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 polymerage 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 difierences 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 hishly 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 wag considerably lower. Key words: Respiratory Syncytial Viruses; Genes; Sequence analysis