Differential regulation of abundance and deadenylation of maternal transcripts during bovine oocyte maturation in vitro and in vivo

<p>Abstract</p> <p>Background</p> <p>In bovine maturing oocytes and cleavage stage embryos, gene expression is mostly controlled at the post-transcriptional level, through degradation and deadenylation/polyadenylation. We have investigated how post transcriptional control of maternal transcripts was affected during in vitro and in vivo maturation, as a model of differential developmental competence.</p> <p>Results</p> <p>Using real time PCR, we have analyzed variation of maternal transcripts, in terms of abundance and polyadenylation, during in vitro or in vivo oocyte maturation and in vitro embryo development. Four genes are characterized here for the first time in bovine: ring finger protein 18 (<it>RNF18</it>) and breast cancer anti-estrogen resistance 4 (<it>BCAR4</it>), whose oocyte preferential expression was not previously reported in any species, as well as Maternal embryonic leucine zipper kinase (<it>MELK</it>) and <it>STELLA</it>. We included three known oocyte marker genes (Maternal antigen that embryos require (<it>MATER</it>), Zygote arrest 1 (<it>ZAR1</it>), NACHT, leucine rich repeat and PYD containing 9 (<it>NALP9</it>)). In addition, we selected transcripts previously identified as differentially regulated during maturation, peroxiredoxin 1 and 2 (<it>PRDX1, PRDX2</it>), inhibitor of DNA binding 2 and 3 (<it>ID2</it>, <it>ID3</it>), cyclin B1 (<it>CCNB1</it>), cell division cycle 2 (<it>CDC2</it>), as well as Aurora A (<it>AURKA</it>). Most transcripts underwent a moderate degradation during maturation. But they displayed sharply contrasted deadenylation patterns that account for variations observed previously by DNA array and correlated with the presence of a putative cytoplasmic polyadenylation element in their 3' untranslated region. Similar variations in abundance and polyadenylation status were observed during in vitro maturation or in vivo maturation, except for <it>PRDX1</it>, that appears as a marker of in vivo maturation. Throughout in vitro development, oocyte restricted transcripts were progressively degraded until the morula stage, except for <it>MELK </it>; and the corresponding genes remained silent after major embryonic genome activation.</p> <p>Conclusion</p> <p>Altogether, our data emphasize the extent of post-transcriptional regulation during oocyte maturation. They do not evidence a general alteration of this phenomenon after in vitro maturation as compared to in vivo maturation, but indicate that some individual messenger RNA can be affected.</p

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

Cytoplasmic polyadenylation and deadenylation during in vitro maturation of bovine oocytes

Lors de la maturation de l'ovocyte la transcription s'arrête précocement autour de la rupture de la vésicule germinale, et l'expression génique est essentiellement contrôlée au niveau post-transcriptionnel. Parmi les systèmes de régulation post-transcriptionnels, les polyadénylation et déadénylation cytoplasmiques jouent un rôle fondamental. Nous avons étudié les changements d'adénylation de transcrits spécifiques pendant la maturation in vitro des ovocytes bovins, en utilisant la Rapid Amplification of cDNA Ends-Poly Adenylation Test (RACE-PAT), une technique spécifiquement conçue pour estimer la longueur des queues poly(A). Dans une première partie, le statut de polyadénylation des cyclines A2 et B1 a été étudié. Un allongement irrégulier de la queue poly(A) est observé après maturation pour l'ARNm de la cycline A2. Dans le cas de la cycline B1, une élongation importante se produit pendant les premières 12h de maturation. Cette polyadénylation cytoplasmique a été mise en rapport dans plusieurs espèces avec une traduction de la protéine, ayant lieu peu avant que la maturation ovocytaire atteigne le stade de métaphase I. L'utilisation de l'inhibiteur spécifique de polyadénylation cordycepin (3'-dA) en parallèle avec un inhibiteur de transcription (3'-dG), nous a permis de démontrer que dans nos conditions de maturation (en présence d'Epidermal Growth Factor et en absence de gonadotropines) la polyadénylation est indispensable à la progression méiotique, alors que la transcription ne l'est pas. Nous avons ensuite analysé le statut d'adénylation de la Peroxyrédoxine 6 (PRDX6) et du Growth and Differentiation Factor-9 (GDF-9), deux facteurs qui semblent jouer un rôle durant la maturation. Ces deux transcrits sont déadenylés pendant la maturation in vitro. La déadénylation observée pour PRDX6 est graduelle et progressive tout au long du processus de maturation, tandis que celle observée pour GDF-9 est plus tardive, plus abrupte, et plus prononcée. L'analyse des régions 3' non codantes des deux transcrits a montré la présence de séquences régulatrices de la polyadénylation cytoplasmique et de la déadénylation, ce qui suggère que la déadénylation observée est régulée et ne ferait donc pas partie de la vague massive de déadénylation par défaut qui a lieu lors de la maturation ovocytaire. Nos résultats montrent que les quatre transcrits analysés sont soumis à une polyadénylation ou une déadénylation spécifique pendant la maturation ovocytaire, et soulignent l'importance de la polyadénylation dans le contrôle de la méiose. ...A transcriptionally-dormant period is characteristic of oocyte maturation, where transcription is silenced around the germinal vesicle breakdown (GVBD), and gene expression is essentially regulated at the post-transcriptional level. Among post-transcriptional regulation systems, cytoplasmic polyadenylation and deadenylation play a fundamental role. To assess the importance of polyadenylation control during oocyte maturation we studied the polyadenylation status changes of specific transcripts, during in vitro maturation of bovine oocytes. We used Rapid Amplification of cDNA Ends-Polyadenylation Test (RACE-PAT), a technique specifically designed to estimate poly(A) tail lentghs. In a first part, we analysed the polyadenylation status of cyclins A2 and B1. We found an inconstant elongation of the poly(A) tail after maturation for the cyclin A2 mRNA, while an important elongation was observed for cyclin B1, occurring during the first 12h of maturation. This cytoplasmic polyadenylation has been related to translation of the protein in several species, occurring shortly before oocyte maturation reaches the metaphase I stage. We also used a specific inhibitor of polyadenylation (cordycepin, 3'-dA) in parallel with a transcription inhibitor (3'-dG), that allowed us to demonstrate that in our maturation conditions (in presence of Epidermal Growth Factor and absence of gonadotropins) polyadenylation is essential for meiotic progression, while transcription is not necessary. Then, we analysed the adenylation status of Peroxiredoxin 6 (PRDX6) and Growth and Differentiation Factor-9 (GDF-9), two factors that would play a role during maturation, and found that both transcripts are deadenylated during the in vitro maturation process. The deadenylation observed for PRDX-6 was gradual and progressive along the maturation process. On the other hand, deadenylation in the GDF-9 mRNA was more abrupt and pronounced, taking place at the end of the maturation period. The analysis of the 3'-untranslated regions (3'UTRs) of both transcripts showed the presence of regulatory sequences involved in the control of cytoplasmic polyadenylation and deadenylation. This would suggest that the deadenylation observed is regulated, and not part of the default deadenylation process occurring in oocytes during maturation. Our results show that polyadenylation or deadenylation specific to each transcript occurs in the four transcripts analyzed during maturation in this work, and strengthen as well the importance of polyadenylation in the control of meiosis.Doctorat en sciences (sciences biologiques) (BIOL 3)--UCL, 200

Revisitando a Florence Nightingale desde una perspectiva de género

En 2010 conmemoramos el centenario de la muerte de Florence Nightingale. En la época en la que vivió, la situación de la mujer era difícil con un ideal de feminidad que imponía su exclusión de la vida pública y laboral, reservada al varón; a pesar de esta situación social Nightingale fue una figura destacada, entre sus méritos destacan la demostración de la importancia que otras ciencias, como la estadística, proporcionaban para controlar, aprender y mejorar la asistencia hospitalaria. Fue pionera en la recogida, almacenamiento y uso de la información para analizar y gestionar la atención al paciente; precursora de una informática sanitaria sostenible y ubicua. Florence modeló una nueva profesión para las mujeres extraída de siglos de ignorancia y superstición

Maternally inherited npm2 mRNA is crucial for egg developmental competence in zebrafish.

International audienceThe molecular mechanisms underlying and determining egg developmental competence remain poorly understood in vertebrates. Nucleoplasmin (Npm2) is one of the few known maternal effect genes in mammals, but this maternal effect has never been demonstrated in nonmammalian species. A link between developmental competence and the abundance of npm2 maternal mRNA in the egg was previously established using a teleost fish model for egg quality. The importance of maternal npm2 mRNA for egg developmental competence remains unknown in any vertebrate species. In the present study, we aimed to characterize the contribution of npm2 maternal mRNA to early developmental success in zebrafish using a knockdown strategy. We report here the oocyte-specific expression of npm2 and maternal inheritance of npm2 mRNA in zebrafish eggs. The knockdown of the protein translated from this maternal mRNA results in developmental arrest before the onset of epiboly and subsequent embryonic death, a phenotype also observed in embryos lacking zygotic transcription. Npm2 knockdown also results in impaired transcription of the first-wave zygotic genes. Our results show that npm2 is also a maternal effect gene in a nonmammalian vertebrate species and that maternally inherited npm2 mRNA is crucial for egg developmental competence. We also show that de novo protein synthesis from npm2 maternal mRNA is critical for developmental success beyond the blastula stage and required for zygotic genome activation. Finally, our results suggest that npm2 maternal mRNA is an important molecular factor of egg quality in fish and possibly in all vertebrates

Molecular mechanisms controlling egg quality

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The molecular basis of oocyte competence in fish

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Mieux comprendre ce qui fait un oeuf de bonne qualité

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Factors affecting oocyte quality: who is driving the follicle?

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