in the ovary turn into ovarian lacuna, whereas in the testis they differentiate as seminiferous cords. When embryos of Lepidochelys olivacea sea turtle are incubated at MPT and treated with estradiol, Sox9 expression persists in the medullary cords in the form of tiny ovotestis-like formations. The perturbed development of the treated gonads is due to a significant decrease in the number of proliferating cells. This suggests that the disturbed effect caused by exogenous estradiol may be due to a conflict between the gene networks regulated by temperature and the increased level of endogenous estrogens, induced by the treatment. Here, we decided to use fadrozole and fulvestrant, an aromatase inhibitor and an estrogen-receptor antagonist, respectively, to provide insights into the role played by endogenous estrogens in regulating the cell proliferation of the two main gonadal compartments: the medullary cords and the cortex. Comparing cell proliferation patterns, our current results suggest that the endogenous estrogens are involved in determining the sex fate of medullary cords, by repressing proliferation. Interestingly, our results showed that endogenous estradiol levels are unnecessary for the thickening of the ovarian cortex.
Collapse
|
9
|
Dmrt1 is required for primary male sexual differentiation in Chinese soft-shelled turtle Pelodiscus sinensis. Sci Rep 2017; 7:4433. [PMID: 28667307 PMCID: PMC5493664 DOI: 10.1038/s41598-017-04938-5] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 06/16/2017] [Indexed: 11/27/2022] Open
Abstract
In vertebrates, the primary sex-determining signals that initiate sexual development are remarkably diverse, ranging from complete genetic to environmental cues. However, no sex determination-related genes have been functionally identified in reptiles. Here, we characterized a conserved DM domain gene, Dmrt1, in Chinese soft-shelled turtle Pelodiscus sinensis (P. sinensis), which exhibits ZZ/ZW sex chromosomes. Dmrt1 exhibited early male-specific embryonic expression, preceding the onset of gonadal sex differentiation. The expression of Dmrt1 was induced in ZW embryonic gonads that were masculinized by aromatase inhibitor treatment. Dmrt1 knockdown in ZZ embryos by RNA interference resulted in male to female sex reversal, characterized by obvious feminization of gonads, significant down-regulation of testicular markers Amh and Sox9, and remarkable up-regulation of ovarian regulators, Cyp19a1 and Foxl2. Conversely, ectopic expression of Dmrt1 led to largely masculinized genetic females, production of Amh and Sox9, and a decline in Cyp19a1 and Foxl2. These findings demonstrate that Dmrt1 is both necessary and sufficient to initiate testicular development, thereby acting as an upstream regulator of the male pathway in P. sinensis.
Collapse
|
10
|
Radhakrishnan S, Literman R, Neuwald J, Severin A, Valenzuela N. Transcriptomic responses to environmental temperature by turtles with temperature-dependent and genotypic sex determination assessed by RNAseq inform the genetic architecture of embryonic gonadal development. PLoS One 2017; 12:e0172044. [PMID: 28296881 PMCID: PMC5352168 DOI: 10.1371/journal.pone.0172044] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 01/30/2017] [Indexed: 12/24/2022] Open
Abstract
Vertebrate sexual fate is decided primarily by the individual's genotype (GSD), by the environmental temperature during development (TSD), or both. Turtles exhibit TSD and GSD, making them ideal to study the evolution of sex determination. Here we analyze temperature-specific gonadal transcriptomes (RNA-sequencing validated by qPCR) of painted turtles (Chrysemys picta TSD) before and during the thermosensitive period, and at equivalent stages in soft-shell turtles (Apalone spinifera-GSD), to test whether TSD's and GSD's transcriptional circuitry is identical but deployed differently between mechanisms. Our data show that most elements of the mammalian urogenital network are active during turtle gonadogenesis, but their transcription is generally more thermoresponsive in TSD than GSD, and concordant with their sex-specific function in mammals [e.g., upregulation of Amh, Ar, Esr1, Fog2, Gata4, Igf1r, Insr, and Lhx9 at male-producing temperature, and of β-catenin, Foxl2, Aromatase (Cyp19a1), Fst, Nf-kb, Crabp2 at female-producing temperature in Chrysemys]. Notably, antagonistic elements in gonadogenesis (e.g., β-catenin and Insr) were thermosensitive only in TSD early-embryos. Cirbp showed warm-temperature upregulation in both turtles disputing its purported key TSD role. Genes that may convert thermal inputs into sex-specific development (e.g., signaling and hormonal pathways, RNA-binding and heat-shock) were differentially regulated. Jak-Stat, Nf-κB, retinoic-acid, Wnt, and Mapk-signaling (not Akt and Ras-signaling) potentially mediate TSD thermosensitivity. Numerous species-specific ncRNAs (including Xist) were differentially-expressed, mostly upregulated at colder temperatures, as were unannotated loci that constitute novel TSD candidates. Cirbp showed warm-temperature upregulation in both turtles. Consistent transcription between turtles and alligator revealed putatively-critical reptilian TSD elements for male (Sf1, Amh, Amhr2) and female (Crabp2 and Hspb1) gonadogenesis. In conclusion, while preliminary, our data helps illuminate the regulation and evolution of vertebrate sex determination, and contribute genomic resources to guide further research into this fundamental biological process.
Collapse
Affiliation(s)
- Srihari Radhakrishnan
- Bioinformatics and Computational Biology Program, Iowa State University, Ames, IA, United States of America
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA, United States of America
| | - Robert Literman
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA, United States of America
- Ecology and Evolutionary Biology Program, Iowa State University, Ames, IA, United States of America
| | - Jennifer Neuwald
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA, United States of America
| | - Andrew Severin
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA, United States of America
- Genome Informatics Facility, Iowa State University, Ames, IA, United States of America
| | - Nicole Valenzuela
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA, United States of America
| |
Collapse
|
11
|
Bertho S, Pasquier J, Pan Q, Le Trionnaire G, Bobe J, Postlethwait JH, Pailhoux E, Schartl M, Herpin A, Guiguen Y. Foxl2 and Its Relatives Are Evolutionary Conserved Players in Gonadal Sex Differentiation. Sex Dev 2016; 10:111-29. [PMID: 27441599 DOI: 10.1159/000447611] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Indexed: 11/19/2022] Open
Abstract
Foxl2 is a member of the large family of Forkhead Box (Fox) domain transcription factors. It emerged during the last 15 years as a key player in ovarian differentiation and oogenesis in vertebrates and especially mammals. This review focuses on Foxl2 genes in light of recent findings on their evolution, expression, and implication in sex differentiation in animals in general. Homologs of Foxl2 and its paralog Foxl3 are found in all metazoans, but their gene evolution is complex, with multiple gains and losses following successive whole genome duplication events in vertebrates. This review aims to decipher the evolutionary forces that drove Foxl2/3 gene specialization through sub- and neo-functionalization during evolution. Expression data in metazoans suggests that Foxl2/3 progressively acquired a role in both somatic and germ cell gonad differentiation and that a certain degree of sub-functionalization occurred after its duplication in vertebrates. This generated a scenario where Foxl2 is predominantly expressed in ovarian somatic cells and Foxl3 in male germ cells. To support this hypothesis, we provide original results showing that in the pea aphid (insects) foxl2/3 is predominantly expressed in sexual females and showing that in bovine ovaries FOXL2 is specifically expressed in granulosa cells. Overall, current results suggest that Foxl2 and Foxl3 are evolutionarily conserved players involved in somatic and germinal differentiation of gonadal sex.
Collapse
Affiliation(s)
- Sylvain Bertho
- INRA, UR1037 Fish Physiology and Genomics, Rennes, France
| | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Mizoguchi BA, Valenzuela N. Ecotoxicological Perspectives of Sex Determination. Sex Dev 2016; 10:45-57. [DOI: 10.1159/000444770] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/05/2015] [Indexed: 11/19/2022] Open
|