帮我做一题分子生物学题目?我会再申几个号给你加分的!
YouhaveisolatedanewstrainofanE.coli-likebacteriafromhospitalpatients.Uponsequencingthegenome,youdiscoverthatthisbacteriahasagroupofabout30genes,absentfromthestandardlabstrains,thatyoususpectareinvolvedinpathogenesis(发病机理).Youinitiateaprojecttounderstandtheexpressionandfunctionofthesegenes.
BycomparingmRNAsizeswiththeDNAsequence,yourealizethatoneofthesegenes,pukC,appearstocontainanintron.Sincebacterialackthespliceosomecomponentsfoundinhighercells,youhypothesizethatyouhaveisolatedanewself-splicingintron.
SequenceanalysisofthepukCintronfailedtorevealclearhomologytoeitherthegroupIorgroup2self-splicingintronfamilies.
TostudythemechanismofsplicingyouclonethepukCgeneontoaplasmidbehindagoodpromoter.ThisconstructallowsyoutosynthesizethepukCpre-mRNAusinginvitrotranscription.Whenyouruntheproductsofthisfirsttranscriptionexperimentonagel,youseeRNAmoleculeswithlengthssuggestingthatsplicingisoccurring(althoughveryslowly)duringthetranscriptionreactions.
Question1:Giventhisresult,suggestamodificationoftheinvitro
reactionusedabovethatcouldgiveaquickindicationofwhetherthepukCintronusesamechanismsimilartothegroupIorsimilartothegroupIIintrons.
Question2:Nowdescribeamoredefinitiveexperimentthatwillallow
youtoshowthatthepukCintronuseseitheragroupIorgroupII-like
mechanism.Whatresultsdoyouexpecttoobserveforeachofthetwo
mechanisms?
可以用汉语吗?我看不懂这个!