-
Cell Calcium Jan 2014Since the establishment of in vitro fertilization, it became evident that almost half of the couples failed to achieve fertilization and this phenomenon was attributed... (Review)
Review
Since the establishment of in vitro fertilization, it became evident that almost half of the couples failed to achieve fertilization and this phenomenon was attributed to a male gamete dysfunction. The adoption of assisted fertilization techniques particularly ICSI has been able to alleviate male factor infertility by granting the consistent ability of a viable spermatozoon to activate an oocyte. Single sperm injection, by pinpointing the beginning of fertilization, has been an invaluable tool in clarifying the different aspects of early fertilization and syngamy. However, even with ICSI some couples fail to fertilize due to ooplasmic dysmaturity in relation to the achieved nuclear maturation marked by the extrusion of the first polar body. More uncommon are cases where the spermatozoa partially or completely lack the specific oocyte activating factor. In this work, we review the most relevant aspects of fertilization and its failure through assisted reproductive technologies. Attempts at diagnosing and treating clinical fertilization failure are described.
Topics: Calcium; Female; Fertilization; Fertilization in Vitro; Humans; Male; Oocytes; Sperm Injections, Intracytoplasmic; Spermatozoa
PubMed: 24290744
DOI: 10.1016/j.ceca.2013.10.006 -
ELife Jun 2020The fusion of gamete membranes during fertilization is an essential process for sexual reproduction. Despite its importance, only three proteins are known to be...
The fusion of gamete membranes during fertilization is an essential process for sexual reproduction. Despite its importance, only three proteins are known to be indispensable for sperm-egg membrane fusion: the sperm proteins IZUMO1 and SPACA6, and the egg protein JUNO. Here we demonstrate that another sperm protein, TMEM95, is necessary for sperm-egg interaction. TMEM95 ablation in mice caused complete male-specific infertility. Sperm lacking this protein were morphologically normal exhibited normal motility, and could penetrate the zona pellucida and bind to the oolemma. However, once bound to the oolemma, TMEM95-deficient sperm were unable to fuse with the egg membrane or penetrate into the ooplasm, and fertilization could only be achieved by mechanical injection of one sperm into the ooplasm, thereby bypassing membrane fusion. These data demonstrate that TMEM95 is essential for mammalian fertilization.
Topics: Animals; Cell Biology; Cell Membrane; Developmental Biology; Female; Fertilization; Gene Editing; Genes, Reporter; Immunoglobulins; Infertility, Male; Male; Mammals; Membrane Proteins; Mice; Receptors, Cell Surface; Seminal Plasma Proteins; Sperm-Ovum Interactions; Spermatozoa
PubMed: 32484434
DOI: 10.7554/eLife.53913 -
Medecine Sciences : M/S 2004Mitochondria play a primary role in cellular energetic metabolism. They possess their own DNA, which is exclusively maternally transmitted. The relatively recent idea... (Review)
Review
Mitochondria play a primary role in cellular energetic metabolism. They possess their own DNA, which is exclusively maternally transmitted. The relatively recent idea that mitochondria may be directly involved in human reproduction is arousing increasing interest in the scientific and medical community. It has been shown that the functional status of mitochondria contributes to the quality of oocytes and spermatozoa, and plays a part in the process of fertilisation and embryo development. Moreover, new techniques, such as ooplasm transfer, compromise the uniquely maternal inheritance of mitochondrial DNA, raising important ethical questions. This review discusses recent information about mitochondria in the field of human fertility and reproduction.
Topics: Female; Fertility; Humans; Male; Mitochondria
PubMed: 15361344
DOI: 10.1051/medsci/2004208-9779 -
Scientific Reports Jun 2020This study aimed to elucidate the physiological processes of oogenesis in Acropora tenuis. Genes/proteins related to oogenesis were investigated: Vasa, a germ cell...
This study aimed to elucidate the physiological processes of oogenesis in Acropora tenuis. Genes/proteins related to oogenesis were investigated: Vasa, a germ cell marker, vitellogenin (VG), a major yolk protein precursor, and its receptor (LDLR). Coral branches were collected monthly from coral reefs around Sesoko Island (Okinawa, Japan) for histological observation by in situ hybridisation (ISH) of the Vasa (AtVasa) and Low Density Lipoprotein Receptor (AtLDLR) genes and immunohistochemistry (IHC) of AtVasa and AtVG. AtVasa immunoreactivity was detected in germline cells and ooplasm, whereas AtVG immunoreactivity was detected in ooplasm and putative ovarian tissues. AtVasa was localised in germline cells located in the retractor muscles of the mesentery, whereas AtLDLR was localised in the putative ovarian and mesentery tissues. AtLDLR was detected in coral tissues during the vitellogenic phase, whereas AtVG immunoreactivity was found in primary oocytes. Germline cells expressing AtVasa are present throughout the year. In conclusion, Vasa has physiological and molecular roles throughout the oogenic cycle, as it determines gonadal germline cells and ensures normal oocyte development, whereas the roles of VG and LDLR are limited to the vitellogenic stages because they act in coordination with lipoprotein transport, vitellogenin synthesis, and yolk incorporation into oocytes.
Topics: Animals; Anthozoa; DEAD-box RNA Helicases; Gametogenesis; Gene Expression Regulation, Developmental; Germ Cells; In Situ Hybridization; Oocytes; Oogenesis; Receptors, LDL; Seasons; Vitellogenesis; Vitellogenins
PubMed: 32555307
DOI: 10.1038/s41598-020-66020-x -
Mediators of Inflammation 2014Oocyte intracellular lipids are mainly stored in lipid droplets (LD) providing energy for proper growth and development. Lipids are also important signalling molecules... (Review)
Review
Oocyte intracellular lipids are mainly stored in lipid droplets (LD) providing energy for proper growth and development. Lipids are also important signalling molecules involved in the regulatory mechanisms of maturation and hence in oocyte competence acquisition. Recent studies show that LD are highly dynamic organelles. They change their shape, volume, and location within the ooplasm as well as their interaction with other organelles during the maturation process. The droplets high lipid content has been correlated with impaired oocyte developmental competence and low cryosurvival. Yet the underlying mechanisms are not fully understood. In particular, the lipid-rich pig oocyte might be an excellent model to understand the role of lipids and fatty acid metabolism during the mammalian oocyte maturation and their implications on subsequent monospermic fertilization and preimplantation embryo development. The possibility of using chemical molecules to modulate the lipid content of oocytes and embryos to improve cryopreservation as well as its biological effects during development is here described. Furthermore, these principles of lipid content modulation may be applied not only to germ cells and embryo cryopreservation in livestock production but also to biomedical fundamental research.
Topics: Animals; Cell Nucleus; Cryopreservation; Cumulus Cells; Cytoplasm; Embryonic Development; Fatty Acids; Female; Fertilization; Lipid Metabolism; Lipids; Oocytes; Oogenesis; Signal Transduction; Swine
PubMed: 24733963
DOI: 10.1155/2014/692067 -
Zoological Letters Jul 2022The medaka (Oryzias latipes) egg envelope (chorion) is composed of three major glycoproteins, Zona Interna (ZI)-1, -2, and -3, that originate in the spawning female...
The medaka (Oryzias latipes) egg envelope (chorion) is composed of three major glycoproteins, Zona Interna (ZI)-1, -2, and -3, that originate in the spawning female liver as the precursor proteins Choriogenin (Chg.)H, Chg.Hm, and Chg.L, respectively. These ZI and Chg. proteins contain a structural ZP protein domain that is conserved among the egg envelope proteins of all animals. While ovarian expression of ZP proteins (e.g., ZPCs and ZPB) has been reported in medakas, the functions of these proteins remain unknown. Thus, the present study aimed to determine whether the ovary-expressed medaka ZP protein, mZPC5, is involved in forming the chorion matrix.The mZPC5 gene (mzpc5) was expressed in the ovaries but not the livers of mature female medakas, as shown by reverse transcription-polymerase chain reaction assays with mzpc5-specific primers. In situ hybridization analysis revealed that ovarian mzpc5 expression was restricted to the ooplasm of early (stage I-III) previtellogenic oocytes, and its expression signal weakened with oocyte growth. Following sodium-dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting analysis with anti-mZPC5 antibodies, two immunoreactive proteins were detected in the ovary and chorion extracts. These proteins were approximately 50 and 74 kDa in size, like ZI-3 and ZI-2, respectively.Immunohistochemical assays using anti-mZPC5 and anti-Chg.H antibodies localized the mZPC5 protein in the ooplasm of early previtellogenic oocytes. With oocyte growth, mZPC5 tended to accumulate in the chorion, co-localizing with Chg.H.We previously showed that ovary-expressed ZP proteins could not compensate for Chg.L function loss in gene knock-out (chg.l -/-) medakas. As in our previous study, the chg.l-/- females produced oocytes with thin chorions, resulting in infertile soft eggs. However, in the present study, mZPC5 and Chg.H were co-localized in the chg.l-/- chorions. These results suggested that in the medaka previtellogenic oocyte, 1) mZPC5 is secreted from the ooplasm and deposited on the outer surface of its plasma membrane, creating the thin chorion layer; and 2) following the accumulation of liver-derived Chgs., the 3D structure of the chorion matrix is formed cooperatively with mZPC5 and Chgs. during oogenesis. More research is needed to confirm the functions of mZPC5 in chorion structure and physiology.
PubMed: 35902919
DOI: 10.1186/s40851-022-00194-2 -
Developmental Dynamics : An Official... Aug 2005Setting up future body axes is the first important event before and at the beginning of embryogenesis. The ascidian embryo is a classic model that has been used to gain... (Review)
Review
Setting up future body axes is the first important event before and at the beginning of embryogenesis. The ascidian embryo is a classic model that has been used to gain insight into developmental processes for over a century. This review summarizes advances made in this decade in our understanding of the developmental processes involved in the specification of the embryonic axes and cell fates during early ascidian embryogenesis. Maternal factors, including mRNAs, are translocated to specific regions of the egg by cytoplasmic and cortical reorganization, so-called ooplasmic segregation, and specify the animal-vegetal axis and the one perpendicular to it, which is defined as the anteroposterior axis in ascidians. Some postplasmic/PEM RNAs that are anchored to cortical endoplasmic reticulum are brought to the future posterior pole of fertilized eggs, and play crucial roles in posterior development. Following specification of the animal-vegetal axis, nuclear localization of beta-catenin takes place in the vegetal blastomeres; this occurrence is important for the acquisition of the vegetal character of the blastomeres in later development. Positioning of these maternal factors lead to subsequent cell interactions and zygotic gene expression responsible for axis establishment and for cell fate specification. We describe how endoderm blastomeres in the vegetal pole region emanate inductive signals mainly attributable to fibroblast growth factor. Marginal blastomeres next to endoderm blastomeres respond differently in ways that are determined by intrinsic competence factors. Expression patterns of developmentally important genes, including key transcription factors of each tissue type, are also summarized.
Topics: Animals; Body Patterning; Urochordata
PubMed: 15973692
DOI: 10.1002/dvdy.20469 -
Fertility and Sterility Feb 2004Study of the influence of ooplasm transfer on the microtubule dynamics in human postmature oocytes.
OBJECTIVE
Study of the influence of ooplasm transfer on the microtubule dynamics in human postmature oocytes.
DESIGN
Prospective experimental study.
SETTING
Academic hospital-based fertility center. MATERIALS(S): Human in vitro matured (IVM) oocytes (n = 65). Experimental groups: In set 1, sibling oocytes were processed either within 2-3 hours ("young"; n = 16) or at 12-14 hours after maturation ("presumably postmature," or PPM; n = 14). In set 2, young and PPM oocytes (n = 6 and 10, respectively) were assigned to be ooplasm donors and recipients, respectively. In set 3, PPM oocytes were used as ooplasm donors (n = 2) and recipients (n = 4). Control groups: Metaphase II oocytes from superovulated golden hamsters in set 1; sibling oocytes of ooplasm donor young (n = 4) and PPM oocytes (n = 7) in set 2; and sibling PPM oocytes in set 3 (n = 2).
INTERVENTION(S)
Immunocytochemistry for alphatubulin with or without treatment with taxol (Paclitaxel, a microtubule-enhancing agent) in set 1; aspiration and microinjection of approximately 20 picolitres ooplasm from donor young and PPM oocytes into recipient PPM oocytes in sets 2 and 3, respectively. Taxol treatment and tubulin immunocytochemistry on ooplasm recipients and control young and PPM sibling oocytes.
MAIN OUTCOME MEASURE(S)
Morphology and pattern of the microtubules in the spindle and ooplasm as evaluated by confocal microscopy and three-dimensional image reconstructions.
RESULT(S)
In set 1, taxol-untreated young oocytes had normal spindle morphology and orientation to the oolemma with no microtubules in the ooplasm. Taxol-treated young oocytes revealed markedly broadened spindle poles and minimal or absent ooplasmic microtubules. Taxol-untreated PPM oocytes had variable spindle morphology and a notable increase in cortical ooplasmic microtubules. Taxol treatment of PPM oocytes resulted in a marked increase in ooplasmic microtubules in addition to a broadening of spindle poles and formation of polar asters. In set 2, control young and PPM oocytes had the same findings as the corresponding oocytes in set 1. However, all ooplasm recipient PPM oocytes showed a striking diminution in ooplasmic microtubules, despite the taxol treatment, compared with their sibling PPM control oocytes in set 2 and PPM ooplasm-injected PPM oocytes in set 3.
CONCLUSION(S)
Postmature oocytes exhibit a dynamic increase in ooplasmic microtubules. However, these changes revert after transfer of ooplasm from young oocytes.
Topics: Cellular Senescence; Cytoskeleton; Female; Humans; Immunohistochemistry; Microtubules; Oocytes; Paclitaxel; Prospective Studies; Reproductive Techniques, Assisted; Tubulin; Zona Pellucida
PubMed: 14967368
DOI: 10.1016/j.fertnstert.2003.06.033 -
Animals : An Open Access Journal From... Apr 2019The mitogen-activated kinase (MAPK) p38, a member of the MAPK subfamily, is conserved in all mammalian cells and plays important roles in response to various physiologic...
The mitogen-activated kinase (MAPK) p38, a member of the MAPK subfamily, is conserved in all mammalian cells and plays important roles in response to various physiologic cues, including mitogens and heat shock. In the present study, MAPK p38 protein expression in porcine oocytes was analyzed during in vitro maturation (IVM) by Western blotting and immunocytochemistry. The levels of p-p38 or activated p38 and p38 expression were at the lowest in the germinal vesicle (GV) stage oocyte, gradually rising at the germinal vesicle breakdown (GVBD) and then reaching a plateau throughout the IVM culture ( < 0.05). Similarly, the expression level of total p38 was also lower in the GV oocyte than in the oocyte of other meiotic stages and uprising after GVBD and remained high until the metaphase III (MII) stage ( < 0.05). In the GV stage, phosphorylated p38 (p-p38) was initially detectable in the ooplasm and subsequently became clear around the nucleus and localized in the ooplasm at GVBD (18 h post-culture). During the metaphase I (MI) and metaphase II (MII) stages, p-p38 was evenly distributed throughout the ooplasm after IVM for 30 or 42 h. We found that the subcellular localization increased in p-p38 expression throughout oocyte maturation ( < 0.05) and that dynamic reorganization of the cytoskeleton, including microfilaments and microtubules, was progressively changed during the course of meiotic maturation which was likely to be associated with the activation or networking of p38 with other proteins in supporting oocyte development. In conclusion, the alteration of p38 activation is essential for the regulation of porcine oocyte maturation, accompanied by the progressive reorganization and redistribution of the cytoskeleton and MAPK p38, respectively, in the ooplasm.
PubMed: 31013909
DOI: 10.3390/ani9040163 -
Brazilian Journal of Biology = Revista... 2023Specimens of Cnemidocarpa amphora were collected monthly from the Arabian Gulf from September 2017 to August 2018. Parts of their gonads were prepared for histological...
Gonadal proliferation and reproductive cycle of the exotic sea squirt Cnemidocarpa amphora () (Pleurogona, Styelidae) sampled for the first time from the northern coast of Arabian Gulf in Saudi Arabia.
Specimens of Cnemidocarpa amphora were collected monthly from the Arabian Gulf from September 2017 to August 2018. Parts of their gonads were prepared for histological testing. The gonads' diameters varied by month. Each gonad contained many ovarian follicles with different morphologies and was surrounded by several testicular follicles. The ovarian and testicular follicles were separate, although the latter were always present near the former. Repeated measures ANOVA tests were conducted to investigate monthly changes in oocyte stages. In squirts measuring 12-13 cm in length, the gonads measured 30-50 mm from July to August; 20-25 mm from September to October; 15-20 mm from November to February; and 25-40 mm from March to June. Oogonia budded from the germinal epithelium with diameters of 20-30 µm. Previtellogenic oocytes measuring 70-120 µm were characterized by the deposition of small granules of protein around the nucleus, a continuous layer of follicular cuboidal epithelium, and scattered vacuoles in the ooplasm. The measurement of gonads and oocyte diameters were performed by image analysis (Image scope 2.3, Image Line, Inc.) and stage micrometer. The vitellogenic oocytes measured 130-220 µm and the follicular epithelium consisted of flattened and cuboidal layers. Beneath the vitelline membrane, scattered test cells appeared in the ooplasm and different granules of protein and MPS were deposited in the ooplasm. In the later phase, lipid droplets began to appear in the ooplasm. Yolk bodies formed after the impregnation of various granules together and the oocyte was ready to be shed. Before spawning, a yolk membrane appeared above the ooplasm. Post-vitellogenic oocytes, in which the homogeneity of ooplasm was restored, underwent gradual lysis and entered the atretic phase. Different stages of sperm development were present year-round in different follicles of the same squirt; hence, the testes were always mature.
Topics: Animals; Female; Male; Urochordata; Saudi Arabia; Semen; Oocytes; Ovary; Cell Proliferation
PubMed: 37970899
DOI: 10.1590/1519-6984.273666