253 BOVINE OOCYTE CYCLIN B1 MRNA UNDERGOES CYTOPLASMICPOLYADENYLATION BEFORE THE BEGINNING OF IN VITRO MATURATION
Notice bibliographique
Résumé
Maternal oocyte Cyclin B1 mRNA is known to be stored in the cytoplasm with a short poly(A) tail and be translationally dormant at GV stage. During maturation, Cyclin B1 poly(A) tail is elongated by a process called cytoplasmic polyadenylation and driven by A/U-rich cis-acting elements in its 3' untranslated region (UTR) known as cytoplasmic polyadenylation elements (CPEs). The objective of this study was to elucidate whether GV-stage bovine oocytes possess a stockpile of Cyclin B1 mRNA stored with a short a poly(A) tail that is elongated during maturation by CPE regulation. The mRNA poly(A) tail length was measured by Rapid Amplification of cDNA Ends Polyadenylation test (Race-PAT) on oocytes (n = 100) at the GV stage and 3, 5, 8, 10, 15, 20, and 25 h of in vitro maturation. The mRNA poly(A) tail length was also measured in triplicate (n = 20) on cold oocytes in GV (all manipulations on ice), warm oocytes in GV (ovaries transported in warm saline and manipulations on ice) and warm + 2 h 30 min oocytes in GV (oocytes left for an additional 2 h and 30 min at room temperature). To assess for variation in mRNA quantity, Cyclin B1 mRNA level was quantified by real-time PCR (Lightcycler, Roche, Indianapolis, IN, USA) in cold, warm or warm + 2 h 30 min GV oocytes (n = 20). The data were treated as factorial design, using treatment and type of RT as factors, and analysed by ANOVA (SAS Inst., Cary, NC, USA). Differences between means were checked using Tukey’s test. Oocyte Cyclin B1 transcript show two different 3' UTRs. These transcripts had the same ORF but different 3' UTR lengths because of an alternative nuclear polyadenylation element AAUAAA (NPE). The longest form (Cyclin B1L) that possessed a putative CPE (UUUUAAUAAA) fused to the last NPE was studied. In warm GV oocytes, Cyclin B1L had a long poly(A) tail of 100 adenosine residues, and this length did not change during in vitro maturation. Interestingly, we found that Cyclin B1L showed an expected short poly(A) tail when the ovaries and the oocytes were transported and manipulated on ice. We showed that Cyclin B1L mRNA is cytoplasmically polyadenylated (addition of 75 adenosine residues) between the time of collection and the end of manipulation. This lengthening is most probably sufficient to promote translation. There was no significant difference between the Cyclin B1 mRNA quantity of cold oocytes or warm oocytes when the oligo used for the reverse transcription was either dt or decamers. Therefore, we believe that the increase in poly(A) tail length is not the result of Cyclin B1L mRNA degradation in cold oocytes or de novo transcription in warm oocytes. We report for the first time that Cyclin B1L cytoplasmic polyadenylation is carried out well before the beginning of in vitro maturation in bovine oocytes when ovaries are transported from the slaughterhouse in warm saline. Studying the real early mechanisms leading to resumption of meiosis in bovine oocytes is complicated by Cyclin B1 polyadenylation occurring prior to in vitro maturation. (Supported by NSERC.)
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,001 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,002 | 0,001 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».