简介：AktandBcl-xLbothpromoteresistancetoapoptosis.AcomparisonofAkt-andBcl-xL-dependentcellsurvivalwasundertaken.ExpressionofconstitutivelyactiveAktallowscellstosurviveforprolongedperiodsintheabsenceofgrowthfactors.ThissurvivalcorrelateswiththeexpressionlevelofactivatedAktandiscomparableinmagnitudetotheprotectionprovidedbytheanti-apoptoticgeneBcl-xL.Althoughbothgenespreventcelldeath,Akt-protectedcellscanbedistinguishedfromBcl-xL-protectedcellsonthebasisofincreasedglucosetransporterexpression,glycolyticactivity,mitochondrialpotential,andcellsize.Inaddition,Akt-expressingcellsrequirehighlevelsofextracellularnutrientstosupportcellsurvival.In

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简介：ThesplicingofmanyalternativeexonsintheprecursormessengerRNA(pre-mRNA)isregulatedbyextracellularfactorsbuttheunderlyingmolecularbasesremainunclear.HerewereportthedifferentialregulationofBcl-xpre-mRNAsplicingbyextracellularfactorsandtheirdistinctrequirementsforpre-mRNAelements.InK562leukemiacells,treatmentwithinterleukin-6(IL-6)orgranulocyte-macrophagecolonystimulatingfactor(GM-CSF)reducedtheproportionoftheBcl-xLvariantmRNAwhiletreatmentwith12-O-tetradecanoylphorbol13-acetate(TPA)hadnoeffect.InU251gliomacells,however,TPAefficientlyincreasedtheBcl-xLlevel.Theseregulationswerealsoseenforatransfectedsplicingreportermini-gene.Furtheranalysesofdeletionmutantsindicatethatnucleotides1-176ofthedownstreamintronarerequiredfortheIL-6effect,whereasadditionalnucleotides177-284areessentialfortheGM-CSFeffect.AsfortheTPAeffect,onlynucleotides1-76arerequiredinthedownstreamintron.Thus,IL-6,GM-CSFandTPAdifferentiallyregulateBcl-xsplicingandrequirespecificintronicpre-mRNAsequencesfortheirrespectiveeffects.

简介：用PCR技术获得抗菌肽-X基因、TNFα基因,与温度诱导的表达载体pRC连接成为重组表达载体,导入大肠杆菌TG1,通过温度诱导表达重组蛋白.将重组质粒转入不同的表达菌中进行表达,经SDS-PAGE选出EcoliBL21(DE3)为最佳表达的宿主菌.培养后,离心得菌体,经超声破碎离心得包涵体,溶解后用CNBr切割并透析,最后经CM52纤维素柱分离纯化得到有活性高纯度的抗菌肽-X.

简介：比利时科学家近日将生命衰老与基因之间关系的研究范围缩小，并于2004年2月14日表示，生命衰老与X染色体存在关联。