189 TRANSCRIPTIONAL PROFILING OF HISTONE-MODIFYING GENES DURING BOVINE PRE-IMPLANTATION EMBRYO DEVELOPMENT IN VITRO
Notice bibliographique
Résumé
The proper removal of gametic epigenetic marks and coordinated re-establishment of the epigenome is critical to mammalian embryonic development. This global reprogramming of the embryonic genome includes fluctuations in both DNA methylation and histone modifications that are necessary to control chromatin structure and thus gene expression. In the bovine model, epigenetic changes occur from fertilization through blastocyst stages; in particular, and concurrent with the maternal-embryonic transition, de novo DNA methylation begins at the 8-cell stage. In order to understand which factors might be playing key roles in this epigenetic process, we used quantitative real-time PCR to characterize the temporal expression profiles of several genes involved in DNA and/or histone methylation: G9a, SetB1, Suv39h1, Suv420h1, SmyD3, Suz12, and LSH. Bovine ova and embryos were produced via in vitro maturation, fertilization, and culture from multiple pools of ova. Groups of 12–25 bovine ova or embryos, pooled at the 2-, 4 to 7-, mid 8-, late 8-, 12 to 16-cell, morula, and blastocyst stages, were washed twice through 1X PBS and stored in RNA lysis buffer at –80°C until further use. RNA was isolated from each sample using the RNeasy® Mini kit (Qiagen, Valencia, CA, USA), optimized for isolating RNA from single embryos, and treated to remove any contaminating genomic DNA. cDNA was generated with iScript™ reverse transcriptase (Bio-Rad Laboratories, Hercules, CA, USA) and diluted 1:10 with RNase/DNase-free water for further use in real-time PCR. Relative gene expression from each RNA sample was calculated in triplicate using the SYBR Green comparative Ct method (Applied Biosystems, Foster City, CA, USA) adjusted for individual PCR efficiencies (Bustin 2003) and normalized to the geometric mean Ct of 3 endogenous controls (GAPDH, YWHAZ, and SDHA) in order to account for differences in both cell number and amount of total mRNA present in each sample (Goossens et al. 2005). G9a and SetB1, both lysine-specific methyltransferases, were expressed at their highest levels in the metaphase II (MII) oocyte and 2-cell stage, before expression decreased gradually to basal levels by the morula and blastocyst stages. Suv39h1, Suv420h1, and SmyD3, also lysine-specific methyltransferases, all shared a similar pattern of expression: transcript levels were fairly high in the MII oocyte, increased at the 2-cell stage, then gradually dropped off around the 8–16-cell stage to basal levels by the morula stage. Interestingly, Suz12 and LSH both showed low expression from the MII oocyte until the 4 to 7-cell stage, increased dramatically at the 8-cell stage, then decreased again by the morula stage. Suz12 is a member of several Polycomb group complexes (PRCs); LSH associates with PRC-mediated gene silencing as well as DNMT3a and 3b. These data suggest that Suz12 and LSH may be implicated in bovine embryonic genome activation, while the latter genes are active during earlier cleavage events. Ongoing studies will evaluate the role of each of these epigenetic modifiers in bovine pre-implantation embryos by selective silencing via RNA interference.
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 | 0,001 |
| 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 | 0,001 |
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 ».