简介：heterotrimericguanine核苷酸绑定蛋白质(G蛋白质)被表明了各种各样的发信号调停在植物的小径。然而，它在发信号的phytochromeA(phyA)的角色留下逃犯。在这研究，我们发现新调停phyA的显型指明了far-red照耀(FR)preconditioned房间死亡，它仅仅在跟随暴露到白光(WL)的FR-grown幼苗的胚轴发生。房间死亡在G变异的gpa1被减轻，但是与野类型(WT)比较在G变异的agb1加重了，在调停phyA的房间死亡小径的GPA1和AGB1的对抗角色的陈述语气。进一步的调查显示nonphotoconvertibleprotochlorophyllide(Pchlide633)的导致FR的累积，在暴露上产生反应的氧种类(ROS)到WL，为前提FR的房间死亡被要求。而且，ROS主要在叶绿体被检测用荧光灯探查。有趣地，到黑暗成年的幼苗的H2O2的申请导致类似于前提FR的房间死亡的显型。这表明ROS是为房间死亡的一个批评调停人。另外，我们观察到agb1比WT幼苗对H2O2更敏感，显示G蛋白质可以也修改到ROS应力的幼苗的敏感。一起拿这些结果，我们推断G蛋白质可以涉及表明小径调整Arabidopsis胚轴的前提FR的房间死亡的phyA。在phyA位于G蛋白质的参与下面发信号的可能的机制在这研究被讨论。

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简介：Thenon-classicalHLAclassIantigenHLA-GisanimmunemodulatorwhichinhibitsthefunctionsofTcells,NKcells,andtheDendriticcells(DC).Asaresult,HLA-Gexpressioninmalignantcellsmayprovidethemwithamechanismtoescapetheimmunesurveillance.Inmelanoma,HLA-Gantigenexpressionhasbeenfoundin30%ofsurgicallyremovedlesionsbutinlessthan1%ofestablishedcelllines.OnepossiblemechanismunderlyingthedifferentialHLAGexpressioninvivoandinvitroisthattheHLA-Ggeneisepigeneticallyrepressedinmelanomacellsinvitro.Totestthishypothesis,wetreatedtheHLA-GnegativemelanomacelllineOCM-1AwiththeDNAmethyltransferaseinhibitor5-aza-2'-deoxycytidine(5-AC)andanalyzedwhetherHLA-Gexpressioncanberestored.OurdatastronglysuggestthatHLA-GissilencedasaresultofCpGhypermethylationwithina5'regulatoryregionencompassing220bpupstreamofthestartcodon.Aftertreatment,HLA-GmRNAexpressionwasdramaticallyincreased.WesternblotandflowcytometryshowedthatHLA-Gproteinwasinduced.Interestingly,HLA-Gcellsurfaceexpressiononthe5-ACtreatedOCM-1AcellsismuchlessthanthatontheHLA-GpositiveJEG-3cellswhileasimilaramountoftotalHLA-Gwasobserved.Possiblemechanismsforthedifferencewereanalyzedinthestudysuchascellcold-treatment,peptideloadingandantigenprocessingmachinerycomponents(APM)aswellasβ2microglobulin(β2-m)expression.DatarevealedthattheAPMcomponentcalreticulinmightbeinvolvedinthelowerHLA-GsurfaceexpressiononOCM-1Acells.Takentogether,ourresultsindicatedthatDNAmethylationisanimportantepigeneticmechanismbywhichHLA-Gantigenexpressionismodulatedinmelanomacellsinvitro.Furthermore,tothefirsttime,wehypothesizedthatthedeficiencyofcalreticulinmightbeinvolvedinthelowHLA-Gsurfaceexpressiononthe5-ACtreatedOCM-lAcells.