The 40-91 aa sequence of porcine epidemic diarrhea virus ORF3 protein is the key structural domain controlling its location in cytoplasm / 生物工程学报

ORF3 protein, the single accessory protein encoded by porcine epidemic diarrhea virus (PEDV), is related to viral pathogenicity. In order to determine the cytoplasmic location signal of PEDV ORF3, we constructed a series of recombinant plasmids carrying full-length or truncated segments of PEDV DR13 ORF3 protein. When the acquired plasmids were transfected into Vero cells, expression and distribution of the EGFP-fused full-length ORF3 protein and its truncated forms in the cells were observed by laser confocal microscopy. The results showed that ORF3 protein or their truncated forms containing 40-91 aa segment including two transmembrane domains were localized in the cytoplasm, whereas ORF3 truncated peptides without the 40-91 aa segment were distributed in the whole cell (in both cytoplasm and nucleus). This suggests that the 40-91 aa is the key structural domain determining cytoplasmic location of PEDV ORF3 protein. The discovery provides reference for further clarifying intracellular transport and biological function of PEDV ORF3 protein.

Cloning,Expression and Sub-cellular Localization of APOBEC-3F and -3G and Their Effect on HBV / 生物化学与生物物理进展

APOBEC(apolipoprotein B mRNA-editing enzyme catalytic-polypeptide) family members were reported as innate immune molecules with anti-viral activity for many viruses, such as HIV and HBV.In order to understand the function of APOBEC, the APOBEC-3F and-3G were cloned, expressed, and the sub-cellular localization of them was detected.The genes of APBEC-3F and-3G were cloned from PHA-stimulated PMBC and expressed in the MDCK cell by transfection.The sub-cellular localization of APOBEC-3F and-3G were detected by immunofluorescence.APOBEC-3F and-3G were cloned by RT-PCR and confirmed by DNA sequencing.The immunofluorescence indicated APOBEC-3F and-3G were located in the cytosal.APOBEC-3F and-3G could inhibit HBV replication effectively in HepG2.2.15 cell.APOBEC-3F and-3G could not be trans-located into nuclear by nuclear location signal(NLS) or bi-NLS(B-NLS).These results will help the future research on the function of APOBEC.