scholarly journals Parthenogenetic mosaicism: generation via second polar body retention and unmasking of a likely causative PER2 variant for hypersomnia

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Yohei Masunaga ◽  
Masayo Kagami ◽  
Fumiko Kato ◽  
Takeshi Usui ◽  
Takako Yonemoto ◽  
...  
Keyword(s):  
Polar Body ◽  
Cell Lineage ◽  
Rare Condition ◽  
Copy Number Variant ◽  
Causative Factor ◽  
Maternal Origin ◽  
Paternal Origin ◽  
Body Retention ◽  
Idiopathic Hypersomnia ◽  
Second Polar Body

Abstract Background Parthenogenetic mosaicism is an extremely rare condition identified only in five subjects to date. The previous studies indicate that this condition is mediated by parthenogenetic activation and is free from a specific phenotype ascribed to unmaking of a maternally inherited recessive variant in the parthenogenetic cell lineage. Results We examined a 28-year-old Japanese 46,XX female with Silver-Russell syndrome and idiopathic hypersomnia. The results revealed (1) predominance of maternally derived alleles for all the differentially methylated regions examined; (2) no disease-related copy-number variant; (3) two types of regions for all chromosomes, i.e., four BAF (B-allele frequency) band regions with single major microsatellite peaks of maternal origin and single minor microsatellite peaks of non-maternal (paternal) origin, and six BAF band regions with single major microsatellite peaks of maternal origin and two minor microsatellite peaks of maternal and non-maternal (paternal) origin; (4) an unmasked extremely rare PER2 variant (c.1403G>A:p.(Arg468Gln)) with high predicted pathogenicity; (5) mildly affected local structure with altered hydrogen bonds of the p.Arg468Gln-PER2 protein; and (6) nucleus-dominant subcellular distribution of the p.Arg468Gln-PER2 protein. Conclusions The above findings imply that the second polar body retention occurred around fertilization, resulting in the generation of the parthenogenetic cell lineage by endoreplication of a female pronucleus and the normal cell lineage by fusion of male and female pronuclei, and that the homozygous PER2 variant in the parthenogenetic cells is the likely causative factor for idiopathic hypersomnia.

GENE-CENTROMERE MAPPING IN RAINBOW TROUT: HIGH INTERFERENCE OVER LONG MAP DISTANCES

Genetics ◽  
1983 ◽  
Vol 103 (4) ◽  
pp. 771-783
Author(s):  
Gary H Thorgaard ◽  
Fred W Allendorf ◽  
Kathy L Knudsen
Keyword(s):  
Rainbow Trout ◽  
Polar Body ◽  
Practical Method ◽  
Inbred Lines ◽  
Body Retention ◽  
Interference Range ◽  
Gynogenetic Diploid ◽  
Chromosome Arm ◽  
Second Polar Body ◽  
Map Location

ABSTRACT Ten enzyme loci were mapped in relation to their centromeres in gynogenetic diploid rainbow trout. Gene-centromere map distances, calculated under the assumption of complete interference, range from 1.1 cM for Ldh4 to 50 cM for Sod1. The Idh2 and Est1 loci are linked on the same chromosome arm.—The observation of close to 100% heterozygous gynogenetic diploids for the Sod1 and Mdh3,4 loci suggests that near-complete interference occurs on the chromosome arms carrying these loci. The high interference observed in this study and in several other species of fish may be related to the small size of fish chromosome arms.—Comparisons of map locations for the Ldh3 and Ldh4 and the Mdh3 and Mdh4 loci, which were duplicated by a tetraploid event in the evolution of salmonid fish, reveal that they are located at similar distances from their centromeres. Comparative mapping of loci duplicated longer ago shows more variation in map location.—The high proportion of heterozygotes for some loci after gynogenesis involving second polar body retention demonstrates that this is not a practical method for producing homozygous inbred lines in rainbow trout; treatments suppressing the first cell division are more promising for this purpose.

Preservation of sperm within the mouse cauda epididymidis in salt or sugars at room temperature

Zygote ◽  
2010 ◽  
Vol 18 (3) ◽  
pp. 245-256 ◽  
Author(s):  
Tetsuo Ono ◽  
Eiji Mizutani ◽  
Chong Li ◽  
Teruhiko Wakayama
Keyword(s):  
Room Temperature ◽  
Polar Body ◽  
Methylation Status ◽  
Cost Effective ◽  
Oocyte Activation ◽  
Male Gametes ◽  
Effective Manner ◽  
Cell Embryo ◽  
Cauda Epididymidis ◽  
Second Polar Body

SummaryThe development of preservation techniques for male gametes at room temperature might allow us to store them in a simple and cost-effective manner. In this study, we studied the use of pure salt or sugar to preserve the whole cauda epididymidis, because it is known that food can be preserved in this way at room temperature for long periods. Mouse epididymides were placed directly in powdered salt (NaCl) or sugars (glucose or raffinose) for 1 day to 1 year at room temperature. Spermatozoa were recovered from the preserved organs after being rehydrated with medium and then isolated sperm heads were microinjected into fresh oocytes. Importantly, the oocyte activation capacity of spermatozoa was maintained after epididymal storage in NaCl for 1 year, whereas most untreated spermatozoa failed to activate oocytes within 1 month of storage. Pronuclear morphology, the rate of extrusion of a second polar body and the methylation status of histone H3 lysine 9 (H3K9me3) in those zygotes were similar to those of zygotes fertilized with fresh spermatozoa. However, the developmental ability of the zygotes decreased within 1 day of sperm storage. This effect led to nuclear fragmentation at the 2-cell embryo stage, irrespective of the storage method used. Thus, although the preserved sperm failed to allow embryo development, their oocyte activation factors were maintained by salt storage of the epididymis for up to 1 year at room temperature.

Maturation promoting factor in ascidian oocytes is regulated by different intracellular signals at meiosis I and II

Development ◽  
1996 ◽  
Vol 122 (7) ◽  
pp. 1995-2003 ◽  
Author(s):  
G.L. Russo ◽  
K. Kyozuka ◽  
L. Antonazzo ◽  
E. Tosti ◽  
B. Dale
Keyword(s):  
Kinase Activity ◽  
Phase 1 ◽  
Polar Body ◽  
Calcium Transients ◽  
Phase 2 ◽  
Phase 3 ◽  
First Polar Body ◽  
Second Polar Body ◽  
Polar Body Extrusion ◽  
Maturation Promoting Factor

Using the fluorescent dye Calcium Green-dextran, we measured intracellular Ca2+ in oocytes of the ascidian Ciona intestinalis at fertilization and during progression through meiosis. The relative fluorescence intensity increased shortly after insemination in a single transient, the activation peak, and this was followed by several smaller oscillations that lasted for approximately 5 minutes (phase 1). The first polar body was extruded after the completion of the phase 1 transients, about 9 minutes after insemination, and then the intracellular calcium level remained at baseline for a period of 5 minutes (phase 2). At 14 minutes postinsemination a second series of oscillations was initiated that lasted 11 minutes (phase 3) and terminated at the time of second polar body extrusion. Phases 1 and 3 were inhibited by preloading oocytes with 5 mM heparin. Simultaneous measurements of membrane currents, in the whole-cell clamp configuration, showed that the 1–2 nA inward fertilization current correlated temporally with the activation peak, while a series of smaller oscillations of 0.1-0.3 nA amplitude were generated at the time of the phase 3 oscillations. Biochemical characterization of Maturation Promoting Factor (MPF) in ascidian oocytes led to the identification of a Cdc2-like kinase activity. Using p13suc1-sepharose as a reagent to precipitate the MPF complex, a 67 kDa (67 × 10(3) Mr) protein was identified as cyclin B. Histone H1 kinase activity was high at metaphase I and decreased within 5 minutes of insemination reaching a minimum level during phase 2, corresponding to telophase I. During phase 3, H1 kinase activity increased and then decayed again during telophase II. Oocytes preloaded with BAPTA and subsequently inseminated did not generate any calcium transients, nonetheless H1 kinase activity decreased 5 minutes after insemination, as in the controls, and remained low for at least 30 minutes. Injection of BAPTA during phase 2 suppressed the phase 3 calcium transients, and inhibited both the increase in H1 kinase activity normally encountered at metaphase II and second polar body extrusion.

The early development of haploid and aneuploid parthenogenetic embryos

Development ◽  
1975 ◽  
Vol 34 (3) ◽  
pp. 645-655
Author(s):  
Matthew H. Kaufman ◽  
Leo Sachs
Keyword(s):  
Early Development ◽  
Polar Body ◽  
Chromosome Counts ◽  
Cell Stage ◽  
Haploid Chromosome Number ◽  
Stage Of Development ◽  
Morula Stage ◽  
Second Polar Body ◽  
Similar Development ◽  
Parthenogenetic Embryos

The early development of parthenogenetically activated oocytes has been studied in C57BL × CBA-T6T6 (F1T6) translocation heterozygote mice and C57BL × CBA-LAC (F1LAC) mice. All F1T6 oocytes had either a quadrivalent or a univalent-trivalent configuration at meiosis I; no such chromosome configurations were observed in the F1LAC oocytes. At ovulation 36·5 % of the F1T6 oocytes had 19 or 21 chromosomes, whereas 97 % of the F1LAC had the normal haploid chromosome number of 20. After parthenogenetic activation, chromosome counts at metaphase of the first cleavage mitosis were made of the eggs with a single pronucleus following extrusion of the second polar body. These activated eggs had similar frequencies of 19, 20 and 21 chromosomes as had the oocytes at ovulation. The activated 1-cell eggs were transferred to the oviducts of pseudopregnant recipients and the embryos recovered 3 days later. At this stage of development, most of the F1T6 embryos with 19 chromosomes were no longer found, but the frequency of 21-chromosome embryos was similar to the frequency of 21-chromosome oocytes and activated eggs. There was a similar mean number of cells in the embryos with 20 and 21 chromosomes. The results indicate that nearly all the embryos with 19 chromosomes failed to develop, probably beyond the 2-cell stage, whereas oocytes with 21 chromosomes had a similar development to oocytes with 20 chromosomes up to the morula stage.

scholarly journals Mitogen-Activated Protein Kinase and Cell Cycle Progression During Mouse Egg Activation Induced by Various Stimuli

1999 ◽  
Vol 54 (3-4) ◽  
pp. 285-294 ◽  
Author(s):  
Q. Y. Sun ◽  
Y. Lax ◽  
S. Rubinstein ◽  
D. Y. Chen ◽  
H. Breitbart
Keyword(s):  
Protein Kinase ◽  
Map Kinase ◽  
Protein Phosphatase ◽  
Kinase Activity ◽  
Polar Body ◽  
Sperm Chromatin ◽  
Mitogen Activated Protein ◽  
Second Polar Body ◽  
Pronuclear Formation ◽  
Mouse Egg

Abstract A very sensitive method was established for detecting the activity of mitogen-activated protein (MAP) kinase in mouse eggs, and used to follow temporal changes of this kinase during fertilization and sponatenous or chemically-induced parthenogenic activation. MAP kinase activity increased between 1 and 2.5 h post-insemination, at which time the second polar body was emitted and sperm chromatin was dispersed; its activity decreased sharply at 8 h, when pronuclei were formed. Both calcium ionophore A23187 and ethanol simulta­ neously induced pronuclear formation and MAP kinase inactivation in aged eggs 8 h after incubation but less effectively in fresh eggs. The protein kinase inhibitor staurosporine in­duced pronuclear formation and MAP kinase inactivation more quickly than other treat­ ments, with MAP kinase inactivation occurring slightly proceeding pronuclear formation. Okadaic acid, a specific inhibitor of protein phosphatase 1 and 2A , induced increase in MAP kinase activity, and overcame pronuclear formation induced by various stimuli. MAP kinase inactivation preceded pronuclear formation in eggs spontaneously activated by aging in vitro, perhaps due to cytoplasmic degeneration and thus delayed response of nuclear envelope precursors to MAP kinase inactivation. These data suggest that MAP kinase is a key protein kinase regulating the events of mouse egg activation. Increased MAP kinase activity is temporally correlated with the second polar body emission and sperm chromatin decondensation. Although different stimuli (including sperm) may initially act through different mechanisms, they finally inactivate MAP kinase, probably by allowing the action of protein phosphatase, and thus induces the transition to interphase.

scholarly journals Cell cycle modification during the transitions between meiotic M-phases in mouse oocytes

1992 ◽  
Vol 102 (3) ◽  
pp. 457-467 ◽  
Author(s):  
J.Z. Kubiak ◽  
M. Weber ◽  
G. Geraud ◽  
B. Maro
Keyword(s):  
Kinase Activity ◽  
Polar Body ◽  
Metaphase Arrest ◽  
Phosphorylated Proteins ◽  
Mouse Oocytes ◽  
Sequence Of Events ◽  
M Phase ◽  
Second Polar Body ◽  
Polar Body Extrusion ◽  
Centrosomal Proteins

When metaphase II-arrested mouse oocytes (M II) are activated very soon after ovulation, they respond abortively by second polar body extrusion followed by another metaphase arrest (metaphase III, M III; Kubiak, 1989). The M II/M III transition resembles the natural transition between the first and second meiotic metaphases (M I/M II). We observed that a similar sequence of events takes place during these two transitions: after anaphase, a polar body is extruded, the microtubules of the midbody disappear rapidly and a new metaphase spindle forms. The MPM-2 monoclonal antibody (which reacts with phosphorylated proteins associated with the centrosome during M-phase) stains discrete foci of peri-centriolar material only in metaphase arrested oocytes; during both transitional periods, a diffuse staining is observed, suggesting that these centrosomal proteins are dephosphorylated, as in a normal interphase. However, the chromosomes always remain condensed and an interphase network of microtubules is never observed during the transitional periods. Incorporation of 32P into proteins increases specifically during the transitional periods. Pulse-chase experiments, after labeling of the oocytes in M phase with 32P, showed that a 62 kDa phosphoprotein band disappears at the time of polar body extrusion. Histone H1 kinase activity (which reflects the activity of the maturation promoting factor) drops during both transitional periods to the level characteristic of interphase and then increases when the new spindle forms. Both the M I/M II and M II/M III transitions require protein synthesis as demonstrated by the effect of puromycin. These results suggest that the two M-phase/M-phase transitions are probably driven by the same molecular mechanism.

The effect of osmolarity on mouse parthenogenesis

Development ◽  
1974 ◽  
Vol 31 (2) ◽  
pp. 513-526
Author(s):  
M. H. Kaufman ◽  
M. A. H. Surani
Keyword(s):  
Protein Synthesis ◽  
Culture Medium ◽  
Culture Media ◽  
Polar Body ◽  
Amino Acid Mixture ◽  
Culture Conditions ◽  
Follicle Cells ◽  
Acid Mixture ◽  
Second Polar Body

Eggs from (C57B1 × A2G)F1 mice were activated by treatment with hyaluronidase, which removed the follicle cells, and cultured in vitro. Observations were made 6–8 h after hyaluronidase treatment to determine the frequency of activation and the types of parthenogenones induced. Cumulus-free eggs resulting from hyaluronidase treatment were incubated for 2¼ h in culture media of various osmolarities. The frequency of activation was found to be dependent on the postovulatory age of oocytes, while the types of parthenogenones induced were dependent on the osmolarity of the in vitro culture medium and their postovulatory age. Culture in low osmolar medium suppressed the extrusion of the second polar body (2PB). This decreased the incidence of haploid eggs with a single pronucleus and 2PB and immediately cleaved eggs from 97·5% to 42·3% of the activated population. Where 2PB extrusion had been suppressed, 97·4% of parthenogenones contained two haploid pronuclei. Very few were observed with a single and presumably diploid pronucleus. Serial observations from 11 to 18 h after hyaluronidase treatment were made on populations of activated eggs as they entered the first cleavage mitosis after 2¼ h incubation in medium either of normal (0·287 osmol) or low (0·168 osmol) osmolarity. A delay in the time of entry into the first cleavage mitosis similar to the duration of incubation in low osmolar medium was observed. Further, eggs were incubated in control and low osmolar culture media containing uniformly labelled [U-14C]amino acid mixture to examine the extent of protein synthesis in recently activated eggs subjected to these culture conditions. An hypothesis is presented to explain the effect of incubation in low osmolar culture medium in delaying the first cleavage mitosis.

Fertilization and ooplasmic movements in the ascidian egg

Development ◽  
1989 ◽  
Vol 105 (2) ◽  
pp. 237-249 ◽  
Author(s):  
C. Sardet ◽  
J. Speksnijder ◽  
S. Inoue ◽  
L. Jaffe
Keyword(s):  
Polar Body ◽  
Surface Velocity ◽  
Second Phase ◽  
Animal Pole ◽  
Male Pronucleus ◽  
Vegetal Pole ◽  
Female Pronucleus ◽  
Ooplasmic Segregation ◽  
Second Polar Body ◽  
Sperm Aster

Using light microscopy techniques, we have studied the movements that follow fertilization in the denuded egg of the ascidian Phallusia mammillata. In particular, our observations show that, as a result of a series of movements described below, the mitochondria-rich subcortical myoplasm is split in two parts during the second phase of ooplasmic segregation. This offers a potential explanation for the origin of larval muscle cells from both posterior and anterior blastomeres. The first visible event at fertilization is a bulging at the animal pole of the egg, which is immediately followed by a wave of contraction, travelling towards the vegetal pole with a surface velocity of 1.4 microns s-1. This wave accompanies the first phase of ooplasmic segregation of the mitochondria-rich subcortical myoplasm. After this contraction wave has reached the vegetal pole after about 2 min, a transient cytoplasmic lobe remains there until 6 min after fertilization. Several new features of the morphogenetic movements were then observed: between the extrusion of the first and second polar body (at 5 and 24–29 min, respectively), a series of transient animal protrusions form at regular intervals. Each animal protrusion involves a flow of the centrally located cytoplasm in the animal direction. Shortly before the second polar body is extruded, a second transient vegetal lobe (‘the vegetal button’) forms, which, like the first, resembles a protostome polar lobe. Immediately after the second polar body is extruded, three events occur almost simultaneously: first, the sperm aster moves from the vegetal hemisphere to the equator. Second, the bulk of the vegetally located myoplasm moves with the sperm aster towards the future posterior pole, but interestingly about 20% remains behind at the anterior side of the embryo. This second phase of myoplasmic movement shows two distinct subphases: a first, oscillatory subphase with an average velocity of about 6 microns min-1, and a second steady subphase with a velocity of about 26 microns min-1. The myoplasm reaches its final position as the male pronucleus with its surrounding aster moves towards the centre of the egg. Third, the female pronucleus moves towards the centre of the egg to meet with the male pronucleus. Like the myoplasm, the migrations of both the sperm aster and the female pronucleus shows two subphases with distinctly different velocities. Finally, the pronuclear membranes dissolve, a small mitotic spindle is formed with very large asters, and at about 60–65 min after fertilization, the egg cleaves.

Sign in / Sign up

Export Citation Format

Share Document