Two short interfering RNAs (siRNA-RdRp1286, siRNA-RdRp1441) and one short interfering RNA (siRNA-OCP117), targeted to the RNA dependent RNA polymerase (RdRp) gene and outer capsid protein (OCP) gene of Grass carp reovirus (GCRV) respectively, were chemically synthesized and transfected into the CIK cells by lipofectamine 2000. 6 hours after transfection, the transfected CIK cells were challenged with GCRV. The culture media were collected at 48h post challenge and the virus was titrated in microculture system to evaluate the inhibition effect on GCRV replication mediated by siRNAs. Referring to the mRNA level of housekeeping gene beta-actin, RT-PCR was applied to detect the level of GCRV mRNA in transfected and challenged CIK cells. The results showed that the viral titer (lgTCID50/0. 1mL) in siRNA-RdRp1286, siRNA-RdRp1441 and siRNA-OCP117 transfected CIK cells were 4.41 +/- 0.16, 3.83 +/- 0.44 and 1.94 +/- 0.42 respectively, which were significantly lower than that in virus infection positive control (7.92 +/- 0.52) (P < 0.01). No significant change in viral titer was observed in the group transfected with siRNA negative control after challenged with GCRV (7.50 +/- 0.17, P > 0.05). Compared with the mRNA transcriptional level of beta-actin gene in virus infection positive control, the mRNA levels of GCRV in siRNA-RdRpl 286, siRNA-RdRp1 441 and siRNA-OCP117 transfected CIK cells were reduced significantly and the inhibition rate reached to (82.08 +/- 2.15)%, (89.19 +/- 1.14).% and (92.62 +/- 0.17)%, respectively. The mRNA level of GCRV in the siRNA negative control group had no noticeable change (P > 0 05).
Animals ; Carps ; virology ; Cells, Cultured ; RNA, Small Interfering ; chemical synthesis ; chemistry ; pharmacology ; Reoviridae ; drug effects ; genetics ; Reverse Transcriptase Polymerase Chain Reaction ; Virus Replication ; drug effects

In order to study the proliferation inhibition effect of H5N1 subtype avian influenza virus (AIV) with small interfere RNA (siRNA), a total of 4 siRNAs were designed in accordance with the NP and PA genes of H5N1 subtype AIV, the siRNAs were then transfected to chicken embryo fibroblast(CEF), CEF was infected with H5N1 subtype AIV after 6 hrs. Virus titer of cell supernatant was tested at 16-56hrs post infection, and pathological changes of the cells was observed; mRNA levels of NP, PA, HA and p13-actin gene were tested at 36hrs post infection. The results showed that these 4 siRNAs could inhibit the prolif-eration of H5N1 subtype AIV in CEF in varying degrees, and one siRNA targeting PA was best per-formed. The experimental results also showed that the inhibition effect was decreased with the time prolonged. This research provides a basis for further studying RNAi on AIV prevention and control.
Actins ; genetics ; Animals ; Chick Embryo ; DNA Primers ; genetics ; Fibroblasts ; virology ; Hemagglutination ; Hemagglutinin Glycoproteins, Influenza Virus ; genetics ; Hemagglutinins ; genetics ; Humans ; Influenza A Virus, H5N1 Subtype ; genetics ; growth & development ; physiology ; RNA Interference ; RNA Replicase ; genetics ; RNA, Small Interfering ; chemical synthesis ; genetics ; RNA-Binding Proteins ; genetics ; Real-Time Polymerase Chain Reaction ; Specific Pathogen-Free Organisms ; Transfection ; Viral Core Proteins ; genetics ; Viral Proteins ; genetics ; Virus Replication

Autophagy-related protein 8 (Atg8) is an essential component of autophagy formation and encystment of cyst-forming parasites, and some protozoa, such as, Acanthamoeba, Entamoeba, and Dictyostelium, have been reported to possess a type of Atg8. In this study, an isoform of Atg8 was identified and characterized in Acanthamoeba castellanii (AcAtg8b). AcAtg8b protein was found to encode 132 amino acids and to be longer than AcAtg8 protein, which encoded 117 amino acids. Real-time PCR analysis showed high expression levels of AcAtg8b and AcAtg8 during encystation. Fluorescence microscopy demonstrated that AcAtg8b is involved in the formation of the autophagosomal membrane. Chemically synthesized siRNA against AcAtg8b reduced the encystation efficiency of Acanthamoeba, confirming that AcAtg8b, like AcAtg8, is an essential component of cyst formation in Acanthamoeba. Our findings suggest that Acanthamoeba has doubled the number of Atg8 gene copies to ensure the successful encystation for survival when 1 copy is lost. These 2 types of Atg8 identified in Acanthamoeba provide important information regarding autophagy formation, encystation mechanism, and survival of primitive, cyst-forming protozoan parasites.
Acanthamoeba castellanii/cytology/*genetics/physiology ; Amebiasis/*parasitology ; Amino Acid Sequence ; Autophagy ; Cell Membrane/metabolism ; DNA, Protozoan/chemistry/genetics ; Gene Dosage ; Gene Silencing ; Genes, Reporter ; Humans ; Molecular Sequence Data ; Phagosomes/metabolism ; Protein Isoforms ; Protozoan Proteins/*genetics/metabolism ; RNA, Messenger/genetics ; RNA, Protozoan/genetics ; RNA, Small Interfering/chemical synthesis/genetics ; Recombinant Fusion Proteins ; Sequence Alignment