冠状病毒Coronavirusl论文-2000 Evidence of genetic diversity generated by recombination among avian coronavirus IBV.pdf

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1、ArchVirol(2000)145:2135–2148EvidenceofgeneticdiversitygeneratedbyrecombinationamongaviancoronavirusIBVC.-W.LeeandM.W.JackwoodDepartmentofAvianMedicine,CollegeofVeterinaryMedicine,TheUniversityofGeorgia,Athens,Georgia,U.S.A.AcceptedMarch24,2000Summary.Previously,wedemons

2、tratedthattheDE072strainofIBVisarecom-binantwhichhasanIBVstrainD1466-likesequenceintheSgene.Herein,weanalyzedtheremaining3.8kb30endofthegenome,whichincludesGene3,Gene4,Gene5,Gene6,andthe30non-codingregionoftheDE072andD1466strains.Thosetwoviruseshadhighnucleotidesimilari

3、tyinGene4.However,theotherindividualgeneshadamuchdifferentlevelofsequencesimilaritywiththesamegeneoftheotherIBVstrains.ThegenomeoffiveIBVstrains,ofwhichthecom-pletesequenceofthe30endofthegenomehasbeendetermined,weredividedatanintergenic(IG)consensussequence(CTGAACAAorCTT

4、AACAA)andcom-paredphylogenetically.PhylogenetictreesofdifferenttopologyindicatedthattheconsensusIGsequencesandthehighlyconservedsequencearoundthisregionsmayserveasrecombination`hotspots'.PhylogeneticanalysisofselectedregionsofthegenomeoftheDE072serotypefieldisolatesfurth

5、ersupportthoseresultsandindicatethatisolateswithinthesameserotypemayhavedifferentamountsofnucleotidesequencesimilaritywitheachotherinindividualgenesotherthantheSgene.PresumablythisoccursbecausetheconsensusIGsequenceservesasthetemplateswitchingsitefortheviralencodedpolym

6、erase.IntroductionInfectiousbronchitisviruscausesahighlycontagiousupper-respiratorydiseaseinchickens.Thediseaseischaracterizedbyincreasedocularandnasalsecre-tions,excessmucusinthetrachea,decreasedweightgainandfeedefficiencyinbroilers,anddeclinesineggproductionandeggquali

7、tyinlayers.Althoughliveattenuatedvaccinesareavailable,IBVcontinuestobeasevereeconomicproblemincommercialchickensbecausemanydifferentserotypesofthevirusexistanddonotcrossprotect[3].2136C.-W.LeeandM.W.JackwoodInfectiousbronchitisvirus(IBV)isacoronavirusintheneworderNidovi

8、rales[4].MembersoftheNidoviralesorderhaveasinglestrandedpositivesenseRNAgenomeandproducea30nestedsetofsubgenom