Artikel
M and N gene sequence analyses on the newly occurred SARS CoV in Guangdong
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Veröffentlicht: | 26. Mai 2004 |
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Background: The first case of SARS was reported in Foshan of Guangdong Province on Nov 16, 2002 and caused a outbreak. One year later, a new case of SARS was reemerged in Guangzhou on Dec 16, 2003. The patient showed a positive IgM and IgG to SARS-CoV in serum, and viral sequences were amplified by Light Cycle PCR in throat specimen, but the isolation of virus from clinical specimen was unsuccessful. The M and N genes were thus sequenced to confirm the newly occurred SARS and look for possible origin.
Methodology: RNA was extracted from the samples and used for RT-PCR by specific M and N gene primers, and the PCR products were used for direct sequencing.
Results: In comparison with published Genbank sequences of SARS CoV, GD03T0013 has a difference of 1 base in M and 4 bases in N, the coded amino acid sequence is the same in M and has a difference of 3 amino acids in N, and two of the amino acids changed from hydrophilic threonine to hydrophobic isoleucine. Compared with the early and middle phase SARS-CoV of the 2002-2003 outbreak, the M gene of GD03T0013 has a nucleotide homology of 99.8% and 99.7%. Compared with GD01, SZ3, palm civetand GD69, the N genes of GD03T0013 has a nucleotide homology of 99.7%, 99.7%and 99.6%. amino acid homology of 99.1%, 99.1%and 98.8%.
Conclusion: The origin of SARS CoV of the new patient may come from the palm civet, The disease showed a less severe symptoms and signs, and caused no human to human transmission. So the virus may belong to a different branch compared with the SARS CoV of the last outbreak.