简介：SulfatecanbeactivatedbyATPsulfurylaseandadenosine5’-phosphosulfatekinase(APSK)invivo.RecentstudiessuggestedthatAPSKinArabidopsisthalianaregulatedthepartitionbetweenAPSreductionandphosphorylationanditsactivitycanbemodulatedbycellularredoxstatus.InordertostudyregulationofAPSKinrice(OsAPSK),OsAPSK1genewasclonedanditsactivitywasanalyzed.OsAPSK1C36andC69werefoundtobetheconservedcounterpartsofC86andC119,whichinvolvedindisulfideformationinAtAPSK.C36A/C69AOsAPSK1doublemutationwasmadebysitedirectedmutagenesis.OsAPSK1anditsmutantwereprokaryoticallyover-expressedandpurified,andthenassayedforAPSphosphorylationactivity.OsAPSK1activitywasdepressedbyoxidizedglutathione,whiletheactivityofitsmutantwasnot.Furtherstudiesinthecasethatoxidativestresswillfluctuateinvivo3’-phosphoadenosine-5’-phosphosulfatecontent,andallAPSKisoenzymeshavesimilarregulationpatternsarenecessarytobeperformed.

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简介：Riceblack-streakeddwarfvirus(RBSDV)isarecognizedmemberofthegenusFijivirus,familyReoviridae.Itsgenomehastendouble-strandedRNA(dsRNA)segments(S1-S10),inwhichthefifthgenomesegment(S5)containstwoopenreadingframes(ORFs)withapartiallyoverlappingregion.ThesecondORFofRBSDVS5encodesaviralnonstructuralproteinnamedp5bwithunknownfunction.Torevealthefunctionofp5b,itsgenewasligatedintothebaitplasmidpGBKT7andanexpressionlibrarycontainingricecDNAswasconstructedusingplasmidpGADT7foryeasttwo-hybridassay.Thebaitproteinp5bwasdetectedinyeastbywesternblot,andtheresultofanauto-activationtestshowedthatp5bcouldnotautonomouslyactivatetheexpressionofreportergenesinyeast.Thenthebaitproteinp5bwasusedforscreeningthecDNAexpressionlibrariesofrice.Genefragmentsofsomepivotalenzymesinvolvedinphotosynthesis,respirationandotherimportantmetabolicprocesses,wereidentifiedtointeractwithp5binyeast,suggestingthattheseinteractionsmayplayrolesinsymptomdevelopmentininfectedplants.

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