Rebooting the Zahnreihen: Analysis of the Jaw‐wide Patterning cues in the Adult Gecko Dentition
Notice bibliographique
Résumé
Unlike mammals, it is common for reptiles to replace their teeth throughout life. Through exploring the mechanisms of tooth replacement, particularly in adult reptiles we will learn about the cells and molecules that are required for the regeneration of the dentition. Wholemount preparations, x-rays and μCT scans of most lizards show that each functional tooth appears to line up with a series of unerupted teeth that are in progressively less mature stages of development going posteriorly (Zahnreihen). The position of the Zahnreihen is at approximately 147° to the jaw margin. The next teeth that are fated to replace a functional tooth do not appear in the mouth until they have reached a threshold size and have moved into position. It has been hypothesized that the unerupted teeth secrete factors that regulate the pace of tooth formation and spacing. All unerupted teeth are connected to each other via a dental lamina that extends around the jaw, extending deep into the soft tissue lingual to the functional teeth. Using an unbiased, surgical approach we asked whether there were signals emanating from the unerupted teeth and dental lamina. We carried out 4 types of surgeries in defined regions: enucleation of unerupted teeth with minimal disruption of the dental lamina, enucleation plus scrambling of the dental lamina, enucleation plus chemical cauterization of remaining epithelium or a sham control. Animals were analyzed at 7d, 14d, or 1–8 months. The macroscopic and microscopic phenotypes confirmed that teeth were removed successfully and that recovery was taking place except when cauterization was carried out. There was an initial wave of apoptosis that tapered off by 5 days. Next a spike in proliferation occurred in both torn epithelium and surrounding mesenchyme that lasted for at least 1 week. In long term followup we found that simple tooth removal delays but does not impact overall patterning. In contrast, cauterization of the dental lamina causes a block in tooth formation that does not recover from the cut edges (up to 8 months follow-up). The mesenchyme on its own is completely unable to induce new teeth from other types of epithelia such as oral mucosa or glandular epithelium. The dental epithelium is therefore instructive and is the key tissue that must be present for new teeth to form. Molecular readouts that will be presented include the location of putative stem cells (BrdU label retention, SOX2 antibody staining), changes in gene expression (in situs and RNAseq) and evidence of polarity of the epithelium being re-established (in situs). This data will be used to map out the sequence of recovery in dental epithelium leading to reestablishment of the Zahnreihen. Support or Funding Information Studies were supported by an NSERC Discovery Grant (RGPIN-2016-05477) to JMR. TMG was supported by an NIH F32 Postdoctoral Fellowship (F32DE024948). KB is supported by Killam and Michael Smith Foundation for Health Research postdoctoral fellowships. Palatal view of an adult gecko with approximately 40 functional teeth in each quadrant. Each marginal tooth defines the start of a Zahnreihen (diagonal row of unerupted teeth). Not shown is the continuous dental lamina to which all teeth are attached. This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
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 | 0,001 | 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 | 0,001 | 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 ».