Abstract:

Objective To study the temporal expressions of miR-9,miR-219 and Dicer gene during zebrafish embryonic development. Methods A total of 40 zebrafish embryos were selected at the 4th, 8th, 12th, 16th, 20th, 24th, 36th, 48th and 72th hour post fertilization (hpf), respectively. The total RNA was extracted with Trizol method and was reversely transcripted to cDNA with stem-loop primers. The gene expression levels of miR-9, miR-219 and Dicer were measured by Real-time PCR. Results The temporal mRNA expressions of miR-9, miR-219 and Dicer varied significantly during embryonic development with a pattern of peak curve (P<0.05). Compared with the total average level of gene expression, miR-9 was at a low level before 8 hpf (P<0.05), the expression increased continuously after 36 hpf. The expression levels at 48 hpf and 72 hpf were significantly higher than the total average level (P<0.01). The expression of miR-219 was at a low level before 8 hpf (P<0.05), increased rapidly at 20 hpf, reached the peak at 24 hpf, and maintained until 48 hpf (P<0.01). The Dicer gene in the early stage of embryonic development (4 hpf) expressed obviously (P<0.05), then the expression level decreased rapidly, reaching the lowest level at 16 hpf (P<0.05), and then pick up gradually until the last stage of embryonic development. Conclusion There is a certain regularity about the temporal expressions of miR-9, miR-219 and Dicer gene in zebrafish embryonic development. miR-9 mainly expresses in the late stage of embryonic development, miR-219 mainly expresses in the mid-embryonic stage, and Dicer gene mainly expresses in the early embryo and secondly in late embryonic stage. The result indicate that miR-9，miR-219 and Dicer play regulating roles during embryonic development.

Key words: Embryo, Development, MicroRNA, Dicer, Real-time PCR, Zebrafish