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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.
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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.)
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Ma X, Liu F, Chen Q, Sun W, Shen J, Wu K, Zheng Z, Huang J, Chen J, Qian G, Ge C. Foxl2 is required for the initiation of the female pathway in a temperature-dependent sex determination system in Trachemys scripta. Development 2022; 149:275948. [DOI: 10.1242/dev.200863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Accepted: 06/14/2022] [Indexed: 11/20/2022]
Abstract
ABSTRACT
KDM6B-mediated epigenetic modification of the testicular regulator Dmrt1 has previously been identified as the primary switch of the male pathway in a temperature-dependent sex-determination (TSD) system; however, the molecular network of the female pathway has not yet been established. Here, we have functionally characterized for the first time an upstream regulator of the female pathway, the forkhead transcription factor FOXL2, in Trachemys scripta, a turtle species with a TSD system. FOXL2 exhibited temperature-dependent female-specific expression patterns before the onset of gonadal differentiation and was preferentially localized in ovarian somatic cells. Foxl2 responded rapidly to temperature shifts and estrogen. Importantly, forced expression of Foxl2 at the male-producing temperature led to male-to-female sex reversal, as evidenced by the formation of an ovary-like structure, and upregulation of the ovarian regulators Cyp19a1 and R-spondin1. Additionally, knockdown of Foxl2 caused masculinization at the female-producing temperature, which was confirmed by loss of the female phenotype, development of seminiferous tubules, and elevated expression of Dmrt1 and Sox9. Collectively, we demonstrate that Foxl2 expression is necessary and sufficient to drive ovarian determination in T. scripta, suggesting a crucial role of Foxl2 in female sex determination in the TSD system.
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Affiliation(s)
- Xiaohui Ma
- College of Biological and Environmental Sciences, Zhejiang Wanli University 1 , Ningbo 315100 , China
- College of Fisheries and Life Sciences, Shanghai Ocean University 2 , Shanghai 201306 , China
| | - Fang Liu
- College of Biological and Environmental Sciences, Zhejiang Wanli University 1 , Ningbo 315100 , China
- College of Fisheries and Life Sciences, Shanghai Ocean University 2 , Shanghai 201306 , China
| | - Qiran Chen
- College of Biological and Environmental Sciences, Zhejiang Wanli University 1 , Ningbo 315100 , China
- College of Marine Life Sciences, Ocean University of China 3 MOE Key Laboratory of Marine Genetics and Breeding , , Qingdao 266003 , China
| | - Wei Sun
- College of Biological and Environmental Sciences, Zhejiang Wanli University 1 , Ningbo 315100 , China
| | - Jiadong Shen
- College of Biological and Environmental Sciences, Zhejiang Wanli University 1 , Ningbo 315100 , China
| | - Kaiyue Wu
- College of Biological and Environmental Sciences, Zhejiang Wanli University 1 , Ningbo 315100 , China
| | - Ziyan Zheng
- College of Biological and Environmental Sciences, Zhejiang Wanli University 1 , Ningbo 315100 , China
| | - Jiaqi Huang
- College of Biological and Environmental Sciences, Zhejiang Wanli University 1 , Ningbo 315100 , China
| | - Jiawen Chen
- College of Biological and Environmental Sciences, Zhejiang Wanli University 1 , Ningbo 315100 , China
| | - Guoying Qian
- College of Biological and Environmental Sciences, Zhejiang Wanli University 1 , Ningbo 315100 , China
| | - Chutian Ge
- College of Biological and Environmental Sciences, Zhejiang Wanli University 1 , Ningbo 315100 , China
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Unda-Díaz NM, Phillips-Farfán BV, Nava H, Lopez-Toledo L, Murata C, Lajud N, Herrera-Vargas MA, Arreola Camacho CA, Torner L, Fuentes-Farías AL, Meléndez-Herrera E. Negative Effects on Neurogenesis, Ovariogenesis, and Fitness in Sea Turtle Hatchlings Associated to ex situ Incubation Management. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.850612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Sea turtle egg relocation and hatchery incubation (hereafter termed ex situ incubation) is an effective strategy to protect clutches when in situ egg incubation is not viable. Nevertheless, it negatively affects the ontogenesis of male gonads and brain areas homologous to the mammalian hippocampus, as well as body size and fitness. Thus, it is imperative to analyze the effects of ex situ incubation on other developmental aspects and extend these observations to females. This work evaluated the effect of ex situ management on neurogenesis (cell proliferation in the dorsal and medial ventricular zones, neuronal integration in the dorsomedial and medial cortices), ovary cell proliferation, body size (mass and length) and self-righting ability. Additionally, this study examined if the incubation microenvironment is different between in situ and ex situ nests and whether it could contribute to explain the biological traits. An analysis of principal components showed differences in biological variables of hatchlings between in situ and ex situ clutches, driven by contrasting temperatures and silt composition. Each biological variable was also analyzed with linear mixed models using in situ vs. ex situ clutches, abiotic variables and their interaction. Turtles from ex situ clutches showed: (1) fewer proliferating cells in the dorsal and medial ventricular zones; (2) less mature neurons in the dorsomedial and medial cortices; (3) ovaries with a lesser number of proliferating cells; (4) lower body mass and length at emergence; and (5) slower self-righting time. Together, the results suggest that ex situ incubation in hatcheries is related to a slowing down of neurogenesis, ovariogenesis, body size and self-righting ability in hatchlings. Future studies should evaluate the effect of ex situ incubation on cognitive and reproductive performance to understand the long-term consequences of altered organogenesis. These studies should also disentangle the differential contribution of egg movement, reburial, nesting environment and parental origin to development. This information would likely result in better conservation strategies for sea turtles.
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Li P, Guo Y, Jin L, Liang X, Chen G, Sun W, Xiao L, Qian G, Ge C. ESR1 mediates estrogen-induced feminization of genetic male Chinese soft-shelled turtle. Biol Reprod 2022; 107:779-789. [PMID: 35512131 DOI: 10.1093/biolre/ioac088] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2022] [Revised: 04/01/2022] [Accepted: 04/29/2022] [Indexed: 11/12/2022] Open
Abstract
Exogenous estrogen have shown their femininization abilities during the specific sex differentiation period in several reptiles. However, the specific regulatory mechanism and downstream regulatory genes of estrogen remain elusive. In the present study, 17β-estradiol (E2), as well as drugs of specific antagonists and/or agonists of estrogen receptors, were employed to figure out the molecular pathway involved in the E2-induced feminization in Chinese soft-shelled turtles, an important aquaculture species in China. E2 treatment led to typical female characteristics in the gonads of ZZ individuals, including thickened outer cortex containing a number of germ cells and degenerated medullary cords, as well as the disappearance of male marker SOX9, and the ectopic expression of ovarian regulator FOXL2 at the embryonic developmental stage 27 and 1 month after hatching. The specific ESR1 antagonist or a combination of three estrogen receptor antagonists could block the sex reversal of ZZ individuals induced by estrogen. In addition, specific activation of ESR1 by agonist also led to the feminization of ZZ gonads, which was similar to the effect of estrogen treatment. Furthermore, transcriptome data showed that the expression level of FOXL2 was significantly up-regulated, while mRNA levels of DMRT1, SOX9 and AMH were down-regulated after estrogen treatment. Taken together, our results indicated that E2 induced the feminization of ZZ Chinese soft-shelled turtles via ESR1, and decrease of male genes DMRT1, SOX9and AMH and increase of ovarian development regulator FOXL2 might be responsible for the initiation of E2-induced feminization.
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Affiliation(s)
- Pan Li
- Institute of Animal Sex and Development, Zhejiang Wanli University, Ningbo, 315100, China.,College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo, 315100, China
| | - Yin Guo
- Institute of Animal Sex and Development, Zhejiang Wanli University, Ningbo, 315100, China.,College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo, 315100, China
| | - Lin Jin
- Institute of Animal Sex and Development, Zhejiang Wanli University, Ningbo, 315100, China.,College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo, 315100, China
| | - Xiao Liang
- College of Fisheries and Life Sciences, Shanghai Ocean University, Shanghai, 201306, China
| | - Gaoan Chen
- Institute of Animal Sex and Development, Zhejiang Wanli University, Ningbo, 315100, China
| | - Wei Sun
- Institute of Animal Sex and Development, Zhejiang Wanli University, Ningbo, 315100, China.,College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo, 315100, China
| | - Ling Xiao
- Institute of Animal Sex and Development, Zhejiang Wanli University, Ningbo, 315100, China.,College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo, 315100, China
| | - Guoying Qian
- College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo, 315100, China
| | - Chutian Ge
- Institute of Animal Sex and Development, Zhejiang Wanli University, Ningbo, 315100, China.,College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo, 315100, China
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Lockley EC, Eizaguirre C. Effects of global warming on species with temperature-dependent sex determination: Bridging the gap between empirical research and management. Evol Appl 2021; 14:2361-2377. [PMID: 34745331 PMCID: PMC8549623 DOI: 10.1111/eva.13226] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 03/05/2021] [Accepted: 03/11/2021] [Indexed: 12/31/2022] Open
Abstract
Global warming could threaten over 400 species with temperature-dependent sex determination (TSD) worldwide, including all species of sea turtle. During embryonic development, rising temperatures might lead to the overproduction of one sex and, in turn, could bias populations' sex ratios to an extent that threatens their persistence. If climate change predictions are correct, and biased sex ratios reduce population viability, species with TSD may go rapidly extinct unless adaptive mechanisms, whether behavioural, physiological or molecular, exist to buffer these temperature-driven effects. Here, we summarize the discovery of the TSD phenomenon and its still elusive evolutionary significance. We then review the molecular pathways underpinning TSD in model species, along with the hormonal mechanisms that interact with temperatures to determine an individual's sex. To illustrate evolutionary mechanisms that can affect sex determination, we focus on sea turtle biology, discussing both the adaptive potential of this threatened TSD taxon, and the risks associated with conservation mismanagement.
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Affiliation(s)
- Emma C. Lockley
- School of Biological and Chemical SciencesQueen Mary University LondonLondonUK
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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: 5] [Impact Index Per Article: 1.7] [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.
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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
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Cai M, Li YY, Zhu M, Li JB, Qin ZF. Evaluation of the effects of low concentrations of bisphenol AF on gonadal development using the Xenopus laevis model: A finding of testicular differentiation inhibition coupled with feminization. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 260:113980. [PMID: 31991354 DOI: 10.1016/j.envpol.2020.113980] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 01/08/2020] [Accepted: 01/12/2020] [Indexed: 06/10/2023]
Abstract
Developmental exposures to estrogenic chemicals possibly cause structural and functional abnormalities of reproductive organs in vertebrates. Bisphenol AF (BPAF), a bisphenol A (BPA) analogue, has been shown to have higher estrogenic activity than BPA, but little is known about the effects of BPAF on gonadal development, particularly gonadal differentiation. We aimed to determine whether low concentrations of BPAF could disrupt gonadal differentiation and subsequent development using Xenopus laevis, a model species for studying feminizing effects of estrogenic chemicals. X. laevis tadpoles were exposed to BPAF (1, 10, 100 nM) or 17β-estradiol (E2, positive control) from stages 45/46 to 53 and 66 in a semi-static exposure system, with a prolonged treatment with the highest concentration to the eighth week post-metamorphosis (WPM8). Gonadal morphology and histology as well as sexually dimorphic gene expression were examined to evaluate the effects of BPAF. All concentrations of BPAF caused changes in testicular morphology at different developmental stages compared with controls. Specifically, at stage 53, BPAF like E2 resulted in decreases in both the size and the number of gonadal metameres (gonomeres) in testes, looking like ovaries. Some of BPAF-treated testes remained segmented and even became discontinuous and fragmented at subsequent stages. Histological abnormalities were also observed in BPAF-treated testes, such as ovarian cavity at stages 53 and 66 and poorly developed seminiferous tubules on WPM8. At the molecular level, BPAF inhibited expression of male highly expressed genes in testes at stage 53. Correspondingly, BPAF, like E2, inhibited cell proliferation in testes at stage 50. All results show that low concentrations of BPAF inhibited testicular differentiation and subsequent development in X. laevis, along with feminizing effects to some degree. Our finding implies a risk of BPAF to the male reproductive system of vertebrates including humans.
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Affiliation(s)
- Man Cai
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yuan-Yuan Li
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Min Zhu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jin-Bo Li
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhan-Fen Qin
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
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Schroeder A, Rhen T. Role for androgens in determination of ovarian fate in the common snapping turtle, Chelydra serpentina. Gen Comp Endocrinol 2019; 281:7-16. [PMID: 31059691 PMCID: PMC6784546 DOI: 10.1016/j.ygcen.2019.05.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 03/28/2019] [Accepted: 05/02/2019] [Indexed: 02/03/2023]
Abstract
Sex steroids are involved in sex determination in almost all vertebrates, including species with temperature-dependent sex determination (TSD). It is well established that aromatase and estrogens are involved in ovary determination in TSD species. In contrast, the role of non-aromatizable androgens in TSD is less clear. In this study, we used dihydrotestosterone (DHT) and an antagonist of the mammalian androgen receptor (flutamide) to examine the impact of androgens on sex determination in the snapping turtle. We incubated eggs at a male-producing temperature and treated embryos with drug delivery vehicle (5 L ethanol), DHT in vehicle, or flutamide in vehicle during the sex-determining period. We then measured expression of markers for ovarian and testicular development and genes involved in steroidogenesis. A subset of embryos and hatchlings were collected for histological analysis of gonad differentiation and sex determination. DHT and flutamide both induced ovarian development: 100% of vehicle-treated hatchlings had testes, while 60% of DHT-treated and 32% flutamide-treated hatchlings had ovaries. DHT and flutamide treatments also had feminizing effects on gene expression patterns and the structure of embryonic gonads. DHT treatment increased expression of FoxL2, androgen receptor, aromatase and several steroidogenic genes. Flutamide produced a similar, but weaker, pattern of gene expression. Genes involved in testis development (Sox9 and Amh) were influenced by flutamide treatment. Our findings support the hypothesis that androgens and the androgen receptor are involved in ovary determination in the common snapping turtle.
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Affiliation(s)
- Anthony Schroeder
- Department of Biology, Box 9019, University of North Dakota, Grand Forks, ND 58202, United States; Math, Science, and Technology Department, 2900 University Avenue, University of Minnesota - Crookston, Crookston, MN 56716, United States
| | - Turk Rhen
- Department of Biology, Box 9019, University of North Dakota, Grand Forks, ND 58202, United States.
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