The complete nucleotide sequence of classical swine fever virus (CSFV) strain cF114 (F114 strain propa- gated on PK-15 cells) was cloned by RT-PCR. The analyses of nucleotide and amino acids identity between cF114 and...The complete nucleotide sequence of classical swine fever virus (CSFV) strain cF114 (F114 strain propa- gated on PK-15 cells) was cloned by RT-PCR. The analyses of nucleotide and amino acids identity between cF114 and F114, Brescia, Alfort or C strain were 99.41%, 96.80%, 86.03%, 95.70% and 99.28%, 98.54%, 93.33%, 97.41% re- spectively. The cDNA fragments with correct sequence were ligated into a full-length cDNA and inserted into pMC18 plasmid (pMC12297). A full-length infectious viral RNA was synthesized by runoff transcription and transfected to PK15 cells. Viruses were recovered from transfected cells which wese titrated on PK-15 cells by endpoint dilution and indirect immunofluorescence with a CSFV-specific monoclonal antibody. The antigenicity and replication kinetics of the plasmid-derived virus (vM12297) were similar to the parental virus in vitro. The E01 or E2 gene was replaced with the genes from strain C and the pM/CE01 and pM/CE2 with chimeric full-length cDNA of cF114 were generated. The infectious viruses were obtained from pM/CE01 and pM/CE2. Both of the chimeric viruses can infect PK-15, SK- 6 and primary testicle cell of swine. The chimeric viruses can grow to a titer of 8?05 F-PFU/mL. These results are very important for understanding the genes related to the CSFV propagation and pathogenesis.展开更多
Nanog is a novel transcription factor specifically expressed in mouse embryonic stem cells (mES cells). It has been reported that Nanog plays an essential role in maintaining multi-potency of ES cells. The expression ...Nanog is a novel transcription factor specifically expressed in mouse embryonic stem cells (mES cells). It has been reported that Nanog plays an essential role in maintaining multi-potency of ES cells. The expression of Nanog is very sensitive to ES cells differentiation, making Nanog one of the best markers to indicate the status of ES cells. In this study, we developed an efficient method to construct Nanog promoter driven EGFP reporter system based on the BAC homologous recombination. We further generated a Nanog-EGFP reporter mES cell line. This reporter mES cell line exhibited features similar to those of normal mES cells, and the EGFP reporter efficiently reflected the expression of Nanog, indi- cating the differentiation status of mES cells. We achieved a reliable experimental reporter system to research self-renewal and differentiation of mES cells. The system could facilitate research on culture system of mES cells and researches on the expression and regulation of Nanog and other related fac- tors in mES cells.展开更多
基金This work was sup-ported by the Special Funds for the State Major Basic Research of China(Grant No.G 199901 1904)the National Natural Science Foundation of China(Grant No.301 70041)and the Ministry of Education of China.
文摘The complete nucleotide sequence of classical swine fever virus (CSFV) strain cF114 (F114 strain propa- gated on PK-15 cells) was cloned by RT-PCR. The analyses of nucleotide and amino acids identity between cF114 and F114, Brescia, Alfort or C strain were 99.41%, 96.80%, 86.03%, 95.70% and 99.28%, 98.54%, 93.33%, 97.41% re- spectively. The cDNA fragments with correct sequence were ligated into a full-length cDNA and inserted into pMC18 plasmid (pMC12297). A full-length infectious viral RNA was synthesized by runoff transcription and transfected to PK15 cells. Viruses were recovered from transfected cells which wese titrated on PK-15 cells by endpoint dilution and indirect immunofluorescence with a CSFV-specific monoclonal antibody. The antigenicity and replication kinetics of the plasmid-derived virus (vM12297) were similar to the parental virus in vitro. The E01 or E2 gene was replaced with the genes from strain C and the pM/CE01 and pM/CE2 with chimeric full-length cDNA of cF114 were generated. The infectious viruses were obtained from pM/CE01 and pM/CE2. Both of the chimeric viruses can infect PK-15, SK- 6 and primary testicle cell of swine. The chimeric viruses can grow to a titer of 8?05 F-PFU/mL. These results are very important for understanding the genes related to the CSFV propagation and pathogenesis.
基金Supported by the National Natural Science Foundation of China (Grant No. 30421004)
文摘Nanog is a novel transcription factor specifically expressed in mouse embryonic stem cells (mES cells). It has been reported that Nanog plays an essential role in maintaining multi-potency of ES cells. The expression of Nanog is very sensitive to ES cells differentiation, making Nanog one of the best markers to indicate the status of ES cells. In this study, we developed an efficient method to construct Nanog promoter driven EGFP reporter system based on the BAC homologous recombination. We further generated a Nanog-EGFP reporter mES cell line. This reporter mES cell line exhibited features similar to those of normal mES cells, and the EGFP reporter efficiently reflected the expression of Nanog, indi- cating the differentiation status of mES cells. We achieved a reliable experimental reporter system to research self-renewal and differentiation of mES cells. The system could facilitate research on culture system of mES cells and researches on the expression and regulation of Nanog and other related fac- tors in mES cells.
