1,721,119 research outputs found
Role of Progesterone Receptor Membrane : Component 1in oogenesis and mammalian fertility
No full textInfertility is a major problem affecting domestic mammals and declining fertility is damaging the profitability of dairy farms in Europe and worldwide. Since declining fertility in cattle is largely due to the poor quality of oocytes, research on the factors that affect oocyte quality is essential. Based on our preliminary data, we propose that Progesterone Receptor Membrane Component 1 (PGRMC1) is one of the key factors that regulate mammalian oocyte quality
Progesterone and Progesterone Receptor Membrane Component 1 regulate microtubules stability during mitosis of normal and cancerous ovarian cancer cells
No full textA Novel Role for Progesterone Receptor Membrane Component 1 in Regulating Microtubule Dynamics During Rat Granulosa Cells Mitosis
No full textA novel role for progesterone and progesterone receptor membrane component 1 in regulating spindle microtubule stability during rat and human ovarian cell mitosis
No full textThe present studies were designed to assess the roles of progesterone (P4) and Progesterone Receptor Membrane Component 1 (PGRMC1) in regulating mitosis of spontaneously immortalized granulosa cells (SIGCs) and ovarian cancer cells, SKOV-3 cells. Because PGRMC1 has been detected among the proteins of the human mitotic spindle, we theorized that P4 and PGRMC1 could affect mitosis through a microtubule-dependent process. The present study confirms that SIGC growth is slowed by either P4 treatment or transfection of a PGRMC1 antibody. In both cases, slower cell proliferation was accompanied by an increased percentage of mitotic cells, which is consistent with a P4-induced prolongation of the M phase of the cell cycle. In addition, P4 increased the stability of the spindle microtubules, as assessed by the rate of beta-tubulin disassembly in response to cooling. Also, P4 increased spindle microtubule stability of SKOV-3 cells. This effect was mimicked by the depletion of PGRMC1 in these cells. Importantly, P4 did not increase the stability of the microtubules over that observed in PGRMC1-depleted SKOV-3 cells. Immunofluorescent analysis revealed that PGRMC1 is distributed to the spindle apparatus as well as to the centrosomes at metaphase. Further in situ proximity ligation assay revealed that PGRMC1 interacted with beta-tubulin. Taken together, these results suggest that P4 inhibits mitosis of ovarian cells by increasing the stability of the mitotic spindle. Moreover, P4's actions appear to be dependent on PGRMC1's function within the mitotic spindle
Caratterizzazione dei meccanismi che regolano l'acquisizione della competenza allo sviluppo in vitro dell'ovocita nei mammiferi domestici : dottorato di ricerca in biotecnologie applicate alle scienze veterinarie e zootecniche : tesi di dottorato di ricerca
No full textCharacterization of the mechanisms involved in the acquisition of in vitro developmental competence in mammalian oocytes The female gamete acquires the capability to become an embryo after fertilization during folliculogenesis, when oocyte and somatic cells communicate by paracrine and junctional mechanisms, through a series of molecular events not yet well understood that modify both nuclear and cytoplasmic compartments. The purpose of this study was to clarify some of these events by studying the modifications of chromatin organization within the nucleus of immature bovine oocyte. Following fluorescence nuclear staining we found that the nuclear architecture undergoes dynamic changes during the final oocyte growth phase in which chromatin becomes progressively condensed. Furthermore we found that oocytes with a higher degree of chromatin condensation were characterized by a higher embryonic developmental capability after fertilization. Successively, ultrastructural studies of the nuclear and cytoplasmic compartments revealed that the process of chromatin reorganization could be related to profound key structural modifications, like nucleolar inactivation and remodeling of specific ooplasmic structures that take place during the later phases of oocyte growth. Furthermore, we investigate on the possible role of gap junction mediated communication between oocytes and surrounding cumulus cells in modulating changes of chromatin structure. As an increase of chromatin condensation corresponded to a higher incidence of communication interruption we concluded that this functional coupling could be implicated in large-scale chromatin remodeling process
Evidence for a genomic mechanism of action for progesterone receptor membrane component-1
No full textProgesterone receptor membrane component 1 (PGRMC1) is highly expressed in the granulosa and luteal cells of rodent and primate ovaries. Interestingly, its molecular weight as assessed by Western blot is dependent on its cellular localization with a ≈27 kDa form being detected in the cytoplasm and higher molecular weight forms being detected in the nucleus. The higher molecular weight forms of PGRMC1 are sumoylated suggesting that they are involved in regulating gene transcription, since sumoylation of nuclear proteins often is associated with regulation of transcriptional activity of the sumoylated protein. In order to identify a set of candidate genes that are regulated by PGRMC1, a human granulosa/luteal cell line (hGL5 cells) was treated with PGRMC1 siRNA and changes in gene expression monitored by microarray analysis. The microarray analysis revealed that PGRMC1 generally functioned as a repressor of transcription, since depletion of PGRMC1 resulted in a disproportionate increase in the number of transcripts. Moreover, a pathway analysis implicated PGRMC1 in the regulation of apoptosis, which is consistent with PGRMC1's known biological action. More importantly these results support the concept that PGRMC1 influences gene transcription. Additional studies reveal that progesterone (P4) acting through a PGRMC1-dependent mechanism suppresses the activity of the transcription factor, Tcf/Lef, thereby identifying one molecular pathway through which P4-PGRMC1 can regulate gene transcription and ultimately apoptosis
Changes of Large-Scale Chromatin Configuration During Mammalian Oocyte Differentiation
No full textMammalian oocyte development is characterized by impressive dynamic changes in chromatin structure and function within the germinal vesicle (GV). During meiotic arrest at diplotene stage, and particularly during the oocyte growth phase leading to the formation of the fully-grown and dif- ferentiated oocyte, the chromatin enclosed within the GV is subjected to several levels of regulation controlling both its structure and function. Morphologically, the chromosomes lose their individuality and form a loose chromatin mass, which in turn undergoes profound and dynamic rearrangements within the GV before the meiotic resumption. These large- scale chromatin configuration changes have been studied in several mam- mals and progressive condensation of the chromatin has been related to the achievement of meiotic and developmental potential. In this chapter we will give an overview of the scientific literature on this topic, highlight- ing how changes in chromatin configurations are related to both functional and structural modifications occurring in the oocyte nuclear and cytoplas- mic compartments. Further, we will discuss the machinery regulating this complex process, including the fundamental role exerted by the follicular cells also throughout intracellular messenger dependent mechanism(s). Finally, we will discuss possible implications for the field of assisted reproductive technologies
Progesterone regulation of progesterone receptor membrane component 1 (PGRMC1) sumoylation and transcriptional activity in spontaneously immortalized granulosa cells
No full textProgesterone (P4) receptor membrane component (PGRMC)1 is detected as a 22-kDa band as well as higher molecular mass bands (>50 kDa) in spontaneously immortalized granulosa cells. That these higher molecular mass bands represent PGRMC1 is supported by the findings that they are not detected when either the primary antibody is omitted or the PGRMC1 antibody is preabsorbed with recombinant PGRMC1. Some but not most of the higher molecular mass bands are due to oligomerization. At least one of the higher molecular mass bands is sumoylated, because PGRMC1 coimmunoprecipitates with small ubiquitin-like modifier protein-1. Moreover, in situ proximity ligation assays reveal a direct interaction between PGRMC1 and small ubiquitin-like modifier protein-1. This interaction is increased by P4. Finally, the higher molecular mass forms of PGRMC1 localize to the nucleus. An analysis of transcription factor activity demonstrates that P4 suppresses T-cell factor/lymphoid enhancer factor (Tcf/Lef) activity through a PGRMC1-dependent mechanism, because treatment with PGRMC1 small interfering RNA depletes PGRMC1 levels and attenuates P4's effects on Tcf/Lef activity. In addition, transfection of a PGRMC1-Flag fusion protein enhances basal Tcf/Lef activity, which is suppressed by P4 treatment. Conversely, transfection of a PGRMC1-Flag protein in which all the sumoylation sites are mutated increases basal Tcf/Lef activity but attenuates P4's ability to suppress Tcf/Lef activity. Therefore, the ability to suppress Tcf/Lef activity is likely an essential part of the mechanism through which P4 activation of PGRMC1 regulates the gene cascades that control granulosa cell function with this action being dependent in part on the sumoylation status of PGRMC1
On the chromatin of the immature oocyte : from morphology to function and regulatory mechanisms mediated by follicular cells
Full text linkIn her comment entitled ‘Nuclear histochemistry: its history in fifty volumes’ (Eur J Histochem 2006; 50:79-81) Maria Gabriella Manfredi Romanini referred to “nuclear histochemistry” as a “real molecular biology in situ, applied to research on dynamic processes in the nucleus, which makes the microscopic and histo- chemical approach absolutely irreplaceable for the progress of our understanding of cell biology”. These words perfectly exemplify the research path that is elucidating the process of remodeling of chromatin configuration within the nucleus of the mammalian oocyte. This process, which occurs towards the end of the oocyte differentiation phase before meiotic resumption, has received much attention in the last decade since it has a tremendous impact on the capability of the oocyte to generate an embryo after fertilization. The study of the oocyte chromatin by means of classical morphological and histochemical approaches has given a fundamental contribution to our understanding of oocyte biology and has paved the way to functional and mechanistic studies. Several research groups worldwide, including ours, are indeed dedicating a large amount of studies to find the relationship between morphological and functional aspects of the oocyte chromatin remodeling process, to reveal the molecular mechanisms involved, as well as to clarify the contribution of the follicular compartment. Here, we summarize some studies intended to give insight into the mechanism(s) regulating this complex process, including recent findings indicating that ovarian granulosa cells and their coupling with the oocyte through gap junctions are implicated in such a process
Embryonic development of denuded bovine oocytes matured in the presence of intact cumulus-oocyte complexes
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