The Experts below are selected from a list of 252 Experts worldwide ranked by ideXlab platform
Kostas Iatrou - One of the best experts on this subject based on the ideXlab platform.
-
Ecdysteroids and Ecdysteroid Signaling Pathways During Insect Oogenesis
Ecdysone: Structures and Functions, 2020Co-Authors: Luc Swevers, Kostas IatrouAbstract:During insect oogenesis, the oocyte acquires nutrients and genetic determinants to support embryonic development (previtellogenesis and vitellogenesis) and subsequently becomes surrounded by a protective eggshell (Choriogenesis). In many insects, ecdysteroids are synthesized during ovarian growth which is often followed by the accumulation of ecdysteroid conjugates into the eggs. The exact role of the ecdysteroids during oogenesis remains largely unclarified although functions as paracrine or autocrine regulators to signal the progression of follicle development or the resumption of meiosis in the oocyte have been proposed. In the silkmoth, Bombyx mori, although ecdysteroids are synthesized by the ovarian follicles, progression of follicle development towards Choriogenesis requires down-regulation in ecdysteroid signaling. Using the regulation of silkmoth oogenesis by 20-hydroxyecdysone as a starting point, this review discusses the physiological roles of ecdysteroids and the function of the ecdysone regulatory pathway during insect oogenesis.
-
Chorion Genes: A Landscape of Their Evolution, Structure, and Regulation
Annual Review of Entomology, 2014Co-Authors: Argyris Papantonis, Luc Swevers, Kostas IatrouAbstract:Differential regulation at the level of transcription provides a means for controlling gene expression in eukaryotes, especially during development. Insect model systems have been extensively used to decipher the molecular basis of such regulatory cascades, and one of the oldest such model systems is the regulation of chorion gene expression during ovarian follicle maturation. Recent experimental and technological advances have shed new light onto the system, allowing us to revisit it. Thus, in this review we try to summarize almost 40 years' worth of studies on chorion gene regulation while—by comparing Bombyx mori and Drosophila melanogaster models—attempting to present a comprehensive, unified model of the various regulatory aspects of Choriogenesis that takes into account the evolutionary conservation and divergence of the underlying mechanisms.
-
BmVMP90, a large vitelline membrane protein of the domesticated silkmoth Bombyx mori, is an essential component of the developing ovarian follicle
Insect Biochemistry and Molecular Biology, 2012Co-Authors: Nadia Sdralia, Luc Swevers, Kostas IatrouAbstract:We present the characterization of BmVMP90, a vitelline membrane protein (VMP) of the silkmoth Bombyx mori bearing similarities with dipteran VMPs whose existence had recently been suggested by an in silico analysis of the silkmoth genome and follicular cell RNA expression analyses. Using a specific antibody, we determine the presence of BmVMP90 protein in ovarian follicular cell extracts at the end of vitellogenesis and in vitelline membrane extracts but not in the chorion of fractionated eggshells isolated from ovulated follicles. Whole mount follicle immunofluorescence studies reveal a pattern of BmVMP90 deposition matching the «imprinted» pattern of follicular cells on the vitelline membrane surface. Antisense DNA-directed inhibition BmVMP90 expression in ex vivo cultures of early vitellogenic follicles produced a phenotype of kidney- or bean-shaped follicles with detached follicular epithelia, suggestive of the importance of BmVMP90 for the integrity of developing follicles and normal deposition of the chorion structure that follows vitelline membrane formation but no adverse effects on the execution of the follicular cell-imprinted program of Choriogenesis per se.
-
BmCAP, a silkmoth gene encoding multiple protein isoforms characterized by SoHo and SH3 domains: expression analysis during ovarian follicular development.
Insect Biochemistry and Molecular Biology, 2009Co-Authors: Theodoros Georgomanolis, Kostas Iatrou, Luc SweversAbstract:Abstract CAP/ArgBP2/vinexin family proteins, adaptor proteins characterized by three SH3 domains at their C-termini and a SoHo domain towards their N-termini, are known to regulate cell adhesion, cytoskeletal organization, and growth factor signaling. Here we present the isolation and ovarian expression of the BmCAP gene which encodes CAP/ArgBP2/vinexin family proteins in the silkmoth, Bombyx mori . Screening for full-length cDNA clones identified three mRNA isoforms, BmCAP-A1 , BmCAP-A2 and BmCAP-B , which show expression throughout ovarian follicular development. Using an antibody raised against a unique region between the SoHo and SH3 domains, BmCAP-A protein isoforms were identified that show specific expression in different compartments of the ovarian follicles. Immunofluorescence staining of the cells of the follicular epithelium establishes a dynamic pattern of BmCAP-A protein localization during Choriogenesis. During early Choriogenesis, BmCAP-A has a diffuse localization in the cytoplasm but could also be found concentrated at the apical and basal sides at the cell–cell junctions. During late Choriogenesis, the diffuse cytoplasmic staining of BmCAP-A disappears while the staining pattern at the apical side resembles a blueprint for the eggshell surface structure. We suggest that BmCAP-A isoforms have important functions during ovarian development, which involve not only the traditional roles in actin organization or cell–cell adhesion but also the regulation of secretion of chorion proteins and the sculpting of the chorion surface.
-
Prostaglandin signaling and ovarian follicle development in the silkmoth, Bombyx mori.
Insect Biochemistry and Molecular Biology, 2007Co-Authors: Ednildo A. Machado, Luc Swevers, Nadia Sdralia, Marcelo N. Medeiros, Fernando G. De Mello, Kostas IatrouAbstract:Previous work on in vitro culturing of silkmoth (Bombyx mori) ovarian follicles has shown that starting from middle vitellogenesis, follicles develop according to an endogenous developmental program that does not require the presence of extra-ovarian factors. In this paper, we are reporting on our investigation for a possible involvement of autocrine/paracrine signaling by prostaglandins in the control of silkmoth ovarian follicle development. Using an initial rapid test that evaluates the formation of a protective eggshell around the oocyte, we are showing that aspirin and indomethacin, potent inhibitors of prostaglandin biosynthesis, block the transition of cultured vitellogenic follicles into Choriogenesis. More detailed studies involving analyses of temporal expression patterns of genes known to be expressed in follicular epithelium cells at specific stages of ovarian development revealed that inhibition of prostaglandin biosynthesis arrests stages of follicle development from middle vitellogenesis to late Choriogenesis. The arrest could be reversed by the addition of exogenous prostaglandins or cAMP into the culture media leading to the conclusion that the production of prostaglandins triggers cAMP-mediated intracellular signaling that allows the developmental progression of the follicles. Finally, because neither prostaglandins nor cAMP is capable of rescuing a developmental block effected at mid-vitellogenesis by the ecdysone agonist tebufenozide, we are proposing that prostaglandins have a role in the maintenance of normal physiological homeostasis in the ovarian follicles rather than a more specific role in developmental decision-making at distinct stages of follicle development.
Jerome C Regier - One of the best experts on this subject based on the ideXlab platform.
-
Phylogenetics of eggshell morphogenesis in Antheraea (Lepidoptera: Saturniidae): Unique origin and repeated reduction of the aeropyle crown
Systematic Biology, 2005Co-Authors: Jerome C Regier, U. Paukstadt, L.h. Paukstadt, Charles Mitter, Richard S. PeiglerAbstract:Integrated phylogenetic and developmental analyses should enhance our understanding of morphological evolution and thereby improve systematists' ability to utilize morphological characters, but case studies are few. The eggshell (chorion) of Lepidoptera (Insecta) has proven especially tractable experimentally for such analyses because its morphogenesis proceeds by extracellular assembly of proteins. This study focuses on a morphological novelty, the aeropyle crown, that arises at the end of Choriogenesis in the wild silkmoth genus Antheraea. Aeropyle crowns are cylindrical projections, ending in prominent prongs, that surround the openings of breathing tubes (aeropyle channels) traversing the chorion. They occur over the entire egg surface in some species, are localized to a circumferential band in many others, and in some are missing entirely, thus exhibiting variation typical of discrete characters analyzed in morphological phylogenetics. Seeking an integrated developmental-phylogenetic view, we first survey aeropyle crown variation broadly across Antheraea and related genera. We then map these observations onto a robust phylogeny, based on three nuclear genes, to test the adequacy of character codings for aeropyle crown variation and to estimate the frequency and direction of change in those characters. Thirdly, we draw on previous studies of Choriogenesis, supplemented by new data on gene expression, to hypothesize developmental-genetic bases for the inferred chorion character transformations. Aeropyle crowns are inferred to arise just once, in the ancestor of Antheraea, but to undergo four or more subsequent reductions without regain, a pattern consistent with Dollo's Law. Spatial distribution shows an analogous trend, though less clear-cut, toward reduction of coverage by aeropyle crowns. These trends suggest either that there is little or no natural selection on the details of the aeropyle crown structure or that evolution toward functional optima is ongoing, although no direct evidence exists for either. Genetic, biochemical, and microscopy studies point to at least two developmental changes underlying the origin of the aeropyle crown, namely, reinitiation of deposition of chorionic lamellae after the end of normal Choriogenesis (i.e., heterochrony), and sharply increased production of underlying "filler" proteins that push the nascent final lamellae upward to form the crown (i.e., heteroposy). Identification of a unique putative cis-regulatory element shared by unrelated genes involved in aeropyle crown formation suggests a possible simple mechanism for repeated evolutionary reduction and spatial restriction of aeropyle crowns.
-
Choriogenesis in the lepidoptera morphogenesis protein synthesis specific mrna accumulation and primary structure of a chorion cdna from the gypsy moth
Developmental Biology, 1993Co-Authors: Robert F Leclerc, Jerome C RegierAbstract:Abstract Choriogenesis in silkmoths has been used as a model for relating developmental processes and evolutionary change. We now describe parallel studies in a nonsilkmoth lepidopteran species, the gypsy moth. Choriogenesis is described at the levels of ultrastructure, protein composition and synthesis, and specific mRNA accumulation. One complete chorion cDNA sequence is presented and features of its primary structure are discussed. This sequence is shown to be homologous to those of silkmoths.
-
cell specific expression in the silkmoth follicle developmental characterization of a major chorion protein its mrna and gene
Developmental Biology, 1993Co-Authors: Jerome C Regier, Cynthia Cole, Robert F LeclercAbstract:Abstract Choriogenesis (eggshell formation) within the silkmoth Antheraea polyphemus proceeds in parallel for the two major subpopulations of follicle cells, diverging only during the very late period when aeropyle crown surface structures form in one region but not in the other. Correlated with their appearance is the synthesis of a set of region-specific proteins. In this report, aeropyle crowns are physically isolated and their protein composition is shown to consist of those same region-specific proteins. A cDNA clone, called pcvl 16, has been selected and shown to encode a lamellar-forming, aeropyle crown-specific protein, probably of the previously described C3,4 group. These conclusions are based on hybrid-selected translation, Northern analysis, and sequence analysis. pcvl 16 was used to isolate two distinct cloned copies of the 16 gene. Both 16 genes are closely paired with another region-specific gene but the proximity of the two gene pairs to each other is uncertain. Non-region-specific chorion genes expressed at earlier times in Choriogenesis surround the 16 gene pairs, suggesting that cis sequences necessary for regionalized expression may be closely linked to coding sequences. To test this hypothesis, 5′-flanking sequences from eight region-specific genes are compared and shown to share two oligonucletide sequences. One is a known regulatory element found in virtually all moth and fly chorion genes examined. The other, located just upstream from the TATA box, is not found in non-regionally expressed chorion genes and, thus, is a candidate for specifying regional expression.
Robert F Leclerc - One of the best experts on this subject based on the ideXlab platform.
-
Choriogenesis in the lepidoptera morphogenesis protein synthesis specific mrna accumulation and primary structure of a chorion cdna from the gypsy moth
Developmental Biology, 1993Co-Authors: Robert F Leclerc, Jerome C RegierAbstract:Abstract Choriogenesis in silkmoths has been used as a model for relating developmental processes and evolutionary change. We now describe parallel studies in a nonsilkmoth lepidopteran species, the gypsy moth. Choriogenesis is described at the levels of ultrastructure, protein composition and synthesis, and specific mRNA accumulation. One complete chorion cDNA sequence is presented and features of its primary structure are discussed. This sequence is shown to be homologous to those of silkmoths.
-
cell specific expression in the silkmoth follicle developmental characterization of a major chorion protein its mrna and gene
Developmental Biology, 1993Co-Authors: Jerome C Regier, Cynthia Cole, Robert F LeclercAbstract:Abstract Choriogenesis (eggshell formation) within the silkmoth Antheraea polyphemus proceeds in parallel for the two major subpopulations of follicle cells, diverging only during the very late period when aeropyle crown surface structures form in one region but not in the other. Correlated with their appearance is the synthesis of a set of region-specific proteins. In this report, aeropyle crowns are physically isolated and their protein composition is shown to consist of those same region-specific proteins. A cDNA clone, called pcvl 16, has been selected and shown to encode a lamellar-forming, aeropyle crown-specific protein, probably of the previously described C3,4 group. These conclusions are based on hybrid-selected translation, Northern analysis, and sequence analysis. pcvl 16 was used to isolate two distinct cloned copies of the 16 gene. Both 16 genes are closely paired with another region-specific gene but the proximity of the two gene pairs to each other is uncertain. Non-region-specific chorion genes expressed at earlier times in Choriogenesis surround the 16 gene pairs, suggesting that cis sequences necessary for regionalized expression may be closely linked to coding sequences. To test this hypothesis, 5′-flanking sequences from eight region-specific genes are compared and shown to share two oligonucletide sequences. One is a known regulatory element found in virtually all moth and fly chorion genes examined. The other, located just upstream from the TATA box, is not found in non-regionally expressed chorion genes and, thus, is a candidate for specifying regional expression.
Rena Lecanidou - One of the best experts on this subject based on the ideXlab platform.
-
Modeling bidirectional transcription using silkmoth chorion gene promoters.
Organogenesis, 2020Co-Authors: Rena Lecanidou, Argyris PapantonisAbstract:Bidirectional transcription is an interesting feature of eukaryotic genomes; yet not all aspects of its mechanism are understood. Silkmoth Choriogenesis is a model system for studying transcriptional regulation at the initiation level. As chorion genes comprise a large group of divergently transcribed gene pairs, we are presented with the possibility of investigating the intricacies of bidirectional transcription. Τheir well characterized 5’ regulatory regions and expression profiles lay the foundation for investigating protein:protein and protein:DNA interactions, and RNA polymerase function during oocyte development. In this article we summarize current knowledge on chorion gene regulation and propose an approach to modeling bidirectional transcription using chorion promoters.
-
Architectural factor HMGA induces promoter bending and recruits C/EBP and GATA during silkmoth chorion gene regulation
Biochemical Journal, 2008Co-Authors: Argyris Papantonis, Josef Vanden Broeck, Rena LecanidouAbstract:: A protein displaying significant similarity to mammalian HMGA (high-mobility group A) proteins, but also bearing unique structural features, was isolated from silkmoth (Bombyx mori) follicular cells. This factor, named BmHMGA, exhibits specific binding preference for chorion gene promoter elements and induces DNA bending thereon. BmHMGA deploys temporal-specific interaction with transcription factors BmC/EBP (C/EBP is CCAAT/enhancer-binding protein) and BmGATAbeta during follicle maturation. The respective protein complexes can be detected on chorion gene promoters in vivo, with different developmental profiles each time. Analogous interaction takes place on the putative promoter of the BmC/EBP gene, hinting towards a transcriptional circuit that is responsible for the progress of Choriogenesis as a whole. Finally, transient suppression of BmHMGA expression led to down-regulation of chorion genes and the BmC/EBP gene, and revealed recruitment of BmC/EBP, BmGATAbeta and TFIID (transcription factor IID)/TBP (TATA-box-binding protein) by BmHMGA. A revised model for chorion gene regulation is discussed in view of these findings.
-
Chorion gene activation and repression is dependent on BmC/EBP expression and binding to cognate cis-elements.
Biochemical and Biophysical Research Communications, 2008Co-Authors: Argyris Papantonis, S. Sourmeli, Rena LecanidouAbstract:From the different cis-elements clustered on silkmoth chorion gene promoters, C/EBP binding sites predominate. Their sequence composition and dispersal vary amongst promoters of diverse developmental specificity. Occupancy of these sites by BmC/EBP was examined through Southwestern and ChIP assays modified to suit ovarian follicular cells. For the genes studied, binding of BmC/EBP coincided with the respective stages of transcriptional activation. However, the factor was reloaded on promoter sequences long after individual gene repression. Furthermore, suppression of BmC/EBP transcription in developing follicles resulted in de-regulation of chorion gene expression. A biphasic function of BmC/EBP, according to which it may act as both an activator and a repressor during silkmoth Choriogenesis, is considered under the light of the presented data.
-
a novel role for the bombyx slbo homologue bmc ebp in insect Choriogenesis
Biochemical and Biophysical Research Communications, 2005Co-Authors: S. Sourmeli, Argyris Papantonis, Rena LecanidouAbstract:One previously unidentified cDNA clone coding for a C/EBP factor, BmC/EBP, was isolated from Bombyx mori follicular cells. This is the first time that a C/EBP factor has been isolated and characterized in Lepidoptera. We provide information concerning structural features and developmental specificity, as well as in vitro interaction properties with chorion gene promoter modules. BmC/EBP was capable of effectively recognizing homologous binding sites from chorion gene promoters derived from flies and other moths, despite significant diversity of chorion structure, gene organization, and gene expression profiles. We propose that the relative concentration of BmC/EBP, in relation to its differential binding affinity for promoter cis-elements, results in activation or repression of silkmoth chorion gene expression.
-
A novel role for the Bombyx Slbo homologue, BmC/EBP, in insect Choriogenesis.
Biochemical and Biophysical Research Communications, 2005Co-Authors: S. Sourmeli, Argyris Papantonis, Rena LecanidouAbstract:One previously unidentified cDNA clone coding for a C/EBP factor, BmC/EBP, was isolated from Bombyx mori follicular cells. This is the first time that a C/EBP factor has been isolated and characterized in Lepidoptera. We provide information concerning structural features and developmental specificity, as well as in vitro interaction properties with chorion gene promoter modules. BmC/EBP was capable of effectively recognizing homologous binding sites from chorion gene promoters derived from flies and other moths, despite significant diversity of chorion structure, gene organization, and gene expression profiles. We propose that the relative concentration of BmC/EBP, in relation to its differential binding affinity for promoter cis-elements, results in activation or repression of silkmoth chorion gene expression.
Luc Swevers - One of the best experts on this subject based on the ideXlab platform.
-
Ecdysteroids and Ecdysteroid Signaling Pathways During Insect Oogenesis
Ecdysone: Structures and Functions, 2020Co-Authors: Luc Swevers, Kostas IatrouAbstract:During insect oogenesis, the oocyte acquires nutrients and genetic determinants to support embryonic development (previtellogenesis and vitellogenesis) and subsequently becomes surrounded by a protective eggshell (Choriogenesis). In many insects, ecdysteroids are synthesized during ovarian growth which is often followed by the accumulation of ecdysteroid conjugates into the eggs. The exact role of the ecdysteroids during oogenesis remains largely unclarified although functions as paracrine or autocrine regulators to signal the progression of follicle development or the resumption of meiosis in the oocyte have been proposed. In the silkmoth, Bombyx mori, although ecdysteroids are synthesized by the ovarian follicles, progression of follicle development towards Choriogenesis requires down-regulation in ecdysteroid signaling. Using the regulation of silkmoth oogenesis by 20-hydroxyecdysone as a starting point, this review discusses the physiological roles of ecdysteroids and the function of the ecdysone regulatory pathway during insect oogenesis.
-
Chorion Genes: A Landscape of Their Evolution, Structure, and Regulation
Annual Review of Entomology, 2014Co-Authors: Argyris Papantonis, Luc Swevers, Kostas IatrouAbstract:Differential regulation at the level of transcription provides a means for controlling gene expression in eukaryotes, especially during development. Insect model systems have been extensively used to decipher the molecular basis of such regulatory cascades, and one of the oldest such model systems is the regulation of chorion gene expression during ovarian follicle maturation. Recent experimental and technological advances have shed new light onto the system, allowing us to revisit it. Thus, in this review we try to summarize almost 40 years' worth of studies on chorion gene regulation while—by comparing Bombyx mori and Drosophila melanogaster models—attempting to present a comprehensive, unified model of the various regulatory aspects of Choriogenesis that takes into account the evolutionary conservation and divergence of the underlying mechanisms.
-
BmVMP90, a large vitelline membrane protein of the domesticated silkmoth Bombyx mori, is an essential component of the developing ovarian follicle
Insect Biochemistry and Molecular Biology, 2012Co-Authors: Nadia Sdralia, Luc Swevers, Kostas IatrouAbstract:We present the characterization of BmVMP90, a vitelline membrane protein (VMP) of the silkmoth Bombyx mori bearing similarities with dipteran VMPs whose existence had recently been suggested by an in silico analysis of the silkmoth genome and follicular cell RNA expression analyses. Using a specific antibody, we determine the presence of BmVMP90 protein in ovarian follicular cell extracts at the end of vitellogenesis and in vitelline membrane extracts but not in the chorion of fractionated eggshells isolated from ovulated follicles. Whole mount follicle immunofluorescence studies reveal a pattern of BmVMP90 deposition matching the «imprinted» pattern of follicular cells on the vitelline membrane surface. Antisense DNA-directed inhibition BmVMP90 expression in ex vivo cultures of early vitellogenic follicles produced a phenotype of kidney- or bean-shaped follicles with detached follicular epithelia, suggestive of the importance of BmVMP90 for the integrity of developing follicles and normal deposition of the chorion structure that follows vitelline membrane formation but no adverse effects on the execution of the follicular cell-imprinted program of Choriogenesis per se.
-
BmCAP, a silkmoth gene encoding multiple protein isoforms characterized by SoHo and SH3 domains: expression analysis during ovarian follicular development.
Insect Biochemistry and Molecular Biology, 2009Co-Authors: Theodoros Georgomanolis, Kostas Iatrou, Luc SweversAbstract:Abstract CAP/ArgBP2/vinexin family proteins, adaptor proteins characterized by three SH3 domains at their C-termini and a SoHo domain towards their N-termini, are known to regulate cell adhesion, cytoskeletal organization, and growth factor signaling. Here we present the isolation and ovarian expression of the BmCAP gene which encodes CAP/ArgBP2/vinexin family proteins in the silkmoth, Bombyx mori . Screening for full-length cDNA clones identified three mRNA isoforms, BmCAP-A1 , BmCAP-A2 and BmCAP-B , which show expression throughout ovarian follicular development. Using an antibody raised against a unique region between the SoHo and SH3 domains, BmCAP-A protein isoforms were identified that show specific expression in different compartments of the ovarian follicles. Immunofluorescence staining of the cells of the follicular epithelium establishes a dynamic pattern of BmCAP-A protein localization during Choriogenesis. During early Choriogenesis, BmCAP-A has a diffuse localization in the cytoplasm but could also be found concentrated at the apical and basal sides at the cell–cell junctions. During late Choriogenesis, the diffuse cytoplasmic staining of BmCAP-A disappears while the staining pattern at the apical side resembles a blueprint for the eggshell surface structure. We suggest that BmCAP-A isoforms have important functions during ovarian development, which involve not only the traditional roles in actin organization or cell–cell adhesion but also the regulation of secretion of chorion proteins and the sculpting of the chorion surface.
-
Prostaglandin signaling and ovarian follicle development in the silkmoth, Bombyx mori.
Insect Biochemistry and Molecular Biology, 2007Co-Authors: Ednildo A. Machado, Luc Swevers, Nadia Sdralia, Marcelo N. Medeiros, Fernando G. De Mello, Kostas IatrouAbstract:Previous work on in vitro culturing of silkmoth (Bombyx mori) ovarian follicles has shown that starting from middle vitellogenesis, follicles develop according to an endogenous developmental program that does not require the presence of extra-ovarian factors. In this paper, we are reporting on our investigation for a possible involvement of autocrine/paracrine signaling by prostaglandins in the control of silkmoth ovarian follicle development. Using an initial rapid test that evaluates the formation of a protective eggshell around the oocyte, we are showing that aspirin and indomethacin, potent inhibitors of prostaglandin biosynthesis, block the transition of cultured vitellogenic follicles into Choriogenesis. More detailed studies involving analyses of temporal expression patterns of genes known to be expressed in follicular epithelium cells at specific stages of ovarian development revealed that inhibition of prostaglandin biosynthesis arrests stages of follicle development from middle vitellogenesis to late Choriogenesis. The arrest could be reversed by the addition of exogenous prostaglandins or cAMP into the culture media leading to the conclusion that the production of prostaglandins triggers cAMP-mediated intracellular signaling that allows the developmental progression of the follicles. Finally, because neither prostaglandins nor cAMP is capable of rescuing a developmental block effected at mid-vitellogenesis by the ecdysone agonist tebufenozide, we are proposing that prostaglandins have a role in the maintenance of normal physiological homeostasis in the ovarian follicles rather than a more specific role in developmental decision-making at distinct stages of follicle development.