[Clinical detection of polymerase gene of SARS-associated coronavirus]

To analyze the heterogeneity of polymerase gene fragment of SARS-associated coronavirus from SARS patients, and establish a RT-PCR method for detecting SARS-associated coronavirus.

RT-PCR was performed using SARS coronavirus-specific primers to amplify the polymerase gene fragment of SARS-associated coronavirus from specimens of suspected and established SARS cases. The amplicons were cloned and sequenced. All the obtained sequences were compared with the sequence of published SARS-associated coronavirus, and alignment was proceeded with other coronavirus sequences.

Specific amplicons can be amplified from the sputum samples, throat swab and plasma of most SARS patients, and 8 were random selected and sequenced. All of them possessed 100% homology with the published SARS-associated coronavirus sequence, while all the negative controls were RT-PCR negative. Nucleotide-sequence and amino acid-sequence alignment of the fragment BNI109 with other six known coronavirus show that the fragment BNI109 is more close to bovine coronavirus(BCV) and murine hepatitis virus(MHV). The BNI109 fragment showed 75% homology with BCV and MHV at amino acid level.

The polymerase fragment BNI109 of SARS coronavirus is highly conservative and is suitable for detecting SARS-associated coronavirus using RT-PCR method.