[Genetic characterization of the N protein of subgroups A and B human respiratory syncytial viruses].

Objective: To clarify the genetic characteristics of N protein coding region of HRSV isolates from Beijing and GenBank downloaded sequences.

Methods: Reverse transciption polymerase chain reaction (RT-PCR) was performed to amplify the N protein gene of 2 A and 2 B subgroups HRSV isolates from Beijing in the year 2004. The RT-PCR products were sequenced for N protein coding region. The sequences of N protein coding region of 4 Beijing isolates and those downloaded from GenBank were compared and analyzed.

Results: The differences in number of nucleotide and deduced amino acid between 2 A Beijing 2004 isolates and prototype strain Long were 36-40 (3.1%-3.4%) and 4 (1.0%). The differences in number of nucleotide and deduced amino acid between 2 B Beijing 2004 isolates and prototype strain CH18537 were 17 (1.4%) and 1 (0.3%). The differences in number of nucleotide and deduced amino acid were 3-172 (0.25%-14.63%) and 0-18 (0-4.6%) respectively between 4 Beijing 2004 isolates and GenBank sequences.

Conclusion: N gene is the highly conservative gene in the HRSV genome. The variation between A and B subgroups were widely distributed in the entire gene of N protein, while the variation within the A or B subgroups HRSV was considerably lower.