BOD is a Bcl-2-related Ovarian Death agonist. It is also known as Bim, a Bcl-2 Interacting Molecule. Hsu et al 1998 reported BOD (Bcl-2-related ovarian death gene) is an ovarian BH3 domain-containing
proapoptotic Bcl-2 protein capable of dimerization with diverse antiapoptotic
Bcl-2 members.After overexpression in mammalian Chinese
hamster ovary (CHO) cells, BOD induces apoptosis that can be prevented by the
baculoviral caspase inhibitor P35. The cell-killing activity of BOD is also
antagonized in cells cotransfected with the antiapoptotic Bcl-w protein, which
showed high affinity for BOD in the two-hybrid assay.
NCBI Summary:
The protein encoded by this gene belongs to the BCL-2 protein family. BCL-2 family members form hetero- or homodimers and act as anti- or pro-apoptotic regulators that are involved in a wide variety of cellular activities. The protein encoded by this gene contains a Bcl-2 homology domain 3 (BH3). It has been shown to interact with other members of the BCL-2 protein family and to act as an apoptotic activator. The expression of this gene can be induced by nerve growth factor (NGF), as well as by the forkhead transcription factor FKHR-L1, which suggests a role of this gene in neuronal and lymphocyte apoptosis. Transgenic studies of the mouse counterpart suggested that this gene functions as an essential initiator of apoptosis in thymocyte-negative selection. Several alternatively spliced transcript variants of this gene have been identified. [provided by RefSeq, Jun 2013]
General function
Cell death/survival, Apoptosis
Comment
Bim provokes apoptosis, and the BH3 region is required for Bcl-2 binding and for most of its cytotoxicity. Like Bcl-2, Bim possesses a hydrophobic C-terminus and localizes to intracytoplasmic membranes. Three Bim isoforms, probably generated by alternative splicing, all induce apoptosis, the shortest being the most potent (O'Connor et al., 1998).
Mutagenesis studies showed that BOD mutants with alterations in the BH3 domain lose cell-killing ability, suggesting that the BH3 domain is important for the mediation of cell killing by BOD (Hsu et al., 1998).
Cellular localization
Cytoplasmic
Comment
Ovarian function
Follicle atresia, Early embryo development
Comment
Dynamics and Regulations of BimEL Ser65 and Thr112 Phosphorylation in Porcine Granulosa Cells during Follicular Atresia. Yang F et al. (2020) BimEL protein is involved in follicular atresia by regulating granulosa cell apoptosis, but the dynamic changes of BimEL phosphorylation during follicular atresia are poorly understood. The aim of this study was to explore the changes of key BimEL phosphorylation sites and their upstream regulatory pathways. First, the levels of BimEL-Ser65 and BimEL-Thr112 phosphorylation (p-BimEL-S65, p-BimEL-T112) in granulosa cells (GC) from healthy (H), slightly-atretic (SA), and atretic (A) follicles and in cultured GC after different treatments were detected by Western blotting. Next, the effects of the corresponding site mutations of BIM on apoptosis of GC were investigated. Finally, the pathways of two phosphorylation sites were investigated by kinase inhibitors. The results revealed that p-BimEL-S65 levels were higher in GC from H than SA and A, whereas p-BimEL-T112 was reversed. The prosurvival factors like FSH and IGF-1 upregulated the level of p-BimEL-S65, while the proapoptotic factor, heat stress, increased the level of p-BimEL-T112 in cultured GC. Compared with the overexpression of wild BimEL, the apoptotic rate of the GC overexpressed BimEL-S65A (replace Ser65 with Ala) mutant was significantly higher, but the apoptotic rate of the cells overexpressing BimEL-T112A did not differ. In addition, inhibition of the ERK1/2 or JNK pathway by specific inhibitors reduced the levels of p-BimEL-S65 and p-BimEL-T112. In conclusion, the levels of p-BimEL-S65 and p-BimEL-T112 were reversed during follicular atresia. Prosurvival factors promote p-BimEL-S65 levels via ERK1/2 to inhibit GC apoptosis, whereas proapoptotic factor upregulates the level of p-BimEL-T112 via JNK to induce GC apoptosis.////////////////// BIM(EL)-mediated apoptosis in cumulus cells contributes to degenerative changes in aged porcine oocytes via a paracrine action. Wu Y et al. Whether cumulus cells (CCs) contribute to oocyte aging remains controversial; in that regard, little is known about biochemical processes of gene expression in CCs surrounding aged oocytes. The objective was to elucidate contributions of CCs to porcine oocyte aging and degeneration, apoptosis and BIM expression in CCs during oocyte aging in vitro. When culture of cumulus oocyte complexes (COCs) was prolonged (68 h, which resulted in 24 h of aging), the rate of blastocyst formation following electro-activation was lower than that of oocytes aged without CCs (2.6 ? 0.1 vs 13.5 ? 1.3%, mean ? SEM; P < 0.05). In addition, the presence of CCs significantly accelerated spontaneous fragmentation of oocytes following prolonged (92 h) culture. Apoptotic CCs were present in COCs cultured for 68 h, and the abundance of Bim mRNA in CCs progressively increased after 56 h of culture (P < 0.05). Based on immunofluorescence, BIM protein expression was up-regulated in CCs surrounding aged oocytes; furthermore, quantification (Western blot) of BIM(EL) protein progressively increased after 56 h of culture. Lastly, in a series of experiments to elucidate the signal pathway, blocking gap junctions (with 1-octanol) during aging did not eliminate the effect of CCs on accelerating oocyte aging, but prolonged co-culture of denuded oocytes with COCs after in vitro maturation reduced blastocyst rate relative to culture of denuded oocytes aged alone (4.15 ? 0.1 vs 11.0 ? 0.7%, P < 0.05). We concluded that apoptotic CCs, in which BIM(EL) up-regulation was involved, accelerated oocyte aging and degeneration in vitro via a paracrine action.
A non-invasive test for assessing embryo potential by gene expression profiles of human cumulus cells: a proof of concept study. Assou S et al. Background Identification of new criteria for embryo quality is required to improve the clinical outcome of in vitro fertilization (IVF). The aim of this study was to determine the gene expression profile of cumulus cells (CC) surrounding the oocyte as biomarkers for embryo potential and to identify genes to be used as prognostic indicators of successful pregnancy. Methods CC from single oocytes were analyzed using DNA microarrays. Gene expression profiles of CC surrounding the oocyte associated with good embryonic quality and pregnancy outcome were computed. Results We observed that CC issued from oocytes that developed into embryos with a good morphology had differing gene expression profile according to the pregnancy outcome of the embryo. We demonstrated that the expression of BCL2L11, PCK1 and NFIB in CC is significantly correlated with embryo potential and successful pregnancy. These results were confirmed by quantitative RT-PCR. Conclusion The gene expression profiling of human CC correlates with embryo potential and pregnancy outcome. BCL2L11, PCK1 and NFIB genes are proposed as biomarkers for predicting pregnancy. Our findings suggest a non invasive approach, offering a new potential strategy for competent embryo selection. This approach should be validated in single embryo transfer (SET) programs.
Expression regulated by
Growth Factors/ cytokines, insulin
Comment
IGF-1 Inhibits Apoptosis of Porcine Primary Granulosa Cell by Targeting Degradation of BimEL. Han Y et al. (2019) Insulin-like growth factor-1 (IGF-1) is an intra-ovarian growth factor that plays important endocrine or paracrine roles during ovarian development. IGF-1 affects ovarian function and female fertility through reducing apoptosis of granulosa cells, yet the underlying mechanism remains poorly characterized. Here, we aimed to address these knowledge gaps using porcine primary granulosa cells and examining the anti-apoptotic mechanisms of IGF-1. IGF-1 prevented the granulosa cell from apoptosis, as shown by TUNEL and Annexin V/PI detection, and gained the anti-apoptotic index, the ratio of Bcl-2/Bax. This process was partly mediated by reducing the pro-apoptotic BimEL (Bcl-2 Interacting Mediator of Cell Death-Extra Long) protein level. Western blotting showed that IGF-1 promoted BimEL phosphorylation through activating p-ERK1/2, and that the proteasome system was responsible for degradation of phosphorylated BimEL. Meanwhile, IGF-1 enhanced the Beclin1 level and the rate of LC3 II/LC3 I, indicating that autophagy was induced by IGF-1. By blocking the proteolysis processes of both proteasome and autophagy flux with MG132 and chloroquine, respectively, the BimEL did not reduce and the phosphorylated BimEL protein accumulated, thereby indicating that both proteasome and autophagy pathways were involved in the degradation of BimEL stimulated by IGF-1. In conclusion, IGF-1 inhibited porcine primary granulosa cell apoptosis via degradation of pro-apoptotic BimEL. This study is critical for us to further understand the mechanisms of follicular survival and atresia regulated by IGF-1. Moreover, it provides a direction for the treatment of infertility caused by ovarian dysplasia, such as polycystic ovary syndrome and the improvement of assisted reproductive technology.//////////////////
Insulin mitigates apoptosis of porcine follicular granulosa cells by downregulating BimEL. Han Y et al. (2019) Follicular growth or atresia is governed by the survival and apoptosis of granulosa cells. Increasing evidence shows that follicle growth is influenced by energy intake, which is positively related to insulin levels. However, the function of insulin in granulosa cell survival is poorly understood. This study focused on the effects of insulin on porcine medium follicle granulosa cell survival. In the present study, we showed that insulin markedly mitigated the apoptosis of porcine granulosa cells following serum starvation. Moreover, insulin activated the PI3K/Akt pathway to downregulate bim mRNA expression and simultaneously promoted the phosphorylation of BimEL through activating ERK 1/2, both of which reduced the level of BimEL. The results demonstrate that insulin protected the granulosa cells against apoptosis by reducing levels of the pro-apoptotic protein BimEL. However, the concentration of insulin (1 μg/ml) was relatively high. High levels of insulin partly combined with the IGF-1 receptor to play its roles in granulosa cells. This experiment provides new insight into the role of insulin in granulosa cells and sheds light on nutrition-reproduction interactions.//////////////////
Oocyte-Secreted Growth Differentiation Factor 9 Inhibits BCL-2-Interacting Mediator of Cell Death-Extra Long Expression in Porcine Cumulus Cell. Wang XL 2013 et al.
Oocyte-secreted factors (OSFs) maintain the low incidence of cumulus cell apoptosis. In this report, we described that the presence of oocytes suppressed the expression of pro-apoptotic protein BCL-2-interacting mediator of cell death-extra long (BIMEL) in porcine cumulus cells. Atretic (TUNEL-positive) cumulus cells strongly expressed BIMEL protein. The healthy cumulus-oocyte complex (COCs) exhibited a low BIMEL expression in cumulus cell while the removal of oocyte led to an about 2.5 fold (P < 0.5) increased expression in oocytectomized complex (OOX). Co-culturing OOXs with denuded oocytes decreased BIMEL expression to the normal level. The similar expression pattern could also be achieved in the OOXs treated with exogenous recombinant mouse growth differentiation factor 9 (GDF9), a well-characterized OSF. This inhibitory action of GDF9 was prevented by the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002. Luciferase assay further demonstrated that BIM gene expression was forkhead box O3a (FOXO3a)-dependent as mutation of FOXO3a-binding site on the BIM promoter inhibited luciferase activities. Moreover, the activity of BIM promoter encompassing FOXO3a-binding site could be regulated by GDF9. Additionally, we found that GDF9 elevated the levels of phosphorylated AKT and FOXO3a, and this process was independent of SMAD signal pathway. Taken together, we concluded that OSFs, particularly GDF9, maintained the low level of BIMEL expression in cumulus cell through activation of the PI3K/FOXO3a pathway.
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Ovarian localization
Cumulus, Granulosa
Comment
Hsu et al 1998 identified BOD based on yeast 2-hybrid screen of a rat ovary cDNA library.
Expression and Function of Apoptosis Initiator FOXO3 in Granulosa Cells During Follicular Atresia in Pig Ovaries. Matsuda F et al. In mammalian ovaries, most follicles are lost by atresia before ovulation. It has become apparent that the apoptosis of granulosa cells induces follicular atresia. Forkhead box O3 (FOXO3), also called FKHRL1 (forkhead in rhabdomyosarcoma-like 1), is a proapoptotic molecule that belongs to the FOXO subfamily of forkhead transcription factors. Foxo3-deficient female mice were reported to be infertile because of abnormal ovarian follicular development, but the precise influences of FOXO3 on follicular atresia of mature ovary have not been determined. Therefore, we examined the expression and function of FOXO3 in porcine ovarian follicles and granulosa-derived cells. FOXO3 mRNA levels in granulosa cells of porcine ovaries increased during atresia, while FOXO3 protein was abundant in granulosa cells of early atretic follicles. By immunohistochemistry, the inner surface area of the granulosa layer in early atretic follicles was strongly stained with anti-FOXO3 antibody. The granulosa cells expressing FOXO3 coincided with apoptotic cells, indicating a role of FOXO3 as a proapoptotic factor in granulosa cells of porcine ovaries. In porcine (JC-410) and human (KGN) granulosa-derived cells, cell death was induced by transfection of FOXO3 expression vectors. Expression of the proapoptotic factors Fas ligand (FASLG) and BCL2-like 11 (BCL2L11) was upregulated by FOXO3 in KGN cells. In conclusion, FOXO3 is expressed in porcine ovarian follicles and induces apoptosis in granulosa cells, suggesting that it is a candidate for the initiator of follicular atresia.
Follicle stages
Comment
Phenotypes
Mutations
1 mutations
Species: mouse
Mutation name: None
type: null mutation fertility: fertile Comment: Gene targeting in mice revealed important physiological roles for bim/BOD. Lymphoid and myeloid cells accumulated, T cell development was perturbed, and most older mice accumulated plasma cells and succumbed to autoimmune kidney disease. Lymphocytes were refractory to apoptotic stimuli such as cytokine deprivation, calcium ion flux, and microtubule perturbation but not to others Bouillet P et al .