Developmentally regulated changes in the glycoproteins of the equine embryonic capsule.
Abstract: The embryonic capsule, which covers the equine blastocyst after it loses its zona pellucida, is composed of mucin-like glycoproteins. In the present study, we investigated both macroscopic and molecular changes in the capsule during development. The weight of the capsule increased from day 11-12 of pregnancy and reached a maximum at about day 18, coinciding with the time during which the conceptus migrates extensively throughout the uterus. The sialic acid content of the capsule declined markedly from about day 16, the time of conceptus 'fixation' in the uterus, which suggests a unique developmentally regulated mechanism for the control of embryo mobility. These results lead us to propose that the capsule may have an anti-adhesion function in the developing conceptus, and that this effect could be regulated by the sugar side chains of the capsular glycoproteins. The glycosylation characteristics of the blastocyst coverings also underwent changes at about day 9 of pregnancy, which may be related to loss of the zona pellucida. An anti-capsule monoclonal antibody was raised and shown to recognize a tissue-specific antigen present only on the capsule and trophoblast. This antigen was present on the trophoblastic cells soon after the blastocyst is formed, reached a maximum concentration at about day 18, and was absent after day 22, coinciding with the disappearance of the capsule. Immunohistochemical studies indicate that the mucin-like capsular glycoproteins are secreted, at least in major part, by the trophoblast.(ABSTRACT TRUNCATED AT 250 WORDS)
Publication Date: 1993-11-01 PubMed ID: 8107051DOI: 10.1530/jrf.0.0990653Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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This research explores the development and changes in the equine embryonic capsule, a layer of mucin-like glycoproteins that covers an equine blastocyst. It examines both macroscopic and molecular changes in the capsule during development, with discoveries that could suggest a unique mechanism controlling embryo mobility.
Exploring Developmental Changes in the Embryonic Capsule
- The research focuses on the equine embryonic capsule, a mucin-like glycoprotein covering of an equine blastocyst or early-stage embryo.
- Throughout an equine pregnancy, both large scale (macroscopic) and molecular changes occur in this embryonic capsule. These transitions were the primary focus of the researchers in this study.
Growth and Changes in the Embryonic Capsule
- The research found that the embryonic capsule grew in weight from the 11-12th day of the pregnancy, peaking around the 18th day.
- This growth coincides with extensive migration of the blastocyst or conceptus (an embryo and its adnexa or appendages) throughout the uterus.
Declining Sialic Acid Content and Control of Embryo Mobility
- The researchers found that the sialic acid content of the capsule significantly decreased around day 16, which is the time when the conceptus or embryo becomes ‘fixed’ in a specific location in the uterus.
- This change in the sialic acid content indicates a unique developmentally regulated mechanism controlling embryo mobility within the uterus, potentially mediated by changes in the embryonic capsule itself.
Role and Regulation of Capsular Glycoproteins
- The research suggests that the embryonic capsule may act to prevent adhesion in the developing conceptus.
- The effect could be regulated by sugar side chains present on the glycoproteins that make up the capsule.
- The glycosylation characteristics, the process where sugars are attached to proteins, change at around the 9th day of pregnancy. These changes might be related to the loss of the zona pellucida, a layer that surrounds the oocyte (egg cell) and early-stage embryo.
The Anti-Capsule Monoclonal Antibody
- An anti-capsule monoclonal antibody was developed during the research. The antibody was found to recognize a tissue-specific antigen only present on the capsule and trophoblast (cells forming the outer layer of a blastocyst).
- This antigen was detected on the trophoblastic cells soon after the blastocyst formation, peaking around day 18, and absent after day 22, in line with the disappearance of the capsule.
- The immunohistochemical studies suggested that the capsular glycoproteins are largely secreted by the trophoblast.
Cite This Article
APA
Oriol JG, Sharom FJ, Betteridge KJ.
(1993).
Developmentally regulated changes in the glycoproteins of the equine embryonic capsule.
J Reprod Fertil, 99(2), 653-664.
https://doi.org/10.1530/jrf.0.0990653 Publication
Researcher Affiliations
- Department of Biomedical Sciences, University of Guelph, Ontario, Canada.
MeSH Terms
- Amino Acids / analysis
- Animals
- Blastocyst / metabolism
- Embryo, Mammalian / anatomy & histology
- Embryonic Development
- Female
- Gestational Age
- Glycoproteins / metabolism
- Glycosylation
- Horses / metabolism
- Immunoenzyme Techniques
- N-Acetylneuraminic Acid
- Pregnancy
- Pregnancy, Animal / metabolism
- Sialic Acids / analysis
- Trophoblasts / metabolism
Citations
This article has been cited 10 times.- Klein C, Bruce P, Hammermueller J, Hayes T, Lillie B, Betteridge K. Transcriptional profiling of equine endometrium before, during and after capsule disintegration during normal pregnancy and after oxytocin-induced luteostasis in non-pregnant mares. PLoS One 2021;16(10):e0257161.
- Gibson C, de Ruijter-Villani M, Bauersachs S, Stout TAE. Asynchronous Embryo Transfer Followed by Comparative Transcriptomic Analysis of Conceptus Membranes and Endometrium Identifies Processes Important to the Establishment of Equine Pregnancy. Int J Mol Sci 2020 Apr 7;21(7).
- Klohonatz KM, Coleman SJ, Islas-Trejo AD, Medrano JF, Hess AM, Kalbfleisch T, Thomas MG, Bouma GJ, Bruemmer JE. Coding RNA Sequencing of Equine Endometrium during Maternal Recognition of Pregnancy. Genes (Basel) 2019 Sep 25;10(10).
- Aurich C, Budik S. Early pregnancy in the horse revisited - does exception prove the rule?. J Anim Sci Biotechnol 2015;6:50.
- Tachibana Y, Sakurai T, Bai H, Shiota K, Nambo Y, Nagaoka K, Imakawa K. RNA-seq analysis of equine conceptus transcripts during embryo fixation and capsule disappearance. PLoS One 2014;9(12):e114414.
- Antczak DF, de Mestre AM, Wilsher S, Allen WR. The equine endometrial cup reaction: a fetomaternal signal of significance. Annu Rev Anim Biosci 2013 Jan;1:419-42.
- Suire S, Stewart F, Beauchamp J, Kennedy MW. Uterocalin, a lipocalin provisioning the preattachment equine conceptus: fatty acid and retinol binding properties, and structural characterization. Biochem J 2001 Jun 1;356(Pt 2):369-76.
- Crossett B, Allen WR, Stewart F. A 19 kDa protein secreted by the endometrium of the mare is a novel member of the lipocalin family. Biochem J 1996 Nov 15;320 ( Pt 1)(Pt 1):137-43.
- Lawson EF, Pickford R, Aitken RJ, Gibb Z, Grupen CG, Swegen A. Mapping the lipidomic secretome of the early equine embryo. Front Vet Sci 2024;11:1439550.
- Bazer FW, Johnson GA. Early Embryonic Development in Agriculturally Important Species. Animals (Basel) 2024 Jun 26;14(13).
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