Characterization of the «Smpec» Knock-out mouse
Notice bibliographique
Résumé
The Smpec gene is expressed solely in the chondrocytes at the resting and proliferating zones but not in the hypertrophic chondrocytes. The SMPEC protein is a chondroitin sulfate proteoglycan (CS PG) composed of 121 amino acids. In silico analysis suggests it is a transmembrane protein. The purpose of this study was to characterize the Smpec knockout (KO) mouse and identify its role in skeletogenesis in vivo. To confirm the suggested topology for the SMPEC protein, immunofluorescence (IF) was performed on 4 days post natal (P4) distal femur. The protein was localized to the cell surface of resting and proliferating chondrocytes, but also accumulated in intercolumnar septum of hypertrophic chondrocytes, suggesting its shed. Alcian blue /alizarin red staining, which stains cartilage and bone respectively, was performed on arms of P4 wild-type (WT) and KO mice and there were no qualitative differences in staining intensity neither in bone nor in cartilage of KO compared to WT. However, quantitative measurement indicated that the humeri were all statistically reduced in length by 10.4% in the KO compared to the WT. As it is wellknown that the longitudinal growth of long bones is mediated through the growth plate, thereby we focused our study on this region. Safranin O/Fast green staining in P4 distal femur revealed that the chondrocyte cell density of the resting and proliferating zones appeared less in the KO than in WT littermates. Quantitative analysis confirmed the hypocellularity of these zones. However, the thickness of the hypertrophic zone was normal. The expression profile of genes known to be important in skeletogenesis and mineralization was assessed by real-time qPCR. No statistically significant changes were detected in the Smpec KO as compared to WT at the three ages analyzed (day 4, day 28 and12 months). Similarly, primary chondrocytes cultures established from KO and WT rib cages, did not present any significant changes in expression of Col2a1, Col10a1, Sox9, and Acan. Furthermore, in such cultures, extracellular matrix deposition of proteoglycanaggrecan as assessed by alcian blue staining, was not significantly altered, indicating similarity in the metabolic activity of the chondrocytes. This indicates for the first time that loss of Smpec results in mild dwarfism in mice and that its function cannot be compensated by other genes at least at neonatal ages. The mechanism by which the lack of SMPEC causes dwarfism is still unclear.
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) | 0,001 | 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 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 ».