BackgroundInformation | PMLproteinisatripartitemotif(TRIM)-containingnuclearproteinthatmayfunctionas,amongotherthings,atranscriptionfactor,acoactivatorofnuclearreceptors(Ruggerio,2000),aregulatorofapoptosis(Guo,2000),amediatorofinterferon-inducedantiviralresponse(RegandandChelbi-Aliz,2001),andasasuppressorofgrowthandoncogenictransformation(Mu,1997).PMLislocalizedtothenucleoplasmandindistinctsubnuclearstructuresreferredtoasPromyelocyticLeukemiaBodies(alsoknownasNuclearDomain10).LocalizationofPMLtoPromyelocyticLeukemiaBodiesrequiresmodificationofPMLproteinbytheSmallUbiquitinModifier(SUMO)andisrequiredforproperformationandintegrityofthesesubnuclearstructures.Atleast14splicevariantsofPMLranginginmolecularweightfrom48-97kDa(predicted)havebeendescribedintheliterature.Thefunctionalsignificanceofthevarioussplicevariantsisnotwellunderstood.InpatientswithAcutePromyelocyticLeukemia,thePMLgeneisinvolvedinatleasttwospecificchromosomaltranslocationsthatresultintheexpressionofchimericproteinswiththeRetinoicAcidReceptoralpha(RARalphaDNA-andHormone-bindingdomains;Pandolfi,2001).AllisoformsofPML,aswellasthePML-RARalphachimericproteinsexpressedinTypeAandTypeBAPLcontainanidenticalN-terminusbutvaryintheC-terminalportionoftheprotein(Jenson,2001). |