| Sulfolobus is a model for archaea genetic mechanism research,and its viruses have obtained more attention.As Sulfolobus is a powerful tool for research of archaea,study on the characteristic of their viruses will help to understand the genomic structure,origin and evolution of viruses.A novel Sulfolobus virus named STSV2 was isolated from Tengchong hot springs.STSV2 was a typical spindle virus with a spindle head(220×80nm),a long flexible tail with 20-100nm at one end.The optimum growth temperature was 75℃,The optimum growth pH was 3.1.The genome DNA of STSV2 was 75084 bp with C+G content of 35.07%.STSV2 has 80 ORFs and has a homology of 75%with STS V1.Only 50%of the ORFs have homologe with the other sequences in the databases.These ORFs related to DNA replication,modification,biosynthesis and metabolism of nucleotides,transcription and package of viruses.Among them,20%ORFs appeared to be archaeal-specific,and only 15%and 7%ORFs shared similarity with bacteria and eukarya,respectively.Few non-coding repeats were found in virus genomes,but at sites of 27902-27971 of STSV2 DNA,a few non-coding repeats with high A&T content were found.This sequence maybe related to origin of replication.164 of predictive promoters were detected.the up steam of-10 and-35 regions were found with A&T and TATA-box,respectively.Analysis of the frequent codon usage showed that STSV2 and its host bacteria have different codon usage bias.The phylogenetic evolution and motif of ORF 14,21,60,etc.were analyzed,and the S-adenosylmethionine-dependent methyltransferases(SAM or AdoMet-MTase),21S-adenosylmethionine-dependent methyltransferases(SAM or AdoMet-MTase)and 60-dUTPase were cloned and expressed.Study on genomic characteristics and its fuctional proteins activity of STSV2 will help us to understand the life of virus in the extreme environments... |
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