Abstract: Objective To explore the role of microRNAs(miRNAs) during early neurodevelopment in mammals with Dicer1 conditional knockout(cKO)mouse by RNA-seq. Methods The animals were divided into Ctrl group and cKO group. HE and immunofluorescence staining were used to observe the histological morphology; Extract total RNA of E14.5 D6-Cre-Dicer1 mice dorsal cortex, using RNA-seq technique to analyze differences at transcriptional level. Results Animals in cKO groups died within a month or so, abnormal development of cortical and hippocampal was recorded at P3. In cKO group transcription expression was different significantly,45 differentially expressed genes were screened, including 11 up-regulated and 34 down-regulated genes(P＜0.05)mainly enriched in Wnt signaling pathway, DNA damage response signaling pathway and others. Conclusions At E14.5 cortex, Dicer1 is involved in the regulation of multiple signaling pathways, affecting partial cortical laminar genes expres- sion, inhibiting the expression of lncRNA Xist and regulating cortical development.

Key words: Dicer1, D6-Cre, dorsal cortex, RNA-seq, lncRNA Xist