This experiment was designed to identify genes expressed preferentially in the two integuments of the Arabidopsis ovule. Pistils from wild type and two ovule mutants were compared against each aintegumenta-4 (ant-4) which lacks both integuments and inner no outer (ino-1) which lacks the outer integument. Genes that are highly expressed only in the integuments were expected to be reduced in expression in the mutants, as compared with wild type. Pistils containing ovules through all stages of ovule development prior to pollination were pooled for one experiment (FULL arrays), and for two separate experiments, a set of early differentiation stages (EARLY arrays) and a set of later differentiation stages (LATE ARRAYS) were pooled. Wild type and mutant lines are in the ecotype Landsberg erecta.
Expression-based discovery of candidate ovule development regulators through transcriptional profiling of ovule mutants.
None
Specimen part
View SamplesThe ability of an endocrine disruptor exposure during gonadal sex determination to promote a transgenerational prostate disease phenotype was investigated in the current study.
Transgenerational effects of the endocrine disruptor vinclozolin on the prostate transcriptome and adult onset disease.
No sample metadata fields
View SamplesPrimordial follicle assembly is the process by which ovarian primordial follicles are formed. During follicle assembly oocyte nests break down and a layer of pre-granulosa cells surrounds individual oocytes to form primordial follicles. The pool of primordial follicles formed is the source of oocytes for ovulation during a females reproductive life. Complex networks of cellular signaling and gene expression are essential for any biological process. A systems biology experimental approach provides a global view of these gene relationships in a particular developmental process. The current study utilized a systems approach to detect all genes that are differentially expressed in response to seven different growth factor and hormone treatments known to influence primordial follicle assembly in a neonatal rat ovary culture system. One novel growth factor, basic fibroblast growth factor (FGF2), was experimentally determined to inhibit follicle assembly. The different growth factor and hormone treatments were all found to affect the same physiological pathways, but each treatment affected a unique set of differentially expressed genes (signature gene set). A gene bionetwork analysis identified gene modules of coordinately expressed interconnected genes and it was found that different gene modules appear to accomplish distinct tasks during primordial follicle assembly. Unique gene networks were identified for a number of the modules and signature gene sets. Predictions of physiological pathways important to follicle assembly were validated using ovary culture experiments in which ERK1/2 (MAPK1) activity was increased. A number of the highly interconnected genes in these gene networks have previously been linked to primary ovarian insufficiency (POI) and polycystic ovarian disease syndrome (PCOS). Observations have identified novel factors and gene networks that regulate primordial follicle assembly. This systems approach has helped elucidate the molecular control of primordial follicle assembly and provided potential therapeutic targets for the treatment of ovarian disease.
Gene bionetworks that regulate ovarian primordial follicle assembly.
Sex, Specimen part, Treatment
View SamplesEmbryonic exposure to the endocrine disruptor vinclozolin during gonadal sex determination appears to promote an epigenetic reprogramming of the male germ line that is associated with transgenerational adult-onset disease states. Transgenerational effects on the embryonic day 16 (E16) testis demonstrated reproducible changes in the testis transcriptome for multiple generations (F1-F3). The expression of 196 genes was found to be influenced, with the majority of gene expression being decreased or silenced. Dramatic changes in the gene expression of methyltransferases during gonadal sex determination were observed in the F1 and F2 vinclozolin generation (E16) embryonic testis, but the majority returned to control-generation levels by the F3 generation. The most dramatic effects were on the germ-line-associated Dnmt3A and Dnmt3L isoforms. Observations demonstrate that an embryonic exposure to vinclozolin appears to promote an epigenetic reprogramming of the male germ line that correlates with transgenerational alterations in the testis transcriptome in subsequent generations.
Transgenerational epigenetic programming of the embryonic testis transcriptome.
No sample metadata fields
View SamplesNeurotrophins are growth factors that are known to have a role in promoting cell survival and differentiation. The focus of the current study is to examine the role of neurotrophins in regulating ovarian primordial follicle development. Ovaries from 4-day old rats were placed into organ culture and cultured for 10 days in the absence or presence of neurotrophin-3 (NT3), brain-derived neurotrophic factor (BDNF), or nerve growth factor (NGF). Treatment of ovaries with NT3 resulted in a significant (P<0.01) increase in primordial follicle development (i.e. primordial to primary follicle transition). Treatment with BDNF at high doses of 100250 ng/ml also significantly (P<0.01) increased primordial follicle development, but NGF had no effect. Immunohistochemical studies determined that NT3 was present in granulosa cells, interstitial tissue, and in the oocytes of primordial and primary follicles. The NT3 receptor NTRK3 was present in oocytes at all stages of development. Analysis of ovaries that contain predominantly primordial follicles demonstrated the transcripts for NT3, NTRK3, NGF, and the BDNF/neurotrophin-4 (NT4) receptor NTRK2 are expressed, while BDNF, NT4, and the NGF receptor NTRK1 are not detectable. Inhibition of the NTRK3 receptor with the tyrophostin AG 879 resulted in oocyte death and a significant (P<0.01) reduction in follicle pool size. Inhibition of the NTRK receptors with K252a slowed primordial to primary follicle transition. A microarray analysis demonstrated that a small number of genes were differentially expressed after NT3 treatment. Observations indicate that the neurotrophin NT3, acting through the NTRK3 receptor in oocytes, promotes the primordial to primary follicle transition. Reproduction (2009) 138, pp. 697-707
Neurotrophin NT3 promotes ovarian primordial to primary follicle transition.
Sex, Specimen part
View SamplesPrimordial follicle assembly is a process that occurs in the embryonic or early post natal ovary in which oocyte nests break down to form individual primordial follicles. The size of this initial pool of primordial follicles in part determines the reproductive lifespan of the female. Connective tissue growth factor (CTGF) was identified as a potential regulatory candidate for this process in a previous microarray analysis of follicle development. The current study examines the effects of CTGF and associated transforming growth factor beta 1 (TGFbeta-1) on follicle assembly. Ovaries were removed from newborn rat pups and placed in an organ culture system for two days to measure the effect of these factors on follicle assembly. In addition, ovaries were cultured and treated for ten days to determine the potential of CTGF and TGFbeta-1 to manipulate the primordial follicle pool size over a longer developmental time period. The ovaries treated with CTGF for two days were found to have an increased proportion of assembled follicles. TGFbeta-1 had no effect on primordial follicle assembly and in combination with CTGF decreased oocyte number in the ovary after two days of culture. Over ten days of treatment only the combined treatment of CTGF and TGFbeta-1 was found to cause an increase in the proportion of assembled follicles. Interestingly, treatment with TGFbeta-1 alone resulted in fewer total oocytes in the ovary and decreased the primordial follicle pool size after ten days of culture. Observations indicate that CTGF alone or in combination with TGFbeta-1 stimulates primordial follicle assembly and TGFbeta-1 can decrease the primordial follicle pool size. CTGF was found to regulate the ovarian transcriptome during primordial follicle assembly and an integrative network of genes was identified. CTGF is one of the first growth factors shown to promote primordial follicle assembly, while TGFbeta-1 is one of the first factors shown to decrease the primordial follicle pool size. These observations suggest the possibility of manipulating primordial follicle pool size and influencing female reproductive lifespan.
Induction of ovarian primordial follicle assembly by connective tissue growth factor CTGF.
Sex, Specimen part
View SamplesThe oocytes found within the primordial follicles of mammalian ovaries remain quiescent for months to years until they receive the appropriate signals to undergo the primordial to primary follicle transition and initiate folliculogenesis. The molecular mechanisms and extracellular signaling factors that regulate this process remain to be fully elucidated. The current study investigates the mechanisms utilized by anti-Mllerian hormone (AMH; i.e. Mllerian inhibitory substance) to inhibit the primordial to primary follicle transition. Ovaries from 4-day-old rats were placed into organ culture and incubated in the absence or presence of AMH, either alone or in combination with known stimulators of follicle transition, including basic fibroblast growth factor (bFGF), kit ligand (KITL), or keratinocyte growth factor (KGF). Following 10 days of culture, the ovaries were sectioned, stained, and morphologically evaluated to determine the percentage of primordial versus developing follicles. As previously demonstrated, AMH treatment decreased primordial to primary follicle transition. Interestingly, AMH inhibited the stimulatory actions of KITL, bFGF, and KGF. Therefore, AMH can inhibit the basal and stimulated development of primordial follicles. To investigate the mechanism of AMH actions, the influence AMH has on the ovarian transcriptome was analyzed. AMH treatment when compared with controls was found to alter the expression of 707 genes. The overall effect of AMH exposure is to decrease the expression of stimulatory factors, increase the expression of inhibitory factors, and regulate cellular pathways (e.g. transforming growth factor beta signaling pathway) that result in the inhibition of primordial follicle development. Analysis of the regulatory factors and cellular pathways altered by AMH provides a better understanding of the molecular control of primordial follicle development.
Actions of anti-Mullerian hormone on the ovarian transcriptome to inhibit primordial to primary follicle transition.
No sample metadata fields
View SamplesFemale fertility is determined in part by the size and development of the primordial follicle pool. The current study investigates the role of glial cell-line derived neurotrophic factor (GDNF) in the regulation of primordial follicle development in the ovary. Ovaries from four-day old female rat pups were maintained in organ culture for ten days in the absence (control) or presence of GDNF or kit ligand/stem cell factor (KL). Ovaries treated with GDNF contained a significant increase in developing follicles, similar to that observed with KL treatment previously shown to promote follicle development. The actions of GDNF on the ovarian transcriptome were investigated with a microarray analysis. Immunohistochemical studies demonstrated that GDNF is localized to oocyte cytoplasm in follicles of all developmental stages, as well as to cumulus granulosa cells and theca cells in antral follicles. GDNF receptor alpha 1 (GFRalpha1) staining was localized to oocyte cytoplasm of primordial and primary follicles, and at reduced levels in oocytes of antral follicles. GFRalpha1 was present in mural granulosa cells of antral follicles, theca cells, and the ovarian surface epithelium. The localization studies were confirmed with molecular analysis. Microarray analysis was used to identify changes in the ovarian transcriptome and further elucidate the signaling network regulating early follicle development. Observations indicate that GDNF promotes primordial follicle development and mediates autocrine and paracrine cell-cell interactions required during folliculogenesis. In contrast to the testis, ovarian GDNF is predominantly produced by germ cells (oocytes) rather than somatic cells.
Glial-derived neurotrophic factor promotes ovarian primordial follicle development and cell-cell interactions during folliculogenesis.
No sample metadata fields
View SamplesA phylogenetic analysis of seven different species (human, mouse, rat, worm, fly, yeast, and plant) utilizing all (541) basic helix-loop-helix (bHLH) genes identified, including expressed sequence tags (EST), was performed. A super-tree involving six clades and a structural categorization involving the entire coding sequence was established. A nomenclature was developed based on clade distribution to discuss the functional and ancestral relationships of all the genes. The position/location of specific genes on the phylogenetic tree in relation to known bHLH factors allows for predictions of the potential functions of uncharacterized bHLH factors, including EST's. A genomic analysis using microarrays for four different mouse cell types (i.e. Sertoli, Schwann, thymic, and muscle) was performed and considered all known bHLH family members on the microarray for comparison. Cell-specific groups of bHLH genes helped clarify those bHLH genes potentially involved in cell specific differentiation. This phylogenetic and genomic analysis of the bHLH gene family has revealed unique aspects of the evolution and functional relationships of the different genes in the bHLH gene family. PMID: 18557763
Phylogenetic and expression analysis of the basic helix-loop-helix transcription factor gene family: genomic approach to cellular differentiation.
Sex, Specimen part
View SamplesFollicle assembly is the process by which groups or nests of oocytes break down to form primordial follicles. The size of the primordial follicle pool is the major determinant of the reproductive lifespan of a female. Previously, progesterone (P4) has been shown to inhibit follicle assembly, while tumor necrosis factor alpha (TNF-alpha) has been shown to promote the apoptosis that is necessary for follicle assembly. The current study examines how TNF-alpha and progesterone interact to regulate primordial follicle assembly. Ovaries were collected from newborn rats and placed in organ culture to examine the actions of P4 and TNF-alpha. P4 was found to decrease primordial follicle assembly and increase the percentage of un-assembled oocytes both in vitro and in vivo. TNF-alpha treatment did not change the proportion of assembled follicles in cultured ovaries, but did block the ability of P4 to inhibit follicle assembly. Microarray analysis of the ovarian transcriptome revealed that progesterone treatment of the ovaries altered the expression of 513 genes with 132 only expressed after P4 treatment and 16 only expressed in control ovaries. The majority of genes were up-regulated greater than 2-fold over control, with a small subset of 16 genes down-regulated. Categories of genes affected by P4 are described including a group of extra-cellular signaling factors. The progesterone receptors expressed at the time of follicle assembly included the surface membrane progesterone receptors PGRMC1, PGRMC2 and RDA288. The nuclear genomic P4 receptor was not expressed at appreciable levels. Progesterone increased the expression of several genes (TANK, NFkappaB, Bcl2l1 and Bcl2l2) involved in a signaling pathway that promotes cell survival and inhibits apoptosis. Observations indicate that P4 acts through the surface membrane progesterone receptors to regulate primordial follicle assembly, and that TNF-alpha can over-ride the inhibitory actions of P4 on follicle assembly. A major mechanism involved in the actions of P4 is an increase in cell survival genes and inhibition of the apoptosis pathway. Observations provide insight into the hormonal regulation of primordial follicle assembly and lead to novel approaches to potentially manipulate follicle assembly and reproductive capacity.
Interactions between progesterone and tumor necrosis factor-alpha in the regulation of primordial follicle assembly.
No sample metadata fields
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