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在急性髓系白血病中,t(8;21)染色体易位占12%~15%,这种易位造成AML1-ETO融合蛋白.随着AML1-ETO融合蛋白在白血病中发病作用的研究进展,目前人们对ETO蛋白的功能有了深入的认识.ETO蛋白含有4个与Nervy蛋白同源的结构域(NHR1~4).其中NHR1结构域与果蝇TAF110因子同源;NHR2为二聚化结构域,并能募集mSin3A/HDAC;NHR4结构域含有2个锌指结构,它在ETO与N-CoR/SMRT/HDAC之间的相互作用中起关键作用.而有关NHR3结构域的功能尚不清楚.为了探讨NHR3结构域能否介导寡聚化,克隆并纯化了该结构域.通过分子筛凝胶排阻层析、动态光散射分析及晶体溶解后SDS-PAGE电泳,结果显示NHR3结构域是一个紧密四聚体.为研究NHR3和NHR4结构域的聚合性,克隆并纯化了NHR3+4结构域(即NHR3和NHR4结构域).通过分子筛凝胶排阻层析与蛋白非变性凝胶电泳,结果表明NHR3+4结构域在溶液中能够形成二聚体.NHR3和NHR4结构域参与寡聚化作用的生物功能可能在于:(ⅰ)以聚合体的形式募集核共抑制复合物;(ⅱ)通过NHR2,NHR3和NHR4结构域的共同作用来稳定ETO蛋白的二聚体状态,从而有利于ETO蛋白稳定募集核共抑制复合物.这些有关NHR3和NHR4结构域参与寡聚化的功能推测及在白血病中的发病作用非常值得进一步探讨.
In acute myeloid leukemia, the translocation of t (8; 21) accounts for 12% -15%, and this translocation causes AML1-ETO fusion protein.With the progress of AML1-ETO fusion protein in the pathogenesis of leukemia, At present, people have a deep understanding of the function of ETO protein, which contains four homology domains (NHR1 ~ 4) with Nervy protein, NHR1 domain is homologous with Drosophila TAF110 factor, NHR2 is dimerization structure Domain and recruits mSin3A / HDAC; the NHR4 domain contains two zinc finger structures that play key roles in the interaction between ETO and N-CoR / SMRT / HDAC, while the function of the NHR3 domain is unclear In order to investigate whether the NHR3 domain can mediate oligomerization, the domain was cloned and purified.Through molecular sieve gel exclusion chromatography, dynamic light scattering analysis and SDS-PAGE electrophoresis after the crystal was dissolved, the results showed that the NHR3 domain was A tight tetramer To investigate the polymerisation of the NHR3 and NHR4 domains, the NHR3 + 4 domains (ie, NHR3 and NHR4 domains) were cloned and purified by molecular sieve gel exclusion chromatography and protein non-denaturing gel electrophoresis , The results showed that the NHR3 + 4 domain was able to form dimers in solution.NHR3 and NHR4 domains involved The biological function of the polymerization may consist in: (i) recruiting nuclear co-repressor complexes in the form of aggregates; (ii) stabilizing the dimer state of the ETO protein by the interaction of the NHR2, NHR3 and NHR4 domains and thus Which facilitates the stable recruitment of nuclear co-repressor complexes to ETO proteins.These functional speculations on the involvement of NHR3 and NHR4 domains in oligomerization and the pathogenesis of leukemias are worthy of further exploration.