Name: isolation and characterization of mouse antral oocytes based on nucleolar chromatin organization
Uploaded: 2016-01-07T12:00:01.000+00:00
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Description: Watch this Scientific Journal Video about Isolation and Characterization of Mouse Antral Oocytes Based on Nucleolar Chromatin Organization at JoVE.com

M.M. and C.A.R. acknowledge the financial support of the Ministero della Salute, Ricerca Finalizzata/giovani ricercatori anno 2009 of the Fondazione IRCCS Ospedale San Matteo, Pavia (I). M.M and C.A.R. wish to thank Marianna Longo for helping with the images preparation.

Bu protokol Avrupa rehber ilkeler (AB 63/2010) ve bilimsel araştırmalar için kullanılan hayvanların korunması İtalyan (26/2014) yasalara uygun olarak yapılmaktadır. Servikal dislokasyon ötenazi yumurtalıkların izolasyonu için kullanılır ve bu çalışmayı kapsayan onaylanan protokole listelenen kişilerin uzman tarafından gerçekleştirilen ve eğitimli. 1. Hayvanlar <ol><li> Kontrollü sıcaklık ve nem ile bir odada 6 haftalık dişi farelere yetişkin 3- Bakım (12L evreleri ile: 12D ve beslenmiş ad libitum). </li><li> Folikül uyarıcı hormon (FSH) etkisini taklit ederek foliküler büyümesini teşvik etmek için Gebe kısrak serum gonadotropini 2.5 IU (PMSG) intraperitoneal olarak farelere enjekte ile. Daha sonra antral oosit toplama 48 saat için yumurtalıklar izole edin. Senin kurumsal kurallarına göre, daha önce PMSG enjekte dişi fare Euthanize. </li><li> Hızla vücut boşluğundan yumurtalıkların kaldırmak ve petri cont içine yerleştirinsonraki oosit izolasyonu için M2 orta Aining (Bölüm 3). <ol><li> Steril diseksiyon makas kullanarak periton bir kesi ardından karın duvarı kaplayan deride bir kesi yapmak. Mesane başlayarak V-şekli oluşturan, karın ortaya çıkarmak için kesik açıldı steril cımbız kullanarak bir tarafında cesaret taşımak ve uterin tüpleri lokalize. </li><li> Böbrekler altında bulunan yumurtalıklar uyun. Steril cımbız ile her tüp tutun ve onları serbest bırakmak için yumurtalıkların dibinde küçük bir kesi yapmak. Önceden dengelenmiş ortamını içeren bir petri kabı altındaki iki yumurtalık aktarın. </li></ol></li></ol> 2. Hormon Hazırlık <ol><li> Uygun bir enjeksiyon hacmi için 0.1 ml başına 2,5 IU hormonu çalışma konsantrasyonu elde etmek üzere, steril izotonik tuzlu su çözeltisi ile (başka bir stok çözeltilerinden mevcuttur) PMSG seyreltilir. Not: Hormon çözeltiler 0.5 ml tüpler içinde alikotlandı ve saklanmalı -2Kullanım güne kadar 0 ° C. -20 ° C&#39;de üç aydan uzun seyreltilmiş alikotları tutmayın. Çözülmüş kez seri enjeksiyonlar yapılır, eğer 4 ° C&#39;de hormon çözümleri hacimde depolamak ve 4 gün içinde bunları kullanmak. </li></ol> 3. Antral oositler İzolasyonu Doğru oosit izolasyonu için: <ol><li> Oositler izolasyon prosedürü başlamadan önce en az 1 saat boyunca% 5 CO2 ve 37 ° C M2 ortamı 13 (M2) dengelenmesi. İki petri kaplarına (35 mm x 10 mm), yumurtalık delme ve ayrıştırıldıktan sonra, oosit transferi için, mineral yağ (yaklaşık 1.5 mi) ile kaplanmış M2 küçük damla ikinci bir (20 ul) için M2 1 ml ile bir hazırlama yumurtalık (3.4-3.6 bakınız). Kullanılmaya hazır kadar% 5 CO2 ve 37 ° C&#39;de inkübatör içinde iki petri kaplarına tutun. </li><li> Oosit izolasyon işlemleri sırasında Stereomikroskopta kullanın. </li><li> Stretç tarafından oosit toplamak için ince ağız cam pipetler hazırlayınhing cam Pasteur pipetler Bunsen beki gelen dikey bir alev (Şekil 1) üzerinden, (iki elinizle pipet uçlarını tutarak) yatay tuttu. <ol><li> Cam erimeye başladığında, alev dışarı pipetlemeyin almak ve istenen pipet elde etmek için hızlı bir çekme hareketi gerçekleştirin. Sıkıca uzunluğu ve iç kılcal çapını ayarlamak için tırnaklarıyla pipet dar noktasına yakın aşırı cam kesti. İnce kılcal oositin çapından biraz daha büyük ~ 100 um bir iç çapa sahip olduğundan emin olun (~ 80 mm). </li><li> Ağız pipet, uygun ucu kullanılarak çekilen pipet aspiratör tüpün bir ucunu ve diş ile güvence, ağızda diğer ucunu yerleştirin. </li></ol></li><li> Steril cımbız kullanarak yumurtalıkların toplamak ve bir hücre kültürü petri kabı (35 mm x 10 mm) altında bırakılması. M2 1 mi, daha önce 37 ° C &#39;de dengelenmiş ile örtünve% 5 CO2 (Şekil 2). </li><li> Yavaşça M2 (Şekil 3) antral oosit serbest bırakmak için steril bir insülin şırınga iğnesi ile yumurtalıkların antral folikül delinme. </li><li> Yavaşça ağız folikül hücreleri ve diğer olası doku artıkları (Şekil 4A) kaldırmak ve daha sonra, daha önce (embriyo kültürü için uygun mineral yağ ile kaplanmış M2 küçük damla (20 ul) altındaki yerleştirilmeleri için dar bir Pasteur pipeti ile oosit Pipeti hazırlanmıştır; Şekil 4B). NOT: M2 çeşitli ve farklı damla ile sürekli pipetleme oosit zona pellucida bağlı tüm kümülüs hücreleri çıkarmak için önemlidir. Ortamın pH değişiklikleri önlemek için mümkün olduğunca çabuk bu adımı gerçekleştirin. </li></ol> Hoechst33342 4. antral Oositler Boyama NOT: Antral oositler SN (çevrili Nukleolus), NSN (Çekirdekçik çevrili değil) ya da ayırt edilebilirBaşka ara form olarak, Hoechst33342 ve supravital konsantrasyonu (veya bazlar için özel herhangi bir başka belirteçler AT) 14 boyandıktan sonra kendi kromatin organizasyonu dayalı. NSN dolayısıyla değil, adını yaparken aslında, SN oositlerin nucleolus etrafında Hoechst-pozitif halka göstermek. Doğru oosit boyama için: <ol><li> Karanlıkta 10 dakika boyunca 50 ng / ul supravital konsantrasyonda Hoechst33342 (20 ul) M2 seyreltildi damla bir ağız pipet kullanarak oosit aktarın. </li><li> Hoechst33342 ile inkübasyondan sonra, kromatin organizasyonu (SN ya SDİ) göre ayrılması için, mineral yağ ile kaplanmış M2 küçük damla (5 ul), alt kısmında bir ağız pipetle her bir oositin aktarın. Oosit kromatin yapılandırmasını görselleştirmek için Hoechst33342 filtresi (emisyon dalga boyu 486 nm) ile donatılmış herhangi bir floresan mikroskop kullanın. Not: kullanılan floresan mikroskop türüne bağlı olarak, it görüntü elde etmek için cam alt petri kullanmak zorunlu hale gelebilir. 35 mm çanak için numune tutucu ile donatılmış konfokal mikroskopi Olympus Fluoview Fv10i bir 0.17 mm standart kalınlıkta ve kabul edilebilir 0.13 0.21 mm aralığında olan görüntü elde etmek için tek cam alt-yemekler gerektirir. </li><li> Olasılıkla, daha uzun 5-10 saniye varlığı veya çekirdekçik etrafında bir halka yokluğu (Şekil 5) görselleştirmek için yeterli zaman oosit Heyecanlandırırmı. </li><li> In vitro olgunlaşmayı teşvik veya moleküler veya hücresel analizler için uygun tamponlar tutmak için% 5 CO 2 ve 37 ° C&#39;de M2, kültür antral SN ve NSN oosit sıralama sonra. </li></ol>

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The authors have nothing to disclose

Bu protokol yalıtmak ve fare antral GV oosit sınıflandırmak için kullanılan yöntem açıklanır. Birkaç istisna dışında, altını çizmek için özel bir kritik adımlar vardır. A) oosit canlılığını korumak ve b) kullanılan ortamda pH değişiklikleri önlemek: Birincisi: Bu prosedür mümkün olduğunca çabuk yapılmalıdır. İkincisi: oosit IVM ve IVF Aşağıdaki adımlar, özellikle kromatin hasar ve oosit sonraki ölümünü önlemek için Hoechst33342 (5-10 sn) kısaca heyecanlı olmalıdır. B...

Yumurtalık antral bölümünden izole antral tam olarak büyümüş oositler (GV, germinal vesicle) rutin gibi farklı amaçlar için kullanılabilir, örneğin, Metafaz II aşamaya kadar in vitro olgunlaşması arkasına moleküler ve hücresel mekanizmalar çalışma. Onların güzel bir görünüm en antral oosit rağmen ama hepsi değil, mayoz tamamlamak ve blastosist aşamasına ulaşabiliyorlar; döllenme 3-5 oluşursa aslında, insanlar 1,2 dahil olmak üzere birçok memeli türlerinde, içinde, bunların yaklaşık% 30, 2-hücreli aşamada kendi gelişimini tutuklama. Bugüne kadar, birkaç parametre bunu yapamaz olanlardan embriyo gelişimini sürdürmek mümkün oosit ayırt etmek için kullanılır. Örneğin, kresil mavi boyama (BCB) BCB + veya BCB- boyama ile ilgili olan bu sıralama yöntemi programı olmasına rağmen glikoz-6-fosfat dehidrojenaz aktivitesi göre oosit sıralamak için geçerli bir yöntemdirHala 6-8 bağımlı laboratuvar. Başka köklü yöntem kendi kromatin organizasyonu bulunur: (Hoechst33342 gibi) herhangi bir DNA interkalasyon boyalarla boyanmış ise, antral oosit% 70 çekirdekçik etrafında bir boya pozitif halka göstermek ve Nukleolus (SN) çevrili denir olan% 30 kalarak Bir daha benekli olumlu sinyaller ve (NSN) 3-5 değil çevrili Nukleolus denir. Son zamanlarda biz gösterdi sitoplazmik örgülerde 9 (CPLS, memeli oosit ve embriyoların hem maternal mRNA ve ribozomlar için önemli depolama siteleri) olmaması 10. ve varlığı ile birlikte (CPLS oluşumu 11 için gerekli) MATER aşağı-regülasyonu, Onların sitoplazmalarında 9,12 lipid damlacıkları, 2-hücre aşamasına ötesine devam etmek NSN oosit yetersizlik ile ilgili diğer nedenler olabilir. Ne yazık ki, bazı teknikler antral SN ve SDİ oosit ve sıralamak için uygulanabilir,Bu nedenle, (nükleer boyanma, tespit prosedürleri ya da ağız pipetler ile manipülasyon olmadan) daha az invazif yöntem geliştirilmesi hem insan ve hayvan embriyo gelişimi oranlarını artırmak için çok önemli hale gelebilir. Bu yazıda, detay, basit ve hızlı bir protokol reklam sıralama SN ve dişi farelerden alınan NSN antral oosit izole etmek için kullanılan ve kadın gametogenez, oosit olgunlaşması ve embriyo gelişimi çalışmasında ilgilenen tüm bilim adamlarına hitap etmektedir.

<table><tbody><tr><td>PMSG</td><td>Sigma</td><td>G4527</td><td></td></tr><tr><td>EmbrioMax M2</td><td>Millipore</td><td>MR-015-PD</td><td></td></tr><tr><td>Hoechst33342</td><td>Thermo Scientific</td><td>62249</td><td></td></tr><tr><td>Mineral Oil</td><td>Sigma</td><td>M8410</td><td></td></tr><tr><td>Cell Culture Dish 35mmx10mm</td><td>Corning</td><td>430165</td><td></td></tr><tr><td>&amp;micro;-Dish 35mm, high glass bottom</td><td>Ibidi</td><td>81158</td><td></td></tr><tr><td>Pipette Pasteur Borosilicate</td><td>Corning</td><td>7095D-9</td><td></td></tr><tr><td>Aspirator tube assemblies for calibrated micropillary pipettes</td><td>Sigma</td><td>A5177</td><td></td></tr></tbody></table>

isolation and characterization of mouse antral oocytes based on nucleolar chromatin organization

This protocol describes a simple and quick method to isolate and characterize mouse antral GV (Germinal Vesicle) oocytes as able (SN, Surrounded Nucleolus) or unable (NSN, Not Surrounded Nucleolus) to develop to the blastocyst stage after in vitro maturation (IVM) and in vitro fertilization (IVF). It makes use of Hoeschst33342 (or any other DNA intercalating dye) able to bind to the heterochromatin of the nucleolus showing a ring in the SN oocytes or not, like in the NSN oocytes. This represents the easiest and quickest way to sort both antral oocytes that can be eventually used for IVM or IVF procedures. 
Briefly, the protocol consists of the following steps: hormone injection to stimulate follicular growth; isolation of the oocytes at the GV stage from the antral compartment by puncturing the ovary with a sterile needle; preparation of thin glass pipettes for mouth pipetting of the oocytes; sorting of the oocytes with Hoechst33342 prepared at a supravital concentration; IVM, IVF or any other molecular/cellular analysis.
Unfortunately there are still few evidences to sort SN and NSN oocytes using less invasive techniques. If and once they will be identified, they could be potentially applied to human assisted reproductive technologies, although with several aspects that should be modified. To date, this technique has potential implications to dramatically increase IVM and IVF successful procedures in both endangered and species with economic interest.

Aşağıdaki resimler Hoechst33342 aracılığıyla Oositler &#39;sıralamaya pipetler hazırlanması başlayarak fare yumurtalıkların antral oosit izole etmek için kullanılan yöntemi göstermektedir. Bu yöntem, oldukça basit ve bir CO2 kuluçka makinesi, bir stereomikroskop ile Hoechst33342 gözlenmesi için doğru bir filtre ile donatılmış bir fluoresans mikroskopu ile donatılmış herhangi bir laboratuvar gerçekleştirilebilir Şekil 1 pipet haz...

Watch this Scientific Journal Video about Isolation and Characterization of Mouse Antral Oocytes Based on Nucleolar Chromatin Organization at JoVE.com

Isolation and Characterization of Mouse Antral Oocytes Based on Nucleolar Chromatin Organization

Burada Nükleolar organizasyon dayalı fare antral oosit karakterizasyonu için bir protokol mevcut.

Nucleolar Kromatin Teşkilatı dayanarak Fare Antral OOSİT İzolasyonu ve Karakterizasyonu

This protocol describes a simple and quick method to isolate and characterize mouse antral GV (Germinal Vesicle) oocytes as able (SN, Surrounded ...

isolation-characterization-mouse-antral-oocytes-based-on-nucleolar

Research

JoVE Journal

Developmental Biology

13.3K Görüntüleme.  Fondazione IRCCS Policlinico San Matteo.  Burada Nükleolar organizasyon dayalı fare antral oosit karakterizasyonu için bir protokol mevcut. 

Video: Isolation and Characterization of Mouse Antral Oocytes Based on Nucleolar Chromatin Organization

Chromatin Spread Preparations for the Analysis of Mouse Oocyte Progression from Prophase to Metaphase II

Chromatin spread techniques have been widely used to assess the dynamic localization of various proteins during gametogenesis, particularly for spermatogenesis. These techniques allow for visualization of protein and DNA localization patterns during meiotic events such as homologous chromosome pairing, synapsis and DNA repair. While a few protocols have been described in the literature, general chromatin spread techniques using mammalian prophase oocytes are limited and difficult due to the timing of meiosis initiation in fetal ovaries. In comparison, prophase spermatocytes can be collected from juvenile male mice with higher yields without the need for microdissection. However, it is difficult to obtain a pure synchronized population of cells at specific stages due to the heterogeneity of meiotic and post-meiotic germ cell populations in the juvenile and adult testis. For later stages of meiosis, it is advantageous to assess oocytes undergoing meiosis I (MI) or meiosis II (MII), because groups of mature oocytes can be collected from adult female mice and stimulated to resume meiosis in culture. Here, methods for meiotic chromatin spread preparations using oocytes dissected from fetal, neonatal and adult ovaries are described with accompanying video demonstrations. Chromosome missegregation events in mammalian oocytes are frequent, particularly during MI. These techniques can be used to assess and characterize the effects of different mutations or environmental exposures during various stages of oogenesis. As there are distinct differences between oogenesis and spermatogenesis, the techniques described within are invaluable to increase our understanding of mammalian oogenesis and the sexually dimorphic features of chromosome and protein dynamics during meiosis.

Oogenesis in mammals is known to be error-prone, particularly due to chromosome missegregation. This manuscript describes chromatin spread preparation methods for mouse prophase, metaphase I and II-staged oocytes. These fundamental techniques allow for the study of chromatin-bound proteins and chromosome morphology throughout mammalian oogenesis.

Kromatin fare oosit ilerleme profaz metafaz II analizi için hazırlıklar yaymak

Chromatin spread techniques have been widely used to assess the dynamic localization of various proteins during gametogenesis, particularly for ...

Genetik

Using Mouse Oocytes to Assess Human Gene Function During Meiosis I

Embryonic aneuploidy is the major genetic cause of infertility in humans. Most of these events originate during female meiosis, and albeit positively correlated with maternal age, age alone is not always predictive of the risk of generating an aneuploid embryo. Therefore, gene variants might account for incorrect chromosome segregation during oogenesis. Given that access to human oocytes is limited for research purposes, a series of assays were developed to study human gene function during meiosis I using mouse oocytes. First, messenger RNA (mRNA) of the gene and gene variant of interest are microinjected into prophase I-arrested mouse oocytes. After allowing time for expression, oocytes are synchronously released into meiotic maturation to complete meiosis I. By tagging the mRNA with a sequence of a fluorescent reporter, such as green fluorescent protein (Gfp), the localization of the human protein can be assessed in addition to the phenotypic alterations. For example, gain or loss of function can be investigated by establishing experimental conditions that challenge the gene product to fix meiotic errors. Although this system is advantageous in investigating human protein function during oogenesis, adequate interpretation of results should be undertaken given that protein expression is not at endogenous levels and, unless controlled for (i.e. knocked out or down), murine homologs are also present in the system.

As the genetic variants associated with human disease begin to become uncovered, it is becoming increasingly important to develop systems with which to rapidly evaluate the biological significance of those identified variants. This protocol describes methods for evaluating human gene function during female meiosis I using mouse oocytes.

Mayoz sırasında insan gen işlevini değerlendirmek için fare yumurta kullanarak ben

Embryonic aneuploidy is the major genetic cause of infertility in humans. Most of these events originate during female meiosis, and albeit positively ...

Analysis of Chromosome Segregation, Histone Acetylation, and Spindle Morphology in Horse Oocytes

The field of assisted reproduction has been developed to treat infertility in women, companion animals, and endangered species. In the horse, assisted reproduction also allows for the production of embryos from high performers without interrupting their sports career and contributes to an increase in the number of foals from mares of high genetic value. The present manuscript describes the procedures used for collecting immature and mature oocytes from horse ovaries using ovum pick-up (OPU). These oocytes were then used to investigate the incidence of aneuploidy by adapting a protocol previously developed in mice. Specifically, the chromosomes and the centromeres of metaphase II (MII) oocytes were fluorescently labeled and counted on sequential focal plans after confocal laser microscope scanning. This analysis revealed a higher incidence in the aneuploidy rate when immature oocytes were collected from the follicles and matured in vitro compared to in vivo. Immunostaining for tubulin and the acetylated form of histone four at specific lysine residues also revealed differences in the morphology of the meiotic spindle and in the global pattern of histone acetylation. Finally, the expression of mRNAs coding for histone deacetylases (HDACs) and acetyl-transferases (HATs) was investigated by reverse transcription and quantitative-PCR (q-PCR). No differences in the relative expression of transcripts were observed between in vitro and in vivo matured oocytes. In agreement with a general silencing of the transcriptional activity during oocyte maturation, the analysis of the total transcript amount can only reveal mRNA stability or degradation. Therefore, these findings indicate that other translational and post-translational regulations might be affected.
Overall, the present study describes an experimental approach to morphologically and biochemically characterize the horse oocyte, a cell type that is extremely challenging to study due to low sample availability. However, it can expand our knowledge on the reproductive biology and infertility in monovulatory species.

This manuscript describes an experimental approach to morphologically and biochemically characterize horse oocytes. Specifically, the present work illustrates how to collect immature and mature horse oocytes by ultrasound-guided ovum pick-up (OPU) and how to investigate chromosome segregation, spindle morphology, global histone acetylation, and mRNA expression.

At Oositlerinde Kromozom Ayrımı, Histon Asetilasyonu ve İşmili Morfolojisi Analizi

The field of assisted reproduction has been developed to treat infertility in women, companion animals, and endangered species. In the horse, assisted ...

Gelişim Biyolojisi

A Neural Network-Based Identification of Developmentally Competent or Incompetent Mouse Fully-Grown Oocytes

Infertility clinics would benefit from the ability to select developmentally competent vs. incompetent oocytes using non-invasive procedures, thus improving the overall pregnancy outcome. We recently developed a classification method based on microscopic live observations of mouse oocytes during their in vitro maturation from the germinal vesicle (GV) to the metaphase II stage, followed by the analysis of the cytoplasmic movements occurring during this time-lapse period. Here, we present detailed protocols of this procedure. Oocytes are isolated from fully-grown antral follicles and cultured for 15 h inside a microscope equipped for time-lapse analysis at 37 &#176;C and 5% CO2. Pictures are taken at 8 min intervals. The images are analyzed using the Particle Image Velocimetry (PIV) method that calculates, for each oocyte, the profile of Cytoplasmic Movement Velocities (CMVs) occurring throughout the culture period. Finally, the CMVs of each single oocyte are fed through a mathematical classification tool (Feed-forward Artificial Neural Network, FANN), which predicts the probability of a gamete to be developmentally competent or incompetent with an accuracy of 91.03%. This protocol, set up for the mouse, could now be tested on oocytes of other species, including humans.

Here, we present a protocol for non-invasive assessment of oocyte developmental competence performed during their in vitro maturation from the germinal vesicle to the metaphase II stage. This method combines time-lapse imaging with particle image velocimetry (PIV) and neural network analyses.

Bir Neural ağ tabanlı kimlik gelişimsel olarak yetkili veya yetersiz fare köklerin yumurta

Infertility clinics would benefit from the ability to select developmentally competent vs. incompetent oocytes using non-invasive procedures, thus ...

Ovarian Tissue Culture to Visualize Phenomena in Mouse Ovary

Mammalian females periodically ovulate an almost constant number of oocytes during each estrus cycle. To sustain such regularity and periodicity, regulation occurs at the hypothalamic-pituitary-gonadal axis level and on developing follicles in the ovary. Despite active studies, follicle development mechanisms are not clear because of the several steps involved from the dormant primordial follicle activation to ovulation, and because of the regulation complexity that differs at each follicular stage. To investigate the mechanisms of follicle development, and the dynamics of follicles throughout the estrus cycle, we developed a mouse ovarian tissue culture model that can be used to observe follicle development using a microscope. Systematic follicle development, periodical ovulation, and follicle atresia can all be reproduced in the cultured ovary model, and the culture conditions can be experimentally modulated. Here, we demonstrate the usefulness of this method in the study of the regulatory mechanisms of follicle development and other ovarian phenomena.

Ovarian tissue cultures can be used as models of follicle development, ovulation, and follicle atresia and indicate regulatory mechanisms of dynamic ovarian processes.

Mouse ovarium olayları görselleştirmek için yumurtalık doku kültürü

Mammalian females periodically ovulate an almost constant number of oocytes during each estrus cycle. To sustain such regularity and periodicity, ...

Multi-Photon Laser Ablation of Cytoplasmic Microtubule Organizing Centers in Mouse Oocytes

The fidelity of oocyte meiosis is critical for generating developmentally competent euploid eggs. In mammals, the oocyte undergoes a lengthy arrest at prophase I of the first meiotic division. After puberty and upon meiotic resumption, the nuclear membrane disassembles (nuclear envelope breakdown), and the spindle is assembled mainly at the oocyte center. Initial central spindle positioning is essential to protect against abnormal kinetochore-microtubule (MT) attachments and aneuploidy. The centrally positioned spindle migrates in a time-sensitive manner toward the cortex, and this is a necessary process to extrude a tiny polar body. In mitotic cells, spindle positioning relies on the interaction between centrosome-mediated astral MTs and the cell cortex. On the contrary, mouse oocytes lack classic centrosomes and, instead, contain numerous acentriolar MT organizing centers (MTOCs). At the metaphase I stage, mouse oocytes have two different sets of MTOCs: (1) MTOCs that are clustered and sorted to assemble spindle poles (polar MTOCs), and (2) metaphase cytoplasmic MTOCs (mcMTOCs) that remain in the cytoplasm and do not contribute directly to spindle formation but play a crucial role in regulating spindle positioning and timely spindle migration. Here, a multi-photon laser ablation method is described to selectively deplete endogenously labeled mcMTOCs in oocytes collected from Cep192-eGfp reporter mice. This method contributes to the understanding of the molecular mechanisms underlying spindle positioning and migration in mammalian oocytes.

An optimized protocol is presented that enables the depletion of cytoplasmic microtubule organizing centers in mouse oocytes during metaphase I using a near-infrared femtosecond laser.

Fare Oositlerinde Sitoplazmik Mikrotübül Düzenleme Merkezlerinin Multi-Foton Lazer Ablasyonu

The fidelity of oocyte meiosis is critical for generating developmentally competent euploid eggs. In mammals, the oocyte undergoes a lengthy arrest at ...

Farelerin Profaz Tutuklu Oositlerinde DNA Hasarının Belirlenmesi

Detection of DNA Double-Stranded Breaks in Mouse Oocytes

Oocytes are amongst the biggest and most long-lived cells in the female body. They are formed in the ovaries during embryonic development and remain arrested at the prophase of meiosis I. The quiescent state may last for years until the oocytes receive a stimulus to grow and obtain the competency to resume meiosis. This protracted state of arrest makes them extremely susceptible to accumulating DNA-damaging insults, which affect the genetic integrity of the female gametes and, therefore, the genetic integrity of the future embryo. 
Consequently, the development of an accurate method to detect DNA damage, which is the first step for the establishment of DNA damage response mechanisms, is of vital importance. This paper describes a common protocol to test the presence and progress of DNA damage in prophase-arrested oocytes during a period of 20 h. Specifically, we dissect mouse ovaries, retrieve the cumulus-oocyte complexes (COCs), remove the cumulus cells from the COCs, and culture the oocytes in &#924;2 medium containing 3-isobutyl-1-methylxanthine to maintain the state of arrest. Thereafter, the oocytes are treated with the cytotoxic, antineoplasmic drug, etoposide, to engender double-strand breaks (DSBs). 
By using immunofluorescence and confocal microscopy, we detect and quantify the levels of the core protein &#947;H2AX, which is the phosphorylated form of the histone H2AX. H2AX becomes phosphorylated at the sites of DSBs after DNA damage. The inability to restore DNA integrity following DNA damage in oocytes can lead to infertility, birth defects, and increased rates of spontaneous abortions. Therefore, the understanding of DNA damage response mechanisms and, at the same time, the establishment of an intact method for studying these mechanisms are essential for reproductive biology research.

Yazar Spotlight: Memeli Oositlerinde ve Preimplantasyon Embriyolarında DNA Hasar Tepkisini Anlamak 

Maintaining oocyte genome integrity is necessary to ensure the genetic fidelity in the resulting embryo. Here, we present an accurate protocol for detecting DNA double-strand breaks in mammalian female germ cells.

Fare Oositlerinde DNA Çift Sarmallı Kırılmaların Tespiti

Oocytes are amongst the biggest and most long-lived cells in the female body. They are formed in the ovaries during embryonic development and remain ...

Mouse Oocyte Microinjection, Maturation and Ploidy Assessment

Mistakes in chromosome segregation lead to aneuploid cells. In somatic cells, aneuploidy is associated with cancer but in gametes, aneuploidy leads to infertility, miscarriages or developmental disorders like Down syndrome. Haploid gametes form through species-specific developmental programs that are coupled to meiosis. The first meiotic division (MI) is unique to meiosis because sister chromatids remain attached while homologous chromosomes are segregated. For reasons not fully understood, this reductional division is prone to errors and is more commonly the source of aneuploidy than errors in meiosis II (MII) or than errors in male meiosis 1,2. 
In mammals, oocytes arrest at prophase of MI with a large, intact germinal vesicle (GV; nucleus) and only resume meiosis when they receive ovulatory cues. Once meiosis resumes, oocytes complete MI and undergo an asymmetric cell division, arresting again at metaphase of MII. Eggs will not complete MII until they are fertilized by sperm. Oocytes also can undergo meiotic maturation using established in vitro culture conditions 3. Because generation of transgenic and gene-targeted mouse mutants is costly and can take long periods of time, manipulation of female gametes in vitro is a more economical and time-saving strategy. 
Here, we describe methods to isolate prophase-arrested oocytes from mice and for microinjection. Any material of choice may be introduced into the oocyte, but because meiotically-competent oocytes are transcriptionally silent 4,5 cRNA, and not DNA, must be injected for ectopic expression studies. To assess ploidy, we describe our conditions for in vitro maturation of oocytes to MII eggs. Historically, chromosome-spreading techniques are used for counting chromosome number 6. This method is technically challenging and is limited to only identifying hyperploidies. Here, we describe a method to determine hypo-and hyperploidies using intact eggs 7-8. This method uses monastrol, a kinesin-5 inhibitor, that collapses the bipolar spindle into a monopolar spindle 9 thus separating chromosomes such that individual kinetochores can readily be detected and counted by using an anti-CREST autoimmune serum. Because this method is performed in intact eggs, chromosomes are not lost due to operator error.

Oocytes are prone to aneuploidy due to errors in chromosome segregation during meiotic maturation. Aneuploid eggs can cause infertility, miscarriages or developmental disorders like Down syndrome. Here, we describe methods to introduce materials of choice into oocytes and methods to study meiotic maturation and assess ploidy.

Fare Oosit Mikroenjeksiyon, olgunlaşması ve ploidi Değerlendirmesi

Mistakes in chromosome segregation lead to aneuploid cells.  In somatic cells, aneuploidy is associated with cancer but in gametes, aneuploidy leads to ...

Nucleolar Kromatin Teşkilatı dayanarak Fare Antral OOSİT İzolasyonu ve Karakterizasyonu

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Kromatin fare oosit ilerleme profaz metafaz II analizi için hazırlıklar yaymak

Mayoz sırasında insan gen işlevini değerlendirmek için fare yumurta kullanarak ben

At Oositlerinde Kromozom Ayrımı, Histon Asetilasyonu ve İşmili Morfolojisi Analizi

Bir Neural ağ tabanlı kimlik gelişimsel olarak yetkili veya yetersiz fare köklerin yumurta

Mouse ovarium olayları görselleştirmek için yumurtalık doku kültürü

Fare Oositlerinde Sitoplazmik Mikrotübül Düzenleme Merkezlerinin Multi-Foton Lazer Ablasyonu

Fare Oositlerinde DNA Çift Sarmallı Kırılmaların Tespiti

Fare Oositlerinde DNA Çift Sarmallı Kırılmaların Tespiti

Fare Oositlerinde DNA Çift Sarmallı Kırılmaların Tespiti

Fare Oosit Mikroenjeksiyon, olgunlaşması ve ploidi Değerlendirmesi