Wereportedanovelmammalianreovirus,designedBYD1,isolatedfromthroatswabsofpatientswithsevereacuterespiratorysyndrome(SARS),in2003.Inthepresentstudy,wefirstlycomparedthegenomeelectrophoreticmigrationpatternsofreovirusBYD1with3prototypereovirusstrainsbypolyacrylamidegelelectrophoresis(PAGE)anddeterminedthecompletenucleotidesequenceoftheS1genesegmentofBYD1bysingleprimeramplificationtechnique.TheelectropherogramofBYD1wasdifferentfromthoseofthe3prototypestrainsandanyotherreovirusisolatesreportedbefore.TheentireS1segmentsequenceofBYD1is1437bplongwithtwomeaningfulopenreadingframes(ORFs).ThelongestORFencodesσ1,thecellattachmentprotein,andthesecondlongestORFsupposedlyencodesσ1s,animportantnonstructuralvirulencefactor.TheterminalsequencesofS1segmentare5'GCUAand3'UCAUC,whichareconsistentwiththoseofothermammalianreoviruses.Thehighesthomologyofdeducedσ1aminoacidsequenceis64%identitywithknownmammalianreoviruses.PhylogeneticanalysisofbothS1nucleotidesequenceandσ1aminoacidsequenceindicatedtheBYD1isolatebelongedtoanewcladeofserotype2group.TheresultsofthisstudyshowedthattheBYD1S1segmentwasmarkedlydifferentfromthoseofisolatesreportedbeforeandBYD1wasanovelhumanreovirusisolate.
