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Vázquez-García E, Villagrán-SantaCruz M. Placentation in the Mexican scincid lizard Plestiodon brevirostris (Squamata: Scincidae). J Morphol 2023; 284:e21563. [PMID: 36719277 DOI: 10.1002/jmor.21563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 01/24/2023] [Accepted: 01/30/2023] [Indexed: 02/01/2023]
Abstract
Viviparity is the reproductive pattern in which females gestate eggs within their reproductive tract to complete their development and give birth to live offspring. Within extant sauropsids, only the Squamata (e.g., snakes, lizards, and amphisbaenians) evolved viviparity, representing 20% of the existing species. The genus Plestiodon is represented by 43 species and is one of the most widely distributed genera of the Scincidae in Mexico. The goal of this research has been to determine the placental morphology and ontogeny during gestation in the lizard Plestiodon brevirostris. Specimens were dissected to obtain the embryonic chambers and the embryos were categorized to carry out the correlation between the development stage and the placenta development. The embryonic chambers were processed using the conventional histological technique for light microscopy. The identified embryonic stages were 4, 29, 34, 36, and 39. A thin eggshell surrounds the egg in early developmental stages; however, this structure is already absent in the embryonic hemisphere during the developmental stage 29. The results revealed that P. brevirostris is a lecithotrophic species, but a close maternal-fetal relationship is established by tissue apposition. Ontogenically, the placental types that form in the embryonic hemisphere are the chorioplacenta, choriovitelline placenta, and chorioallantoic placenta; whereas the omphaloplacenta is formed in the abembryonic hemisphere. The structure of the chorioallantoic placenta in P. brevirostris suggests that it may play a role during gas exchange between the mother and the embryo, due to the characteristics of the epithelia that comprise it. The structure of embryonic and maternal epithelia of the omphaloplacenta suggests a role in the absorption of the eggshell during gestation and possibly in the transport or diffusion of some nutrients. In general, it is evident that ontogeny and placental characteristics of P. brevirostris match those of other species of viviparous lecithotrophic scincids.
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Affiliation(s)
- Erwin Vázquez-García
- Departamento de Biología Comparada, Laboratorio de Biología Tisular y Reproductora, Facultad de Ciencias, Universidad Nacional Autónoma de México, México City, Mexico
| | - Maricela Villagrán-SantaCruz
- Departamento de Biología Comparada, Laboratorio de Biología Tisular y Reproductora, Facultad de Ciencias, Universidad Nacional Autónoma de México, México City, Mexico
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Nekliudova UA, Schwaha TF, Kotenko ON, Gruber D, Cyran N, Ostrovsky AN. Three in one: evolution of viviparity, coenocytic placenta and polyembryony in cyclostome bryozoans. BMC Ecol Evol 2021; 21:54. [PMID: 33845757 PMCID: PMC8042935 DOI: 10.1186/s12862-021-01775-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 03/08/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Placentation has evolved multiple times among both chordates and invertebrates. Although they are structurally less complex, invertebrate placentae are much more diverse in their origin, development and position. Aquatic colonial suspension-feeders from the phylum Bryozoa acquired placental analogues multiple times, representing an outstanding example of their structural diversity and evolution. Among them, the clade Cyclostomata is the only one in which placentation is associated with viviparity and polyembryony-a unique combination not present in any other invertebrate group. RESULTS The histological and ultrastructural study of the sexual polymorphic zooids (gonozooids) in two cyclostome species, Crisia eburnea and Crisiella producta, revealed embryos embedded in a placental analogue (nutritive tissue) with a unique structure-comprising coenocytes and solitary cells-previously unknown in animals. Coenocytes originate via nuclear multiplication and cytoplasmic growth among the cells surrounding the early embryo. This process also affects cells of the membranous sac, which initially serves as a hydrostatic system but later becomes main part of the placenta. The nutritive tissue is both highly dynamic, permanently rearranging its structure, and highly integrated with its coenocytic 'elements' being interconnected via cytoplasmic bridges and various cell contacts. This tissue shows evidence of both nutrient synthesis and transport (bidirectional transcytosis), supporting the enclosed multiple progeny. Growing primary embryo produces secondary embryos (via fission) that develop into larvae; both the secondary embyos and larvae show signs of endocytosis. Interzooidal communication pores are occupied by 1‒2 specialized pore-cells probably involved in the transport of nutrients between zooids. CONCLUSIONS Cyclostome nutritive tissue is currently the only known example of a coenocytic placental analogue, although syncytial 'elements' could potentially be formed in them too. Structurally and functionally (but not developmentally) the nutritive tissue can be compared with the syncytial placental analogues of certain invertebrates and chordates. Evolution of the cyclostome placenta, involving transformation of the hydrostatic apparatus (membranous sac) and change of its function to embryonic nourishment, is an example of exaptation that is rather widespread among matrotrophic bryozoans. We speculate that the acquisition of a highly advanced placenta providing massive nourishment might support the evolution of polyembryony in cyclostomes. In turn, massive and continuous embryonic production led to the evolution of enlarged incubating polymorphic gonozooids hosting multiple progeny.
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Affiliation(s)
- U A Nekliudova
- Department of Evolutionary Biology, Integrative Zoology, Faculty of Life Sciences, University of Vienna, Althanstr. 14, 1090, Vienna, Austria
- Department of Invertebrate Zoology, Faculty of Biology, Saint Petersburg State University, Universitetskaja nab. 7/9, 199034, Saint Petersburg, Russia
| | - T F Schwaha
- Department of Evolutionary Biology, Integrative Zoology, Faculty of Life Sciences, University of Vienna, Althanstr. 14, 1090, Vienna, Austria
| | - O N Kotenko
- Department of Invertebrate Zoology, Faculty of Biology, Saint Petersburg State University, Universitetskaja nab. 7/9, 199034, Saint Petersburg, Russia
| | - D Gruber
- Core Facility Cell Imaging and Ultrastructure Research, Faculty of Life Sciences, University of Vienna, Althanstr. 14, 1090, Vienna, Austria
| | - N Cyran
- Core Facility Cell Imaging and Ultrastructure Research, Faculty of Life Sciences, University of Vienna, Althanstr. 14, 1090, Vienna, Austria
| | - A N Ostrovsky
- Department of Invertebrate Zoology, Faculty of Biology, Saint Petersburg State University, Universitetskaja nab. 7/9, 199034, Saint Petersburg, Russia.
- Department of Palaeontology, Faculty of Earth Sciences, Geography and Astronomy, University of Vienna, Althanstr. 14, 1090, Vienna, Austria.
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Hernández-Díaz N, Leal F, Ramírez-Pinilla MP. Parallel evolution of placental calcium transfer in the lizard Mabuya and eutherian mammals. J Exp Biol 2021; 224:jeb.237891. [PMID: 33568441 DOI: 10.1242/jeb.237891] [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: 09/18/2020] [Accepted: 02/01/2021] [Indexed: 12/28/2022]
Abstract
An exceptional case of parallel evolution between lizards and eutherian mammals occurs in the evolution of viviparity. In the lizard genus Mabuya, viviparity provided the environment for the evolution of yolk-reduced eggs and obligate placentotrophy. One major event that favored the evolution of placentation was the reduction of the eggshell. As with all oviparous reptiles, lizard embryos obtain calcium from both the eggshell and egg yolk. Therefore, the loss of the eggshell likely imposes a constraint for the conservation of the egg yolk, which can only be obviated by the evolution of alternative mechanisms for the transport of calcium directly from the mother. The molecular and cellular mechanisms employed to solve these constraints, in a lizard with only a rudimentary eggshell such as Mabuya, are poorly understood. Here, we used RT-qPCR on placental and uterine samples during different stages of gestation in Mabuya, and demonstrate that transcripts of the calcium transporters trpv6, cabp28k, cabp9k and pmca are expressed and gradually increase in abundance through pregnancy stages, reaching their maximum expression when bone mineralization occurs. Furthermore, CABP28K/9K proteins were studied by immunofluorescence, demonstrating expression in specific regions of the mature placenta. Our results indicate that the machinery for calcium transportation in the Mabuya placenta was co-opted from other tissues elsewhere in the vertebrate bodyplan. Thus, the calcium transportation machinery in the placenta of Mabuya evolved in parallel with the mammalian placenta by redeploying the expression of similar calcium transporter genes.
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Affiliation(s)
- Nathaly Hernández-Díaz
- Grupo de Estudios en Biodiversidad, Escuela de Biología, Facultad de Ciencias, Universidad Industrial de Santander, Bucaramanga, Santander, Colombia
| | - Francisca Leal
- Grupo de Estudios en Biodiversidad, Escuela de Biología, Facultad de Ciencias, Universidad Industrial de Santander, Bucaramanga, Santander, Colombia
| | - Martha Patricia Ramírez-Pinilla
- Grupo de Estudios en Biodiversidad, Escuela de Biología, Facultad de Ciencias, Universidad Industrial de Santander, Bucaramanga, Santander, Colombia
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Blackburn DG, Stewart JR. Morphological research on amniote eggs and embryos: An introduction and historical retrospective. J Morphol 2021; 282:1024-1046. [PMID: 33393149 DOI: 10.1002/jmor.21320] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Revised: 12/31/2020] [Accepted: 01/01/2021] [Indexed: 12/21/2022]
Abstract
Evolution of the terrestrial egg of amniotes (reptiles, birds, and mammals) is often considered to be one of the most significant events in vertebrate history. Presence of an eggshell, fetal membranes, and a sizeable yolk allowed this egg to develop on land and hatch out well-developed, terrestrial offspring. For centuries, morphologically-based studies have provided valuable information about the eggs of amniotes and the embryos that develop from them. This review explores the history of such investigations, as a contribution to this special issue of Journal of Morphology, titled Developmental Morphology and Evolution of Amniote Eggs and Embryos. Anatomically-based investigations are surveyed from the ancient Greeks through the Scientific Revolution, followed by the 19th and early 20th centuries, with a focus on major findings of historical figures who have contributed significantly to our knowledge. Recent research on various aspects of amniote eggs is summarized, including gastrulation, egg shape and eggshell morphology, eggs of Mesozoic dinosaurs, sauropsid yolk sacs, squamate placentation, embryogenesis, and the phylotypic phase of embryonic development. As documented in this review, studies on amniote eggs and embryos have relied heavily on morphological approaches in order to answer functional and evolutionary questions.
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Affiliation(s)
- Daniel G Blackburn
- Department of Biology and Electron Microscopy Center, Trinity College, Hartford, Connecticut, USA
| | - James R Stewart
- Department of Biological Sciences, East Tennessee State University, Johnson City, Tennessee, USA
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History of reptile placentology, part III: Giacomini’s 1891 histological monograph on lizard placentation. Placenta 2017; 60:93-99. [DOI: 10.1016/j.placenta.2017.10.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Revised: 10/22/2017] [Accepted: 10/30/2017] [Indexed: 12/30/2022]
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An endogenous retroviral envelope syncytin and its cognate receptor identified in the viviparous placental Mabuya lizard. Proc Natl Acad Sci U S A 2017; 114:E10991-E11000. [PMID: 29162694 DOI: 10.1073/pnas.1714590114] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Syncytins are envelope genes from endogenous retroviruses that have been captured during evolution for a function in placentation. They have been found in all placental mammals in which they have been searched, including marsupials. Placental structures are not restricted to mammals but also emerged in some other vertebrates, most frequently in lizards, such as the viviparous Mabuya Scincidae. Here, we performed high-throughput RNA sequencing of a Mabuya placenta transcriptome and screened for the presence of retroviral env genes with a full-length ORF. We identified one such gene, which we named "syncytin-Mab1," that has all the characteristics expected for a syncytin gene. It encodes a membrane-bound envelope protein with fusogenic activity ex vivo, is expressed at the placental level as revealed by in situ hybridization and immunohistochemistry, and is conserved in all Mabuya species tested, spanning over 25 My of evolution. Its cognate receptor, required for its fusogenic activity, was searched for by a screening assay using the GeneBridge4 human/Chinese hamster radiation hybrid panel and found to be the MPZL1 gene, previously identified in mammals as a signal-transducing transmembrane protein involved in cell migration. Together, these results show that syncytin capture is not restricted to placental mammals, but can also take place in the rare nonmammalian vertebrates in which a viviparous placentotrophic mode of reproduction emerged. It suggests that similar molecular tools have been used for the convergent evolution of placentation in independently evolved and highly distant vertebrates.
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Blackburn DG, Anderson KE, Lo AR, Marquez EC, Callard IP. Placentation in watersnakes II: Placental ultrastructure in N
erodia erythrogaster
(Colubridae: Natricinae). J Morphol 2017; 278:675-688. [DOI: 10.1002/jmor.20662] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2016] [Revised: 01/05/2017] [Accepted: 01/11/2017] [Indexed: 01/17/2023]
Affiliation(s)
- Daniel G. Blackburn
- Department of Biology, and Electron Microscopy Facility; Trinity College; Hartford Connecticut 06106
| | - Kristie E. Anderson
- Department of Biology, and Electron Microscopy Facility; Trinity College; Hartford Connecticut 06106
| | - Amy R. Lo
- Department of Biology, and Electron Microscopy Facility; Trinity College; Hartford Connecticut 06106
| | - Emily C. Marquez
- Department of Biology; Boston University; Boston Massachusetts 02215
| | - Ian P. Callard
- Department of Biology; Boston University; Boston Massachusetts 02215
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Blackburn DG, Starck JM. Morphological specializations for fetal maintenance in viviparous vertebrates: An introduction and historical retrospective. J Morphol 2015; 276:E1-16. [DOI: 10.1002/jmor.20410] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2015] [Accepted: 05/11/2015] [Indexed: 12/18/2022]
Affiliation(s)
- Daniel G. Blackburn
- Department of Biology; and Electron Microscopy Center; Trinity College; Hartford Connecticut 06106
| | - J. Matthias Starck
- Department of Biology; University of Munich; D-82152 Planegg-Martinsried Germany
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Blackburn DG. Viviparous placentotrophy in reptiles and the parent-offspring conflict. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2015; 324:532-48. [DOI: 10.1002/jez.b.22624] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 03/10/2015] [Indexed: 12/29/2022]
Affiliation(s)
- Daniel G. Blackburn
- Departmentof Biology; Electron Microscopy Center; Trinity College; Hartford Connecticut
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Blackburn DG. Evolution of viviparity in squamate reptiles: Reversibility reconsidered. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2015; 324:473-86. [DOI: 10.1002/jez.b.22625] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 03/20/2015] [Indexed: 11/10/2022]
Affiliation(s)
- Daniel G. Blackburn
- Department of Biology, Electron Microscopy Center; Trinity College; Hartford Connecticut
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11
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Griffith OW, Blackburn DG, Brandley MC, Van Dyke JU, Whittington CM, Thompson MB. Ancestral state reconstructions require biological evidence to test evolutionary hypotheses: A case study examining the evolution of reproductive mode in squamate reptiles. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2015; 324:493-503. [DOI: 10.1002/jez.b.22614] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 01/18/2015] [Indexed: 12/27/2022]
Affiliation(s)
- Oliver W. Griffith
- School of Biological Sciences; Heydon Laurence Building (A08); University of Sydney; Camperdown NSW Australia
| | | | - Matthew C. Brandley
- School of Biological Sciences; Heydon Laurence Building (A08); University of Sydney; Camperdown NSW Australia
| | - James U. Van Dyke
- School of Biological Sciences; Heydon Laurence Building (A08); University of Sydney; Camperdown NSW Australia
| | - Camilla M. Whittington
- School of Biological Sciences; Heydon Laurence Building (A08); University of Sydney; Camperdown NSW Australia
| | - Michael B. Thompson
- School of Biological Sciences; Heydon Laurence Building (A08); University of Sydney; Camperdown NSW Australia
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12
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Blackburn DG. Evolution of vertebrate viviparity and specializations for fetal nutrition: A quantitative and qualitative analysis. J Morphol 2014; 276:961-90. [DOI: 10.1002/jmor.20272] [Citation(s) in RCA: 184] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 01/27/2014] [Accepted: 02/09/2014] [Indexed: 01/21/2023]
Affiliation(s)
- Daniel G. Blackburn
- Department of Biology and; Electron Microscopy Center, Trinity College; Hartford Connecticut 06106
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Itonaga K, Wapstra E, Jones SM. A novel pattern of placental leucine transfer during mid to late gestation in a highly placentotrophic viviparous lizard. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2012; 318:308-15. [PMID: 22821866 DOI: 10.1002/jez.b.22446] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Placentotrophy is the nourishment of embryos by resources provided via the placenta during gestation. The magnitude and timing of placental nutrient support during pregnancy are important for embryonic growth, especially in highly placentotrophic animals such as mammals. However, no study has yet investigated how placental organic nutrient support may change during pregnancy in highly placentotrophic viviparous reptiles. Amino acids are essential nutrients for embryonic growth and leucine is a common amino acid. The magnitude and timing of placental leucine transfer may affect embryonic growth and mass and, therefore, offspring phenotype. In this study, female Pseudemoia entrecasteauxii, a highly placentotrophic viviparous skink, were collected throughout gestation. We injected (3)H-leucine into these gravid females and assessed the transfer of (3)H-leucine into maternal compartments (i.e., the blood and the liver), and into embryonic compartments (i.e., the embryo, the yolk, and the amniotic fluid). At either 60 or 120 min post-injection, the radioactivity in each sample was extracted and then counted, and the transfer ratio was calculated. Our results provide direct evidence that circulating maternal leucine passes through the placenta into the embryos in this species. The relative rate of placental leucine transfer did not alter during mid to late gestation. This suggests the steady somatic growth of the embryos during mid-late pregnancy is dependent upon the placental transfer of nutrients rather than yolk stores. This pattern of placental nutrient support may determine offspring body size at birth and, therefore, offspring fitness in P. entrecasteauxii.
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Affiliation(s)
- Keisuke Itonaga
- School of Zoology, University of Tasmania, Hobart, Tasmania, Australia
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BIAZIK JOANNAM, PARKER SCOTTL, MURPHY CHRISTOPHERR, THOMPSON MICHAELB. Uterine Epithelial Morphology and Progesterone Receptors in a Mifepristone-treated Viviparous LizardPseudemoia entrecasteauxii(Squamata: Scincidae) During Gestation. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2012; 318:148-58. [DOI: 10.1002/jez.b.22003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- JOANNA M. BIAZIK
- School of Biological Sciences; University of Sydney; Sydney; Australia
| | - SCOTT L. PARKER
- School of Biological Sciences; University of Sydney; Sydney; Australia
| | - CHRISTOPHER R. MURPHY
- Discipline of Anatomy and Histology; School of Medical Science and Bosch Institute; University of Sydney; Sydney; Australia
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Brandley MC, Young RL, Warren DL, Thompson MB, Wagner GP. Uterine gene expression in the live-bearing lizard, Chalcides ocellatus, reveals convergence of squamate reptile and mammalian pregnancy mechanisms. Genome Biol Evol 2012; 4:394-411. [PMID: 22333490 PMCID: PMC3318437 DOI: 10.1093/gbe/evs013] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/03/2012] [Indexed: 12/18/2022] Open
Abstract
Although the morphological and physiological changes involved in pregnancy in live-bearing reptiles are well studied, the genetic mechanisms that underlie these changes are not known. We used the viviparous African Ocellated Skink, Chalcides ocellatus, as a model to identify a near complete gene expression profile associated with pregnancy using RNA-Seq analyses of uterine transcriptomes. Pregnancy in C. ocellatus is associated with upregulation of uterine genes involved with metabolism, cell proliferation and death, and cellular transport. Moreover, there are clear parallels between the genetic processes associated with pregnancy in mammals and Chalcides in expression of genes related to tissue remodeling, angiogenesis, immune system regulation, and nutrient provisioning to the embryo. In particular, the pregnant uterine transcriptome is dominated by expression of proteolytic enzymes that we speculate are involved both with remodeling the chorioallantoic placenta and histotrophy in the omphaloplacenta. Elements of the maternal innate immune system are downregulated in the pregnant uterus, indicating a potential mechanism to avoid rejection of the embryo. We found a downregulation of major histocompatability complex loci and estrogen and progesterone receptors in the pregnant uterus. This pattern is similar to mammals but cannot be explained by the mammalian model. The latter finding provides evidence that pregnancy is controlled by different endocrinological mechanisms in mammals and reptiles. Finally, 88% of the identified genes are expressed in both the pregnant and the nonpregnant uterus, and thus, morphological and physiological changes associated with C. ocellatus pregnancy are likely a result of regulation of genes continually expressed in the uterus rather than the initiation of expression of unique genes.
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Stinnett HK, Stewart JR, Ecay TW, Pyles RA, Herbert JF, Thompson MB. Placental development and expression of calcium transporting proteins in the extraembryonic membranes of a placentotrophic lizard. J Morphol 2011; 273:347-59. [DOI: 10.1002/jmor.11030] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Revised: 09/14/2011] [Accepted: 09/18/2011] [Indexed: 11/09/2022]
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Blackburn DG, Flemming AF. Invasive implantation and intimate placental associations in a placentotrophic african lizard, Trachylepis ivensi (scincidae). J Morphol 2011; 273:137-59. [DOI: 10.1002/jmor.11011] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Revised: 07/14/2011] [Accepted: 07/18/2011] [Indexed: 11/09/2022]
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Transplacental nutrient transfer during gestation in the Andean lizard Mabuya sp. (Squamata, Scincidae). J Comp Physiol B 2010; 181:249-68. [DOI: 10.1007/s00360-010-0514-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2010] [Revised: 08/16/2010] [Accepted: 09/07/2010] [Indexed: 11/26/2022]
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Biazik JM, Thompson MB, Murphy CR. Desmosomes in the uterine epithelium of noninvasive skink placentae. Anat Rec (Hoboken) 2010; 293:502-12. [PMID: 20169564 DOI: 10.1002/ar.21093] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Australian species of viviparous skinks have noninvasive epitheliochorial placentation where there is no breeching or interruption of the uterine epithelial cell barrier. This is contrary to some African and South American species of skinks which exhibit invading chorionic cells and a localized endotheliochorial placenta. The desmosomes, which maintain the adhesive properties of the junctional complex between uterine epithelial cells, were found to decrease as gestation progressed in the uterus of two highly placentotrophic Australian skinks, but no changes in desmosomal numbers were present in the uterus of two Australian oviparous skinks or viviparous skinks with a simple placenta. In mammals, desmosomes decrease in the uterine epithelium of species with invasive hemochorial placentation, where less chemical and mechanical adhesion between cells assists the invading trophoblast at the time of implantation. However, Australian viviparous skinks do not have an invasive trophoblast; yet, similarities in decreasing lateral cellular adhesion exist in the uterus of both invasive and noninvasive placental types. This similarity in cellular mechanisms suggests a conservation of plasma membrane changes across placentation irrespective of reptilian or mammalian origin.
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Affiliation(s)
- Joanna M Biazik
- Bosch Institute, The University of Sydney, New South Wales, Australia.
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Blackburn DG, Flemming AF. Morphology, development, and evolution of fetal membranes and placentation in squamate reptiles. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2009; 312:579-89. [DOI: 10.1002/jez.b.21234] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Leal F, Ramírez-Pinilla MP. Morphological Variation in the Allantoplacenta Within the GenusMabuya(Squamata: Scincidae). Anat Rec (Hoboken) 2008; 291:1124-39. [DOI: 10.1002/ar.20733] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Vieira S, de Perez G, Ramírez-Pinilla MP. Invasive Cells in the Placentome of Andean Populations ofMabuya: An Endotheliochorial Contribution to the Placenta? Anat Rec (Hoboken) 2007; 290:1508-18. [DOI: 10.1002/ar.20609] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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