冠狀病毒Coronavirusl論文-2012 [Advances in Experimental Medicine and Biology] The Effects of Noise on Aquatic Life Volume 730 __ A New Model for.pdf

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1、26ANEWMODELFORCORONAVIRUSTRANSCRIPTIONS.G.SawickiandD.L.SawickiDepartmentofMicrobiologyandImmunologyMedicalCollegeofOhioTole!io,Ohio43699I.ABSTRACTCoronavirusescontainanunusuallylong(27-32,000ribonucleotide)positivesenseRNAgenomethatispolyadenylatedatthe3'endandcappedatthe5'e

2、nd.Inadditiontothegenome,infectedcellscontainsubgenomicmRNAsthatforma3'co-terminalnestedsetwiththegenome.Inadditiontotheircommon3'ends,thegenomeandthesubgenomicmRNAscontainanidentical5'leadersequence.Thetranscriptionmechanismthatcoro?navirusesusetoproducesubgenomicmRNAisnotkn

3、ownandhasbeenthesubjectofspeculationsincesequencingofthesubgenomicmRNAsshowedtheymustarisebydis?continuoustranscription.Thecurrentmodelcalledleader-primedtranscriptionhassub?genomicmRNAstranscribeddirectlyfromgenome-lengthnegativestrands.Itwasbasedonthefailuretofindincoronavi

4、rusinfectedcellssubgenome-Iengthnegativestrandsorreplicationintermediatescontainingsubgenome-lengthnegativestrands.Clearly,thesestructuresexistininfectedcellsandaretranscriptionallyactive.Weproposedanewmodelforcoronavirustranscriptionwhichwecalled3'discontinuousextensionofneg

5、ativestrands.Thismodelpredictsthatsubgenome-lengthnegativestrandswouldbederiveddi?rectlybytranscriptionusingthegenomeRNAasatemplate.Thesubgenome-lengthtem?plateswouldcontainthecommon5'leadersequenceandserveastemplatesfortheproductionofsubgenomicmRNAs.Ourfindingsincludeshowing

6、that:I.Replicationin?termediates(RIs)containingsubgenome-lengthRNAexistininfectedcellsandaresepa?rablefromRIswithgenome-lengthtemplates.TheRFswithsubgenome-lengthtemplatesarenotderivedbyRNasetreatmentofRIswithgenome-lengthtemplates.2.Thesub?genome-lengthnegativestrandsareform

7、edearlyininfectionwhenRIsareaccumulatingandtherateofviralRNAsynthesisisincreasingexponentially.3.Subgenome-Iengthnegativestrandscontainattheir3'endsacomplementarycopyofthe72nucleotideleaderRNAthatisfoundinthegenomeonlyattheir5'end.4.RIswithsubgenomictemplatesCoronavirusesandA

8、rteriviruses,editedbyEnjuanesetaf.PlenumPress,NewYork,1998215216S.G.