Adeno-associated virus mediated p53 gene silence in marmosets / 中国比较医学杂志

Objective To decrease the p53 gene expression at cellular and animal levels in marmoset using RNA interference technique.Methods The shRNA interference sequences were designed and inserted into the adeno-associated virus vector plasmid after bioinformatics analysis.The plasmids were transfected into African green monkey kidney cos-7 cells.The suppression of p53 mRNA was detected by real-time PCR, and the changes of p53 protein expression were detected by Western bolt.The adeno-associated virus-8 was injected through the hind leg vein.The changes of p53 protein expression in the liver tissue was detected by Western blot and immunohistochemistry.Results We screened two RNA interference effective arget sequences.The expression of p53 mRNA was suppressed ( 82.7 ±8.1 )% and ( 80.7 ± 7.5)%, respectively (P<0.05), and the expression of p53 protein was decreased (77.3 ±11.5)% and (73.7 ± 10.7)%, respectively (P<0.05).The two marmosets after virus infection showed that there were virus distributions in the liver, testes, and neck detected by in vivo fluorescence imaging.The expression of p53 in the marmoset liver was detected by western blot, immunohistochemistry analysis showing no obvious changes.Conclusions In the present study, the decrease of P53 gene expression at cellular level is achieved, however, the liver P53 protein in the marmoset liver is not significantly changes.Further optimization of the way of infection is needed in the future.

Validation of the silencing site of rhesus monkey P21 gene in COS-7 cells / 中国实验动物学报

Objective To screen the effective silencing targets of P21 gene at the cellular level in rhesus monkey . Methods To detect the expression of P21 gene in COS-7 cells ( derived from the kidney of African green monkey , Cerco-pithecus aethiops).Four small hairpin RNA (shRNA) sequences targeting rhesus monkey P21 gene were designed and in-serted into lentivirus-based gene silencing constructs FUGW-TDT.The vectors were transfected into COS-7 cells respective-ly.The suppression of P21 mRNA was detected by real-time PCR, and the expression of P21 protein was detected by West-ern blot assay .Results Four gene-silencing sequences were screened that lied in 541-561 bp, 542-562 bp, 215-239 bp, and 624-648 bp of the rhesus monkey P21 mRNA.Their silencing rate was (91.82 ±3.21)%, (82.47 ±2.48)%, (81.31 ±2.69 )% and ( 87.35 ±4.59 )%, and the protein expression was ( 11.97 ±0.70 )%, ( 20.22 ±0.65 )%, ( 23.21 ± 0.63)%and (14.42 ±0.86)%, respectively.Conclusions Four effective silencing target sequences are screened at cel-lular level , which can be used in gene silencing research of rhesus monkeys .

Establishment of an indirect immunofluorescence assay for detection of murine norovirus / 中国比较医学杂志

Objective To establish an indirect immunofluorescence assay for detection of murine norovirus ( MNV) .Methods Mouse leukaemic monocyte macrophage cell line RAW 264.7 cells were infected with MNV-1 and cultured for 36 hours to collect the virus and uninfected cells , and to make antigen glass slides .BALB/c mice were gavaged with MNV-1 (107 TCID50) and infected sera were collected as positive control .The serum was 1:10 diluted and used for measuring MNV antibody by immunofluorescence assay ( IFA ) .80 serum samples were tested using the two methods , IFA and ELISA, and the discrepant samples were validated by Western blotting .Results RAW264.7 cells were infected with MNV-1 for 36-48 h, showing an infection rate of 60% of the cells, and the cells infected for 36 h were preferred.IFA method was used to detect the serum with MNV-1 infection and showed that the antibody content was gradually increased at one week after infection , reaching a maximum antibody concentration at 4 weeks after infection , and maintained a stable level later .The mouse serum at four weeks after MNV-1infection was used as positive quality control . Among the 80 serum samples , 27 positive and 53 negative cases were detected by IFA method , and 32 positive and 48 negative cases were detected by ELISA .The five discrepant samples were verified by Western blotting , resulted in 3 positive and 2 negative cases . The coincidence rate of IFA was 96.0% and that of ELISA methods was 97.5%. Conclusions Basically, immunofluorescence assay can be used to detect the MNV-1 infection in mice, although false negative result may occur occasionally .IFA and ELISA detection can be selected as initial screening measures , and use Western blot assay to verify the discrepant samples .

Rhesus monkey P53 gene silencing at the cellular level / 中国比较医学杂志

Objective In order to establish a rhesus monkey model of p53 gene silencing, firstly we screened and determined the effective silencing targets of p53 gene at the cellular level in rhesus monkey.Methods The expression of p53 gene was detected in COS-7 cells ( derived from the kidney of the African Green Monkey, Cercopithecus aethiops).Three small hairpin RNA ( shRNA) sequences targeting rhesus monkey p53 gene were designed, analysed by bioinformatics, and inserted into lentivirus-based gene silencing constructs FUGW-TDT.The plasmids of p53-RNAi and control vector were transfected into the COS-7 cells, respectively.The suppression of p53 mRNA was detected by real-time PCR, and the changes of p53 protein expression were detected by Western blot assay.Results p53 gene expression was detected in COS-7 cells.Bioinformatics analysis showed that three gene-silencing sequences were screened which lied in the open reading frame ( ORF) region and targeted 238 -258bp, 681 -701bp, 169 -189bp of the rhesus monkey p53 mRNA.At 48 hrs after transfection of the three silencing constructs, p53 mRNA was suppressed by(87.17 ±4.03)%, ( 72.62 ±4.11)% and(76.22 ±0.98 )%, and p53 protein was suppressed by ( 84.44 ±2.18 )%, ( 71.04 ±1.18)% and ( 74.17 ±0.95 )%, respectively. Conclusions We obtained three effective target sequences showing high efficiency in p53silencing, which can be used in further studies on gene silencing in rhesus monkey.