OBJECTIVETo investigate a 272 base pair section of the 5'-non-coding region of genomic DNA from the peripheral blood monounuclear cells of healthy hepatitis virus C (HCV)-negative human subjects (not patients).

METHODSThis sequence section bears interest because (1) it harbors several potential methylation (Cp-rich) sites, and (2) it represents the largest part of its internal ribosomal entry site. A pre-PCR digestion protocol was established making consistent use of four restriction endonucleases selected for certain features: SmaI, XmaCI, MspI, and HpaII are inhibited if methylation(s) are present at certain cytosines within their cutting sequences.

RESULTSThe suspected HCV-specific sequence was found in the DNA of each subject tested. The pre-PCR digestion assay reveals individual differences in their pattern of methylation, which may be due to possible epigenetic phenomena.

CONCLUSIONSThe results provide formal proof that these HCV-specific sequences are contained in the genomic or extra chromosomal target DNA, and probably belong to a new class of endogenous sequences.

DNA Methylation ; Hepacivirus ; genetics ; Humans ; Restriction Mapping ; Sequence Homology, Nucleic Acid

To seek the optimum experiment methods of animal immunization with HCV gene and to explore the effect on antibody responses in mice immunized by pCD-HCV1 recombinant in different administration, recombinant pCD-HCV1 was constructed by technique of molecular biology and was injected into muscles of Balb/c of mice with different times, routes and dosage of inoculations as well as different treatment. The results showed that the serum antibody level reached 0.183±0.06,0.428±0.05,0.707±0.08 and 0.773±0.07(OD410 value) respectively after recombinant pCD-HCV1(100μg/mouse) were injected into mice once, twice, three times and four times. The antibody level of mice (n＝12) with four times inoculation was the highest; pCD-HCV1 was perfused into stomach orally in mice or were into mice by i.p, s.c and i.m(100μg/mouse, three times) in different routes (n＝6), and the antibody levels were 0.138±0.05, 0.178±0.07, 0.233±0.08 and 0.691±0.05 respectively; after the mice (n＝8) were inoculated with the pCD-HCV1 of different dosage(10μg, 50μg and 100μg) the antibody levels of three groups were 0.11±0.09, 0.33±0.04, and 0.700±0.07, and the results showed a significant difference (P＜0.01); Mice was injected with procaine (100μl, 0.4mg) by i.m or s.c. Then pCD-HCV1 was injected into mice and antibody levels were higher than that of mice immunized directly with recombinant pCD-HCV1 of same dosage. The results may provide a reference data deserved for screening the optimum immunization method of development HCV-DNA-based vaccine in mice model.

OBJECTIVETo study the severe acute respiratory syndrome (SARS)-associated coronavirus genotype and its characteristics.

METHODSA SARS-associated coronavirus isolate named ZJ01 was obtained from throat swab samples taken from a patient in Hangzhou, Zhejing province. The complete genome sequence of ZJ01 consisted of 29,715 bp (GenBank accession: AY297028, version: gi: 30910859). Seventeen SARS-associated coronavirus genome sequences in GenBank were compared to analyze the common sequence variations and the probability of co-occurrence of multiple polymorphisms or mutations. Phylogenetic analysis of those sequences was done.

RESULTSBy bioinformatics processing and analysis, the 5 loci nucleotides at ZJ01 genome were found being T, T, G, T and T, respectively. Compared with other SARS-associated coronavirus genomes in the GenBank database, an A/G mutation was detected besides the other 4 mutation loci (C:G:C:C/T:T:T:T) involved in this genetic signature. Therefore a new definition was put forward according to the 5 mutation loci. SARS-associated coronavirus strains would be grouped into two genotypes (C:G:A:C:C/T:T:G:T:T), and abbreviated as SARS coronavirus C genotype and T genotype. On the basis of this new definition, the ZJ01 isolate belongs to SARS-associated coronavirus T genotype, first discovered and reported in mainland China. Phylogenetic analysis of the spike protein gene fragments of these SARS-associated coronavirus strains showed that the GZ01 isolate was phylogenetically distinct from other isolates, and compared with groups F1 and F2 of the T genotype, the isolates of BJ01 and CUHK-W1 were more closely related to the GZ01 isolate. It was interesting to find that two (A/G and C/T) of the five mutation loci occurred in the spike protein gene, which caused changes of Asp to Gly and Thr to Ile in the protein, respectively.

CONCLUSIONAttention should be paid to whether these genotype and mutation patterns are related to the virus's biological activities,epidemic characteristics and host clinical symptoms.

Genotype ; Humans ; Middle Aged ; Mutation ; SARS Virus ; genetics