Role Of Stim1 And Orai1 In Mammalian Oocyte Activation

2014 ◽  
Author(s):  
Satanay Hubrack ◽  
Ethel Adap ◽  
Stefan Feske ◽  
Khaled Machaca
Keyword(s):  
Oocyte Activation ◽  
Mammalian Oocyte

Design of novel oocyte activation methods: The role of zinc

2021 ◽  
Author(s):  
Kyungjun Uh ◽  
Alayna Hay ◽  
Paula Chen ◽  
Emily Reese ◽  
Kiho Lee
Keyword(s):  
Nuclear Transfer ◽  
Meiotic Metaphase ◽  
Oocyte Activation ◽  
Metal Chelators ◽  
Essential Step ◽  
Mammalian Oocyte ◽  
Cellular Events ◽  
Artificial Oocyte Activation ◽  
Artificial Activation

Abstract Oocyte activation occurs at the time of fertilization and is a series of cellular events initiated by intracellular Ca2+ increases. Consequently, oocytes are alleviated from their arrested state in meiotic metaphase II (MII), allowing for the completion of meiosis. Oocyte activation is also an essential step for somatic cell nuclear transfer (SCNT) and an important tool to overcome clinical infertility. Traditional artificial activation methods aim to mimic the intracellular Ca2+ changes which occur during fertilization. Recent studies emphasize the importance of cytoplasmic Zn2+ on oocyte maturation and the completion of meiosis, thus suggesting artificial oocyte activation approaches that are centered around the concentration of available Zn2+in oocytes. Depletion of intracellular Zn2+ in oocytes with heavy metal chelators leads to successful oocyte activation in the absence of cellular Ca2+ changes, indicating that successful oocyte activation does not always depends on intracellular Ca2+ increases. Current findings lead to new approaches to artificially activate mammalian oocytes by reducing available Zn2+ contents, and the approaches improve the outcome of oocyte activation when combined with existing Ca2+ based oocyte activation methods. Here, we review the important role of Ca2+ and Zn2+ in mammalian oocyte activation and development of novel oocyte activation approaches based on Zn2+ availability.

Participation of the ubiquitin-proteasome pathway in rat oocyte activation

Zygote ◽  
2005 ◽  
Vol 13 (1) ◽  
pp. 87-95 ◽  
Author(s):  
Xin Tan ◽  
An Peng ◽  
Yong-Chao Wang ◽  
Yue Wang ◽  
Qing-Yuan Sun
Keyword(s):  
Meiotic Division ◽  
Polar Body ◽  
Meiotic Spindle ◽  
Oocyte Activation ◽  
Parthenogenetic Activation ◽  
Ubiquitin Proteasome Pathway ◽  
Ubiquitin Proteasome ◽  
Proteasome Pathway ◽  
Second Polar Body

The role of the ubiquitin-proteasome pathway (UPP) in mitosis is well known. However, its role in meiotic division is still poorly documented, especially in the activation of mammalian oocytes. In this study, the role of proteasome in the spontaneous and parthenogenetic activation of rat oocytes was investigated. We found that ALLN, an inhibitor of proteasome, when applied to metaphase II oocytes, inhibited spontaneous activation, blocked extrusion of the second polar body (PB) and caused the withdrawal of the partially extruded second PB. ALLN also inhibited the parthenogenetic activation induced by cycloheximide, but had no effect on the formation of pronuclei in activated eggs. In metaphase and anaphase, ubiquitin and proteasome localized to the meiotic spindle, concentrating on both sides of the oocyte–second PB boundary during PB extrusion. This pattern of cellular distribution suggests that UPP may have a role in regulating nuclear division and cytokinesis. Ubiquitin was seen to form a ring around the pronucleus, whereas proteasome was evenly distributed in the pronuclear region. Taken together, our results indicate that (1) UPP is required for the transitions of oocytes from metaphase II to anaphase II and from anaphase II to the end of meiosis; and (2) the UPP plays a role in cytokinesis of the second meiotic division.

scholarly journals Regulation of the meiotic divisions of mammalian oocytes and eggs

2018 ◽  
Vol 46 (4) ◽  
pp. 797-806 ◽  
Author(s):  
Jessica R. Sanders ◽  
Keith T. Jones
Keyword(s):  
Cell Division ◽  
Luteinizing Hormone ◽  
Spindle Assembly Checkpoint ◽  
Asymmetric Cell Division ◽  
Homologous Chromosomes ◽  
Mammalian Oocyte ◽  
Cellular Events ◽  
The Hours ◽  
Meiosis I

Initiated by luteinizing hormone and finalized by the fertilizing sperm, the mammalian oocyte completes its two meiotic divisions. The first division occurs in the mature Graafian follicle during the hours preceding ovulation and culminates in an extreme asymmetric cell division and the segregation of the two pairs of homologous chromosomes. The newly created mature egg rearrests at metaphase of the second meiotic division prior to ovulation and only completes meiosis following a Ca2+ signal initiated by the sperm at gamete fusion. Here, we review the cellular events that govern the passage of the oocyte through meiosis I with a focus on the role of the spindle assembly checkpoint in regulating its timing. In meiosis II, we examine how the egg achieves its arrest and how the fertilization Ca2+ signal allows the initiation of embryo development.

scholarly journals A novel homozygous mutation of phospholipase C zeta leading to defective human oocyte activation and fertilization failure

2020 ◽  
Vol 35 (4) ◽  
pp. 977-985 ◽  
Author(s):  
Peng Yuan ◽  
Cen Yang ◽  
Yixin Ren ◽  
Jie Yan ◽  
Yanli Nie ◽  
...  
Keyword(s):  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Human Oocyte ◽  
Homozygous Mutation ◽  
Whole Genome ◽  
C2 Domain ◽  
Oocyte Activation ◽  
Fertilization Failure ◽  
Human Fertilization

Abstract STUDY QUESTION Is a novel homozygous phospholipase C zeta (PLCζ), c.1658 G>C; p. R553P mutation in the C2 domain associated with the outcomes of recurrent fertilization failure after ICSI? SUMMARY ANSWER PLCζ, c.1658 G>C led to defective human oocyte activation and fertilization failure, while this mutation in the C2 domain of PLCζ did not compromise concentration, motility and chromosome ploidy of sperm. WHAT IS KNOWN ALREADY Sperm-specific PLCζ is now widely considered to be the physiological stimulus that evokes intracellular calcium (Ca2+) oscillations, which are essential for egg activation during mammalian fertilization. Thus far, few genetic studies have shown that different point mutations in the PLCζ gene are associated with male infertility. STUDY DESIGN, SIZE, DURATION This was a basic medical research to assess pathogenicity for novel mutation in the C2 domain of PLCζ during human fertilization. PARTICIPANTS/MATERIALS, SETTING, METHODS Single-cell omics were applied to analyze the DNA methylation state of the fertilization failure oocytes and the ploidy of the patient’s sperm. Whole genome sequencing data for the patient were analyzed for mutations in PLCζ. Sanger sequencing confirmed the presence of a rare variant, and then the mutant and wild-type PLCζ mRNA were injected to observe oocyte activation. MAIN RESULTS AND THE ROLE OF CHANCE The fertilization failure oocytes (n = 4) were triploid and lacking proper DNA demethylation. The whole genome sequencing analysis revealed a novel missense homozygous mutation in PLCζ, c.1658 G>C; p. R553P, which leads to the conversion of arginine 553 to proline. This point mutation does not affect the production of the corresponding protein in sperm. However, microinjection of the mRNA transcribed from the PLCζ R553P mutation gene failed to trigger oocyte activation and the subsequent embryo development. LIMITATIONS, REASONS FOR CAUTION Only one patient with PLCζ mutations was available because of its rare incidence. WIDER IMPLICATIONS OF THE FINDINGS Notably, we discovered a novel homozygous mutation in PLCζ, which results in an abnormal conformation at the C2 domain of the PLCζ protein. Our findings indicate an essential role of PLCζ in human fertilization and the requirement of a normal structure of C2 domain in PLCζ-mediated physiological function. STUDY FUNDING/COMPETING INTEREST(S) This project is funded by the National Natural Science Foundation of China (31571544, 31871482, 31871447) and National Key Research and Development Program (2018YFC1004000, 2017YFA0103801). All authors declared no competing interests. TRIAL REGISTRATION NUMBER Not applicable.

scholarly journals Conservation and divergence of poly(A) tail regulation during the mammalian oocyte-to-embryo transition

2021 ◽  
Author(s):  
Yusheng Liu ◽  
Junxue Jin ◽  
Yiwei Zhang ◽  
Le-Yun Wang ◽  
Chuanxin Zhang ◽  
...  
Keyword(s):  
Length Distribution ◽  
Tail Length ◽  
Mammal Species ◽  
Mammalian Oocyte ◽  
Maternal Mrna ◽  
Post Transcriptional Regulation ◽  
Genome Activation ◽  
Parthenogenetic Embryos ◽  
Zygotic Genome

SUMMARYPoly(A) tail length and non-A residues are vital for oocyte-to-embryo transition (OET) in mice and humans1–5. However, the role of poly(A) tail length and non-A residues during OET in other commonly used mammalian animal models for human diseases remains unexplored. In addition, the degree of conservation in maternal mRNA poly(A) tail dynamics during OET across different mammal species is unknown. Here, we conduct a comparative analysis of the poly(A) tails during OET across four species: mice, rats, pigs, and humans. Dynamics during OET found to be conserved across all four species include: maternal mRNA deadenylation during oocyte maturation and re-polyadenylation after fertilization; a fall-rise trend in poly(A) tail length distribution; a rise-fall trend in the ratio of poly(A) tails with non-A residues; higher abundance of non-A residues in poly(A) tails of maternal mRNA than in zygotic genome activation (ZGA) mRNA; maternal mRNA with U residues degrades faster than those without U residues at the stage when ZGA takes place. While in mice and rats maternal mRNA deadenylation is impaired in parthenogenetic embryos and ZGA inhibition leads to blocked maternal mRNA deadenylation in mice and humans. In contrast, the length of consecutive U residues and the duration time of U residues in poly(A) tail diverges across the four species. Together, these findings reveal that the poly(A) tail mediated maternal mRNA post-transcriptional regulation is highly conserved in mammals with unique divergences in the length and life-span of U residues, providing new insights for the further understanding of OET across different mammals.

227 CALRETICULIN, A 60-kDa PROTEIN, PREVENTS POLYSPERMY IN ZONA PELLUCIDA-FREE PIG OCYTES

2013 ◽  
Vol 25 (1) ◽  
pp. 261
Author(s):  
R. Romar ◽  
C. Soriano-Úbeda ◽  
M. D. Saavedra ◽  
J. Gadea ◽  
M. Avilés ◽  
...  
Keyword(s):  
Zona Pellucida ◽  
Calcium Binding ◽  
Statistical Significance ◽  
P Value ◽  
Oocyte Activation ◽  
Cortical Granules ◽  
Chaperone Protein ◽  
The Mean

After gamete membrane fusion or artificial oocyte activation, cortical granules undergo exocytosis and the released content modifies the zona pellucida (ZP), preventing polyspermy. Calreticulin (CRT), a calcium-binding highly conserved protein of 60 kDa, is contained in cortical granules from hamster eggs (Muñoz-Gotera et al. 2001 Mol. Reprod. Dev. 60), and we recently showed it is exocytosed from chemically activated ZP-free pig oocytes (Romar et al. 2012 Reprod. Fertil. Dev. 24). When pig ZP-enclosed oocytes were incubated with CRT, monospermy was not improved (Romar et al. 2011, Maternal communication with gametes and embryo, p. 72), suggesting that the likely role of CRT in preventing polyspermy might be carried out at the oolemma level. Our objective was to evaluate whether CRT prevents polyspermy in pig ZP-free oocytes by treating the cells with this protein before being inseminated. In vitro-matured cumulus–oocyte complexes (44 h, NCSU-37 medium) were decumulated and ZP was digested with Tyrode’s acid. The ZP-free oocytes were incubated for 30 min in TALP medium supplemented with 0, 100, 1000, and 5000 pg of CRT (ab91577, Abcam, Cambridge, MA, USA) per oocyte. After washing, ZP-free oocytes were inseminated (25 000 sperm mL–1) and gametes were co-cultured for 18 h. Putative zygotes were fixed and stained with Hoechst 33342 to analyse the fertilization results. Four replicates with 30 to 35 oocytes per group were done, and results were analysed by one-way ANOVA. A P-value ≤0.05 was taken to denote statistical significance. Incubation with CRT did not affect penetration rates that were similar among groups (77.12 ± 3.88 and 72.73 ± 4.07, respectively, for the 0- and 5000-pg CRT groups). However, the mean number of sperm per penetrated oocyte decreased from 3.01 ± 0.28 (0-pg group) to 2.07 ± 0.16 (5000-pg group), and monospermy rate increased from 30.77 ± 4.87 (0-pg group) to 52.27 ± 5.36 (5000-pg group; P ≤ 0.05). Incubation with CRT did not affect the number of sperm attached to oolemma, which was similar among all groups (11.45 ± 1.16 v. 10.75 ± 1.17, respectively, for 0 and 5000 pg of CRT). These preliminary data suggest that CRT, a protein exocytosed after oocyte activation, participates in the membrane block to polyspermy in pigs. Future studies to describe the exact mechanism of action of this chaperone protein are necessary. Supported by MEC and FEDER (AGL2009-12512-C02-01).

scholarly journals Selected molecular and microfluidic aspects of mammalian oocyte maturation-perspectives: a review

2011 ◽  
Vol 56 (No. 8) ◽  
pp. 367-378 ◽  
Author(s):  
B. Kempisty ◽  
D. Bukowska ◽  
H. Piotrowska ◽  
P. Zawierucha ◽  
P. Sniadek ◽  
...  
Keyword(s):  
Growth And Development ◽  
Blastocyst Stage ◽  
Normal Embryo ◽  
Zygote Formation ◽  
New Combinations ◽  
Lab On Chip ◽  
Mammalian Oocyte ◽  
On Chip ◽  
Media Supplements

Maturation of oocytes is the most important stage, which determines the subsequent successful fertilization, zygote formation, attainment of blastocyst stage, normal embryo growth and development, as well as appropriate implantation. Since in some species of mammals the efficiency of IVM maturation is still very low, many studies have focused on new combinations of media supplements. In some species of mammals, including pigs, mice, bovines, goats and dogs, EGF, BSA, and progesterone are successfully used as an enhancer of the IVC system. Application of the Lab-on-Chip system in reproductive biology opens new possibilities for the development of techniques available for the assessment of the developmental competency or potency manifested by mammalian oocytes and embryos. In most cases, the Lab-on-Chip system was used in mice. However, an increasing number of examples are available in which the system has been applied to evaluate porcine and bovine gametes and embryos. In this article, the role of EGF, BSA and progesterone is described in relation to maturation efficiency of mammalian oocytes. Moreover, the possibilities of using microfluidics (Lab-on-Chip) for the detection of oocyte developmental competency are also shown.

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