Early Post-fertilization Events in the Rat Model: New Insights on Sperm Decondensation Classification and Chromatin Remodeling Patterning.
Notice bibliographique
Résumé
Following fertilization, entry of the spermatozoon triggers the mature oocyte arrested at metaphase II to complete its second meiotic division; oocyte proteins are activated to induce sperm decondensation. Sperm decondensation is divided into four distinct stages: condensed, type a (partially decondensed), type b (totally decondensed) and type c (recondensing) nuclei. Once the spermatozoon has started decondensing, chromatin remodeling is initiated, during which protein exchange occurs and sperm specific proteins are replaced with maternal histones. When this exchange is complete, the paternal chromatin recondenses to form the male pronucleus. Our objective for this in vivo study was to describe sperm decondensation and chromatin remodeling in Sprague-Dawley rats, using both histone H4 acetylated at lysine 12 (H4ack12) and histone H3 phosphorylated at serine 10 (H3S10ph) as markers. H4ack12 is one of the first maternal histones to be incorporated onto the decondensing paternal chromatin and is responsible for decondensing the chromatin structure. In contrast, H3S10ph is involved in sperm chromatin compaction during chromatin remodeling. Males (n = 6-11) were mated overnight to two naturally cycling females; early embryos were collected at 9am the following morning and prepared for analysis by immunofluorescence and confocal microscopy. Interestingly, in the rat model, sperm decondensation occurred first at the base, then the tip and finally in the center of the sperm head. Therefore, in addition to the sperm decondensation stages enumerated above, we further subdivided type a nuclei into three sub classifications; type a1 (sperm base decondensed), type a2 (sperm base and tip decondensed) and type a3 nuclei (sperm base, tip and partial decondensation of the center region). Condensed sperm nuclei showed little to no immunoreactivity for either histone marker, possibly due to the tight packaging of the spermatozoon chromatin. Both histones H4ack12 and H3S10ph stained type a1 nuclei at the base, type a2 nuclei were stained at the base and tip, and type a3 nuclei at the base and tip and to a smaller extent in the central region of the sperm head. In contrast, two distinct patterns of chromatin remodeling were observed for type b and c nuclei; histone H4ack12 showed a homogenous staining, whereas histone H3S10ph displayed a ring-like staining around the sperm head. At pronuclear stages, the staining intensity remained high and homogenous with histone H4ack12 in contrast to a diminished staining intensity and a lost of the ring-like pattern with histone H3S10ph. The early and homogenous staining observed with histone H4ack12 suggests that in the early post-fertilization embryos, the paternal chromatin is decondensed, allowing protein exchange between the female and the male genome through all sperm decondensation stages. In contrast, the transient ring-like staining observed with histone H3S10ph suggests that chromatin condensation around the sperm head may be necessary for the formation of pronuclei. We propose that there are two distinct patterns of chromatin remodeling, one for H4ack12, a marker for opened chromatin structure, and a second for H3S10ph, a marker for condensed chromatin structure. Supported by CIHR.
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) | 0,001 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,001 | 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 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,002 | 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 ».