Spatiotemporal Expression Mode of G9a in Development Process of Pharyngeal Tooth Morphology of Zebrafish

doi:10.13701/j.cnki.kqyxyj.2026.10.005

Abstract

Abstract: Objective: To explore the spatiotemporal expression pattern of G9a in zebrafish pharyngeal teeth during the key stage from occurrence to early morphogenesis. Methods: Using wild-type AB zebrafish as the model, embryos of 36-84 hpf (after fertilization within hours) were collected. The zebrafish pharyngoden-specific marker gene paired-like homeodomain 2 (pitx2), distal-less homeobox 2b (dlx2b), and the coding region fragment of the G9a gene were cloned by reverse transcriptase-polymerase chain reaction (RT-PCR) to prepare digoxin-labeled antisense RNA probes. The dynamic expression of G9a in the pharyngeal tooth development region was systematically detected by whole-embryo in situ hybridization whole-mount in situ hybridization (WISH) technology, and a co-localization comparison was made with the expression patterns of pitx2 and dlx2b. Results: The target gene fragment was successfully cloned by RT-PCR. The in situ hybridization showed that G9a was widely expressed in the pharyngeal region at 36-48 hpf. At 56-60 hpf, the pharyngeal tooth germ begins to specialization, and pitx2 and dlx2b show strong positive signals in specific areas. At this time, the expression area of G9a highly overlaps with that of pitx2 and dlx2b. During the morphogenetic stage of 72-84 hpf, G9a remains significantly expressed in the continuously developing pharyngodont primordium. Conclusion: This study, for the first time, revealed that G9a has a specific spatiotemporal expression pattern during the critical period of pharyngeal tooth development in zebrafish. Its expression region is highly consistent with the known pharyngeal tooth marker genes, suggesting that G9a may be involved in the morphogenesis process of zebrafish pharyngeal teeth through epigenetic regulatory mechanisms.

Key words: zebrafish, pharyngeal development, G9a, epigenetic regulation, whole embryonic in situ hybridization

ZU Shuai, WU Yunhai, PENG Jia, YANG Fei, LIU Yang, HU Hongmei, LI Wei. Spatiotemporal Expression Mode of G9a in Development Process of Pharyngeal Tooth Morphology of Zebrafish[J]. Journal of Oral Science Research, 2026, 42(10): 853-859.

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