Identification of Several Connexins Expressed in Porcine Cumulus Oocyte Complex and Their Transcriptional Regulation During the First Hours of In Vitro Maturation.
Notice bibliographique
Résumé
Gap junction intercellular communication (GJC) plays an important role in ovarian cell physiology. Closure of GJC in the cumulus oocyte complex has been proposed to be involved in oocyte maturation, particularly in the resumption of meiosis, by controlling the flow of meiosis inhibitors such as cAMP and cGMP. GJC results from mutual docking of plasma membrane hemi-channels composed of six proteins subunits called connexins (Cx). GJC consist of one or more types of connexin, which interact with each other to form homomeric channels (composed of the same sort of Cx) or heteromeric channels (composed of different sort of Cx). The ability of the cell to vary gap junction structure in this manner increases the possibilities for regulating specific permeability. We have previously shown that cumulus cells are crucial during the first 4 hours of porcine in vitro maturation, driving meiotic resumption, and that GJC between cumulus cells is highly regulated by gonadotropins during this time period. Based on these results, we hypothesized that several connexins are expressed in the porcine cumulus oocyte complex to regulate GJC and that expression of these connexins is directed by gonadotropins during the first few hours of in vitro maturation. We first use a classic PCR approach to identified connexins expressed into the cumulus oocyte complex and localized their main expression in the oocyte or cumulus cells. We show that Cx43, Cx45 and Cx60 transcripts are present in the porcine cumulus oocyte complex while Cx26 and Cx32 are weakly expressed and we were not able to find any transcript of Cx37 or Cx30.3. We found that Cx60 is expressed in the oocyte, Cx43 in cumulus cells and Cx45 is expressed both in cumulus cells and the oocyte. Then, we used real time PCR to address whether or not expression of these connexins were regulated by gonadotropins during the first hours of maturation. We show that pregnant mare serum gonadotropin (PMSG) and human chorionic gonadotropin (hCG) acted in concert to increase by almost four times Cx43 transcripts in cumulus cells after 4.5h of maturation. Neither PMSG nor hCG alone in the culture medium were able to reproduce an increase in Cx43 expression. In contrast, expression of Cx45 and Cx60 is halved during the first hours of maturation. These results support that Cx43 is expressed in cumulus cells, Cx60 in the oocyte and Cx45 in both. Gonadotropins regulate the expression of these connexins during the first few hours of in vitro maturation. PMSG and hCG act together on cumulus cells to increase Cx43 expression after 4.5 hours of maturation whereas expression of Cx45 and Cx60 decreased. These findings improve our efforts to decipher the regulation of GJC during in vitro maturation and thus oocyte maturation. This study provides evidence that the composition of the IVM medium in terms of gonadotropins clearly affects connexins expression, which may in turn affect meiotic resumption and consequently the development of a competent oocyte.
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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 | 0,001 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 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) | 0,001 | 0,000 |
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 ».