Faculty Opinions recommendation of The APC/C activator FZR1 coordinates the timing of meiotic resumption during prophase I arrest in mammalian oocytes.

2011 ◽  
Author(s):  
Noriyuki Sagata
Keyword(s):  
Prophase I

Etoposide results in follicle loss in the fetal mouse ovary, but does not block the ability of oocytes to progress through prophase I of meiosis

2016 ◽  
Author(s):  
Agnes Stefansdottir ◽  
Zoe Johnston ◽  
Nicola Powles-Glover ◽  
Richard Anderson ◽  
Ian Adams ◽  
...  
Keyword(s):  
Mouse Ovary ◽  
Fetal Mouse ◽  
Prophase I

The influence of Robertsonian translocations on semen parameters

2020 ◽  
pp. 87-88
Author(s):  
М.В. Андреева ◽  
М.И. Штаут ◽  
Т.М. Сорокина ◽  
Л.Ф. Курило ◽  
В.Б. Черных
Keyword(s):  
Male Infertility ◽  
Semen Parameters ◽  
Meiotic Arrest ◽  
Robertsonian Translocations ◽  
Prophase I ◽  
Infertile Men ◽  
Fertility Problems ◽  
Spermatogenesis Impairment

Обследованы 19 мужчин с нарушением фертильности, носителей транслокаций rob(13;14) и rob(13;15). Показано, что нарушение репродуктивной функции обусловлено блоком сперматогенеза в профазе I мейоза, приводящего к азооспермии или олигоастенотератозооспермии и мужскому бесплодию. We examined 19 infertile men, carriers of translocations rob (13;14) and rob (13;15). We assume that fertility problems are resulted from spermatogenesis impairment because of meiotic arrest at prophase I stages, that leads to azoospermia or oligoastenoteratozoospermia and male infertility.

scholarly journals ORIENTATION DISRUPTOR (ord): A RECOMBINATION-DEFECTIVE AND DISJUNCTION-DEFECTIVE MEIOTIC MUTANT IN DROSOPHILA MELANOGASTER

Genetics ◽  
1976 ◽  
Vol 84 (3) ◽  
pp. 545-572
Author(s):  
James M Mason
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Map ◽  
Crossing Over ◽  
Prophase I ◽  
Sister Chromatids

ABSTRACT The effects of a semidominant autosomal meiotic mutant, orientation disruptor (symbol: ord), located at 2-103.5 on the genetic map and in region 59B-D of the salivary map, have been examined genetically and cytologically. The results are as follows. (1) Crossing over in homozygous females is reduced to about seven percent of controls on all chromosomes, with the reduction greatest in distal regions. (2) Crossing over on different chromosomes is independent. (3) Reductional nondisjunction of any given chromosome is increased to about thirty percent of gametes from homozygous females. The probability of such nondisjunction is the same among exchange and nonexchange tetrads with the exception that a very proximal exchange tends to regularize segregation. (4) Equational nondisjunction of each chromosome is increased to about ten percent of gametes in homozygous females; this nondisjunction is independent of exchange. (5) The distributive pairing system is operative in homozygous females. (6) In homozygous males, reductional nondisjunction of each chromosome is increased to about ten percent, and equational nondisjunction to about twenty percent, of all gametes. (7) Cytologically, two distinct meiotic divisions occur in spermatocytes of homozygous males. The first division looks normal although occasional univalents are present at prophase I and a few lagging chromosomes are seen at anaphase I. However, sister chromatids of most chromosomes have precociously separated by metaphase II. Possible functions of the ord+ gene are considered.

Ultrastructure of meiosis and the spindle pole body cycle in freeze-substituted basidia of the smut fungi Ustilago maydis and Ustilago avenae

1992 ◽  
Vol 70 (3) ◽  
pp. 629-638 ◽  
Author(s):  
Kerry O'Donnell
Keyword(s):  
Electron Microscopy ◽  
Spindle Pole Body ◽  
Ustilago Maydis ◽  
Spindle Pole ◽  
Meiotic Spindle ◽  
Smut Fungi ◽  
Late Prophase ◽  
Prophase I ◽  
Pole Body ◽  
Middle Piece

Meiosis in the smut fungi Ustilago maydis and Ustilago avenae (Basidiomycota, Ustilaginales) was studied by electron microscopy of serial-sectioned freeze substituted basidia. At prophase I, a spindle pole body composed of two globular elements connected by a middle piece was attached to the extranuclear surface of each nucleus. Astral and spindle microtubules were initiated at each globular element at late prophase I to prometaphase I. During spindle initiation, the middle piece disappeared and interdigitating half-spindles entered the nucleoplasm, which was surrounded by discontinuous nuclear envelope together with perinuclear endoplasmic reticulum. Kinetochore pairs at metaphase I were analyzed to obtain a karyotype for each species. The meiotic spindle pole body replicational cycle is described. Key words: electron microscopy, freeze-substitution, meiosis, Ustilago, spindle pole body.

scholarly journals The CSN/COP9 Signalosome Regulates Synaptonemal Complex Assembly during Meiotic Prophase I of Caenorhabditis elegans

PLoS Genetics ◽  
2014 ◽  
Vol 10 (11) ◽  
pp. e1004757 ◽  
Author(s):  
Heather Brockway ◽  
Nathan Balukoff ◽  
Martha Dean ◽  
Benjamin Alleva ◽  
Sarit Smolikove
Keyword(s):  
Caenorhabditis Elegans ◽  
Synaptonemal Complex ◽  
Meiotic Prophase ◽  
Cop9 Signalosome ◽  
Complex Assembly ◽  
Prophase I ◽  
Meiotic Prophase I

scholarly journals Kinase CDK2 in Mammalian Meiotic Prophase I: Screening for Hetero- and Homomorphic Sex Chromosomes

2021 ◽  
Vol 22 (4) ◽  
pp. 1969
Author(s):  
Sergey Matveevsky ◽  
Tsenka Chassovnikarova ◽  
Tatiana Grishaeva ◽  
Maret Atsaeva ◽  
Vasilii Malygin ◽  
...  
Keyword(s):  
Sex Chromosomes ◽  
Mammalian Species ◽  
Critical Role ◽  
Eukaryotic Cell ◽  
Repair System ◽  
Prophase I ◽  
Meiotic Chromosomes ◽  
Y Chromosomes ◽  
Dna Mismatch Repair System ◽  
Male Sex

Cyclin-dependent kinases (CDKs) are crucial regulators of the eukaryotic cell cycle. The critical role of CDK2 in the progression of meiosis was demonstrated in a single mammalian species, the mouse. We used immunocytochemistry to study the localization of CDK2 during meiosis in seven rodent species that possess hetero- and homomorphic male sex chromosomes. To compare the distribution of CDK2 in XY and XX male sex chromosomes, we performed multi-round immunostaining of a number of marker proteins in meiotic chromosomes of the rat and subterranean mole voles. Antibodies to the following proteins were used: RAD51, a member of the double-stranded DNA break repair machinery; MLH1, a component of the DNA mismatch repair system; and SUN1, which is involved in the connection between the meiotic telomeres and nuclear envelope, alongside the synaptic protein SYCP3 and kinetochore marker CREST. Using an enhanced protocol, we were able to assess the distribution of as many as four separate proteins in the same meiotic cell. We showed that during prophase I, CDK2 localizes to telomeric and interstitial regions of autosomes in all species investigated (rat, vole, hamster, subterranean mole voles, and mole rats). In sex bivalents following synaptic specificity, the CDK2 signals were distributed in three different modes. In the XY bivalent in the rat and mole rat, we detected numerous CDK2 signals in asynaptic regions and a single CDK2 focus on synaptic segments, similar to the mouse sex chromosomes. In the mole voles, which have unique XX sex chromosomes in males, CDK2 signals were nevertheless distributed similarly to the rat XY sex chromosomes. In the vole, sex chromosomes did not synapse, but demonstrated CDK2 signals of varying intensity, similar to the rat X and Y chromosomes. In female mole voles, the XX bivalent had CDK2 pattern similar to autosomes of all species. In the hamster, CDK2 signals were revealed in telomeric regions in the short synaptic segment of the sex bivalent. We found that CDK2 signals colocalize with SUN1 and MLH1 signals in meiotic chromosomes in rats and mole voles, similar to the mouse. The difference in CDK2 manifestation at the prophase I sex chromosomes can be considered an example of the rapid chromosome evolution in mammals.

Intranuclear membranous inclusions in oocytes of a viviparous teleost (Xiphophorus helleri)

1976 ◽  
Vol 22 (2) ◽  
pp. 325-334
Author(s):  
C. Azevedo
Keyword(s):  
Nuclear Membrane ◽  
Inclusion Bodies ◽  
Intranuclear Inclusions ◽  
Late Prophase ◽  
Xiphophorus Helleri ◽  
Inner Nuclear Membrane ◽  
Prophase I ◽  
Fixed Material ◽  
Metabolic Phenomena

Intranuclear inclusions were observed in oocytes of Xiphophorus helleri during prophase I. In osmium-fixed leptotene nuclei, the inclusions were made up of groups of membrane-limited vesicles or tubules with pale contents, situated near the inner nuclear membrane with which some of them exhibited apparent continuities. In zygotene nuclei, larger vesicles also appeared bounded by two or three membranes and containing tubules apparently invaginated from their walls. In pachytene-dictyate nuclei most vesicular bodies had a wall formed by stratified membranes, or were entirely made up of membranous whorls. In glutaraldehyde-osmium fixed material some of these myeline-like bodies showed a peculiar arrangement, consisting of concentric bands each containing thick inner dense lamellae 2-0-3-0 nm thick and a 5-0 nm outer lamella. It is suggested that these inclusion bodies arise from the inner nuclear membrane of oocytes when cells start to grow intensely during prophase I. The bodies seem to become more complex at late prophase, probably by association of individual vesicles and the occurrence of multiple membrane invaginations, which may be related to active metabolic phenomena taking place at this stage in oocytes.

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