B Ma1, C Hang, A Papa. 1. Institute of Virology, Chinese Academy of Preventive Medicine, Beijing 100052, China.
Abstract
OBJECTIVE: To determine the complete sequences of glycoprotein (M) gene of Crimean-Congo hemorrhagic fever virus (CCHFV) Chinese isolates (Xinjiang hemorrhagic fever virus, XHFV) BA66019, BA8402 BA88166 and to compare and analyze the relationships among the viruses. METHODS: Based on the conserved reverse complementarity of the CCHFV genomic termini, a primer PCM-Tag was designed and used together with random hexmers to initiate reverse transcription of viral RNA to synthesize cDNA. The latter was amplified with single primer PCM-Tag using the proof-reading DNA polymerase to produce the complete M gene. The PCR products were gel-purified and the whole M segment was sequenced and the comparison and analysis were performed aided by computer for the phylogenesis and coding strategy. RESULTS: Comparison of the whole M gene sequences of XHFV reference strain BA66019 with international prototype CCHFV IbAr10200 showed an excess of 5 base pairs in length, resulting in 5,365 bp; while BA8402 and BA8816 are 5,365 bp long, 4 more base pairs than IbAr10200. The first start codons of long ORFs were located at the 78th base pair in M gene of BA66019, BA8402 and BA88166, which were 15 base pairs prior to that of IbAr10200. The precursors encoded by these M genes were totaled 1,689 amino acids (AA), 6 AAs more than that of IbAr10200. The similaries between CCHFV M genes in nucleotide level were: 80.9% (IbAr10200-BA66019), 80.2% (IbAr10200-BA8402), 80.2% (IbAr10200-BA88166), 83.7% (BA8402-BA66019), 83.6% (BA88166-BA66019), and 99.0% (BA8402-BA88166), respectively. The corresponding similarities in amino acid level were 85.1%, 86.3%, 86.6%, 87.8%, 88.0%, and 98.8%, respectively. The similarities of M genes of CCHFVs and Dugbe virus in both nucleotide and amino acid levels were around 55% and 37%, which were much lower than those among CCHFVs. CONCLUSION: The M genes of XHFVs and IbAr10200 formed respective independent phylogenetic branches genetically and the human-origin isolate BA88166 might be a variant of tick-borne BA8402, suggesting that there was only one kind virus prevailing in Xinjiang epidemic areas in 1980s.
OBJECTIVE: To determine the complete sequences of glycoprotein (M) gene of Crimean-Congo hemorrhagic fever virus (CCHFV) Chinese isolates (Xinjiang hemorrhagic fever virus, XHFV) BA66019, BA8402BA88166 and to compare and analyze the relationships among the viruses. METHODS: Based on the conserved reverse complementarity of the CCHFV genomic termini, a primer PCM-Tag was designed and used together with random hexmers to initiate reverse transcription of viral RNA to synthesize cDNA. The latter was amplified with single primer PCM-Tag using the proof-reading DNA polymerase to produce the complete M gene. The PCR products were gel-purified and the whole M segment was sequenced and the comparison and analysis were performed aided by computer for the phylogenesis and coding strategy. RESULTS: Comparison of the whole M gene sequences of XHFV reference strain BA66019 with international prototype CCHFVIbAr10200 showed an excess of 5 base pairs in length, resulting in 5,365 bp; while BA8402 and BA8816 are 5,365 bp long, 4 more base pairs than IbAr10200. The first start codons of long ORFs were located at the 78th base pair in M gene of BA66019, BA8402 and BA88166, which were 15 base pairs prior to that of IbAr10200. The precursors encoded by these M genes were totaled 1,689 amino acids (AA), 6 AAs more than that of IbAr10200. The similaries between CCHFV M genes in nucleotide level were: 80.9% (IbAr10200-BA66019), 80.2% (IbAr10200-BA8402), 80.2% (IbAr10200-BA88166), 83.7% (BA8402-BA66019), 83.6% (BA88166-BA66019), and 99.0% (BA8402-BA88166), respectively. The corresponding similarities in amino acid level were 85.1%, 86.3%, 86.6%, 87.8%, 88.0%, and 98.8%, respectively. The similarities of M genes of CCHFVs and Dugbe virus in both nucleotide and amino acid levels were around 55% and 37%, which were much lower than those among CCHFVs. CONCLUSION: The M genes of XHFVs and IbAr10200 formed respective independent phylogenetic branches genetically and the human-origin isolate BA88166 might be a variant of tick-borne BA8402, suggesting that there was only one kind virus prevailing in Xinjiang epidemic areas in 1980s.