Ku70 Functions as an RNA Helicase to Regulate miR-124 Maturation and Neuronal Cell Differentiation / 生物化学与生物物理进展

ObjectiveHuman Ku70 protein mainly involves the non-homologous end joining (NHEJ) repair of double-stranded DNA breaks (DSB) through its DNA-binding properties, and it is recently reported having an RNA-binding ability. This paper is to explore whether Ku70 has RNA helicase activity and affects miRNA maturation. MethodsRNAs bound to Ku protein were analyzed by RNA immunoprecipitation sequencing (RIP-seq) and bioinfomatic anaylsis. The expression relationship between Ku protein and miRNAs was verified by Western blot (WB) and quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) assays. Binding ability of Ku protein to the RNAs was tested by biolayer interferometry (BLI) assay. RNA helicase activity of Ku protein was identified with EMSA assay. The effect of Ku70 regulated miR-124 on neuronal differentiation was performed by morphology analysis, WB and immunofluorescence assays with or without Zika virus (ZIKV) infection. ResultsWe revealed that the Ku70 protein had RNA helicase activity and affected miRNA maturation. Deficiency of Ku70 led to the up-regulation of a large number of mature miRNAs, especially neuronal specific miRNAs like miR-124. The knockdown of Ku70 promoted neuronal differentiation in human neural progenitor cells (hNPCs) and SH-SY5Y cells by boosting miR-124 maturation. Importantly, ZIKV infection reduced the expression of Ku70 whereas increased expression of miR-124 in hNPCs, and led to morphologically neuronal differentiation. ConclusionOur study revealed a novel function of Ku70 as an RNA helicase and regulating miRNA maturation. The reduced expression of Ku70 with ZIKV infection increased the expression of miR-124 and led to the premature differentiation of embryonic neural progenitor cells, which might be one of the causes of microcephaly.

Laboratory confirmation of the first influenza A (H1N1) imported case in Mainland China / 病毒学报

The clinical throat swab specimen of an imported suspected case of influenza A (H1N1) was detec ted with real-time PCR, RT-PCR and subsequently confirmed by gene sequencing. The presence of influ enza A (H1N1) virus confirmed the first case with A (H1N1) infection in Mainland China.

Preparation and identification of dengue virus with deletion mutation of capsid protein / 南方医科大学学报

<p><b>OBJECTIVE</b>To generate rescued viruses with deletion mutation of capsid protein from dengue virus type 2 isolated in China (DEN2-43).</p><p><b>METHODS</b>On the basis of infectious full-length cDNA clone pD212 of DEN2-43 strain virus, the deletion mutants were constructed by fusion PCR, from which the rescued viruses with deletion mutation of capsid protein were generated by transcription in vitro and electroporation.</p><p><b>RESULT AND CONCLUSION</b>Sequence analysis demonstrated that the deletion mutations had been successfully inserted into the rescued viruses obtained. These mutant viruses may hold the key for elucidating the effects of deletion mutation of capsid protein on the biological characteristics of dengue virus.</p>