Abstract:

Objective To explore the spatio-temporal mRNA expression pattern of death domain-associated protein (Daxx) in the whole process of zebrafish embryonic development, and to study the physiological role and possible molecule mechanism of Daxx in the process. Methods Whole-mount mRNA in situ hybridization (WISH) was performed to ascertain the spatio-temporal expression pattern of Daxx in the process of zebrafish embryonic development. Daxx expression was knocked down by using morpholino mediated gene knockdown. TUNEL and pH3 staining assay were applied to check cell apoptosis and proliferation in Daxx deficient embryos. The molecule mechanism of Daxx was explored by using Real-Time PCR. Results Knock-down Daxx activated p53 dependent cell apoptosis pathway，thus caused increasing rate of apopotosis and malformation, whereas those could be rescued by p53 co-knockdown. Moreover, the acid-enriched domain of Daxx mediated the interaction between Daxx and p53 and regulated the expression of p53 target genes bax, mdm2, p21, and cyclin G1. Conclusion Daxx could bind to p53 via its specific motif and regulate the expression of key genes downstream of p53, which may be the key mechanism of Daxx during zebrafish embryonic development.

Key words: death domain-associated protein, p53, gene knockdown, zebrafish, cell apoptosis, embryonic development