CRISPR-Cas9-mediated knockout of GCN2 reveals a critical role in sensing amino acid deprivation in bovine mammary epithelial cells
Notice bibliographique
Résumé
The objective of this study was to determine the role of GCN2 in the response to AA deprivation of primary bovine mammary epithelial cells (BMEC). Cells were isolated from the mammary tissue of 2 lactating Holstein cows by enzymatic digestion, expanded, and induced to differentiate for 5 to 7 d. Relative mRNA expression was measured by real-time quantitative PCR. Protein abundance and site-specific phosphorylation were measured by immunoblotting. Knockout of GCN2 in BMEC was accomplished by lentiviral delivery of a targeted single guide RNA and endonuclease Cas9. To investigate the role of GCN2, we treated lactogenic differentiated BMEC with either culture medium lacking Arg, Leu, and Lys combined or lacking only one of the 3 AA of interest, in comparison to a control with a full complement of AA. Activation of GCN2 was inferred by the phosphorylation status of its downstream target eIF2α Ser51. We found that GCN2 was activated by both the deprivation of Arg, Leu, and Lys combined and of Arg alone, as shown by a 2.73- and 2.82-fold increase in phosphorylated eIF2α Ser51 after 1 h of deprivation, respectively. In addition, activation of GCN2 as measured by increased phosphorylation of eIF2α Ser51 during the deprivation of Arg, Leu, and Lys combined and of Arg alone was sustained for up to 8 h of deprivation. Phosphorylated eIF2α selectively upregulates translation of transcription factor ATF4, among others, during AA deprivation, which then targets genes necessary for restoring AA homeostasis. Therefore, we investigated the expression of ATF4 transcriptional targets, AA enzyme ASNS and AA transporters SLC7A1 and SLC38A2. We found that ASNS was upregulated in response to combined AA deprivation and by Arg deprivation alone by 3.6- and 4.51-fold, respectively, at 24 h of treatment. We found that SLC7A1 was upregulated in response to combined AA deprivation and deprivation of Arg alone by 2.0- and 2.36-fold, respectively, at 8 h of treatment. To establish the role of GCN2 (encoded by EIF2AK4) in the response to AA deprivation, we ablated GCN2 in BMEC using clustered regularly interspaced short palindromic repeats-Cas9. We showed that BMEC transduced with single guide RNA targeting EIF2AK4 were not as responsive to combined AA deprivation, compared with BMEC transduced with nontargeting single guide RNA. Taken together, our results demonstrate a critical role for GCN2 in sensing AA deprivation in BMEC.
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Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,001 |
| 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 | 0,000 | 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) | 0,000 | 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 tête enseignante, 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 ».