Identification of Drosophila and Human 7-Methyl GMP-specific Nucleotidases
Notice bibliographique
Résumé
Turnover of mRNA releases, in addition to the four regular nucleoside monophosphates, the methylated cap nucleotide in the form of 7-methylguanosine monophosphate (m7GMP) or diphosphate (m7GDP). The existence of pathways to eliminate the modified nucleotide seems likely, as its incorporation into nucleic acids is undesirable. Here we describe a novel 5′ nucleotidase from Drosophila that cleaves m7GMP to 7-methylguanosine and inorganic phosphate. The enzyme, encoded by the predicted gene CG3362, also efficiently dephosphorylates CMP, although with lower apparent affinity; UMP and the purine nucleotides are poor substrates. The enzyme is inhibited by elevated concentrations of AMP and also cleaves m7GDP to the nucleoside and two inorganic phosphates, albeit less efficiently. CG3362 has equivalent sequence similarity to two human enzymes, cytosolic nucleotidase III (cNIII) and the previously uncharacterized cytosolic nucleotidase III-like (cNIII-like). We show that cNIII-like also displays 5′ nucleotidase activity with a high affinity for m7GMP. CMP is a slightly better substrate but again with a higher Km. The activity of cNIII-like is stimulated by phosphate. In contrast to cNIII-like, cNIII and human cytosolic nucleotidase II do not accept m7GMP as a substrate. We suggest that the m7G-specific nucleotidases protect cells against undesired salvage of m7GMP and its incorporation into nucleic acids.Background: mRNA decay releases, in addition to the regular nucleotides, 7-methyl GMP derived from the 5′ cap.Results: We describe new members of the 5′ nucleotidase family degrading 7-methyl GMP to 7-methylguanosine and orthophosphate.Conclusion: Cells have mechanisms to prevent potential salvage of 7-methyl GMP.Significance: 7-Methyl GMP degradation may be important to prevent its incorporation into nucleic acids. Turnover of mRNA releases, in addition to the four regular nucleoside monophosphates, the methylated cap nucleotide in the form of 7-methylguanosine monophosphate (m7GMP) or diphosphate (m7GDP). The existence of pathways to eliminate the modified nucleotide seems likely, as its incorporation into nucleic acids is undesirable. Here we describe a novel 5′ nucleotidase from Drosophila that cleaves m7GMP to 7-methylguanosine and inorganic phosphate. The enzyme, encoded by the predicted gene CG3362, also efficiently dephosphorylates CMP, although with lower apparent affinity; UMP and the purine nucleotides are poor substrates. The enzyme is inhibited by elevated concentrations of AMP and also cleaves m7GDP to the nucleoside and two inorganic phosphates, albeit less efficiently. CG3362 has equivalent sequence similarity to two human enzymes, cytosolic nucleotidase III (cNIII) and the previously uncharacterized cytosolic nucleotidase III-like (cNIII-like). We show that cNIII-like also displays 5′ nucleotidase activity with a high affinity for m7GMP. CMP is a slightly better substrate but again with a higher Km. The activity of cNIII-like is stimulated by phosphate. In contrast to cNIII-like, cNIII and human cytosolic nucleotidase II do not accept m7GMP as a substrate. We suggest that the m7G-specific nucleotidases protect cells against undesired salvage of m7GMP and its incorporation into nucleic acids. Background: mRNA decay releases, in addition to the regular nucleotides, 7-methyl GMP derived from the 5′ cap. Results: We describe new members of the 5′ nucleotidase family degrading 7-methyl GMP to 7-methylguanosine and orthophosphate. Conclusion: Cells have mechanisms to prevent potential salvage of 7-methyl GMP. Significance: 7-Methyl GMP degradation may be important to prevent its incorporation into nucleic acids.
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 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 | 0,000 | 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 | 0,000 | 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 ».