Jin Yongfeng

Drosha protein levels are translationally regulated during Xenopus oocyte maturation

Drosha is required for the nuclear processing of pri- to pre-miRNAs. Drosha itself is translationally regulated during oocyte-to-egg maturation. Upon completion of meiosis, Drosha mRNA is translationally activated. This leads to a subsequent increase of endogenous miRNAs.

Inhibition of BmNPV replication in Bombyx mori cell by dsRNA triggered RNA interference

RNA interference (RNAi) causes degradation of targeted endogenous RNA in many diverse organisms. To investigate the effect of dsRNA on silkworm cells, we transfected three kinds of synthetic dsRNAs of 435 bp(Ap1), 300 bp(Ap2) and 399 bp(AH) in length against the various regions of BmNPV’s DNA polymerase gene and DNA helicase gene, which are indispensable for viral replication in silkworm cells by TransMessengerTM transfection Reagent. Results indicated that in the experiment where silkworm cells were infected with wild-strain BmNPV of the three dsRNAs, Ap2 and AH can effectively suppress the replication of virus, but Ap1 had no effect on the inhibition of viral replication. Ap2 and AH can reduce the infective titer of BmNPV with a peak change of approximately 3–4 logs on day 4 post-infection. The results of reverse transcript polymerase chain reaction (RT-PCR) and DNA dot blotting also indicated that the expression level of the two target genes and the quantity of viral DNA both distinctly decreased under the influence of Ap2 or AH. Furthermore, using fluorescence microscopy we analyzed the distribution patterns of dsRNA. Our studies revealed that a majority of dsRNA was localized in the nuclear periphery discontinuously after 24 h of transfection.

Identification and Analysis of Evolution of A-to-I RNA Editing Sites in Kv2 Gene in Arthropoda

A-to-I RNA editing alters protein codon to generate diversity, but its molecular mechanism and evolutionary characteristics are still not well-known. We analyzed RNA editing sites of Kv2 gene from species of five classes of Arthropoda. Seventeen A-to-I RNA editing sites were identified, including conservative and species-specific sites. Editing site 15(I/V) derived from 450 million years ago, is the most conservative RNA editing event yet reported in invertebrates. Also, some A-to-I RNA editing sites undergone convergent evolution. Based on these findings, co-transfection experiments were carried out, and the results indicate that RNA editing of Drosophila melanogaster Kv2 gene is mediated by the interaction between ADAR and exon-directed RNA secondary structure. This suggests that some exons play an important role in gene expression regulation, except protein-coding function.