Lahiri D K, Thomas J O
J Biol Chem. 1985 Jan 10;260(1):598-603.
Using immunochemical techniques, we have examined the macromolecular state of association of the major heterogeneous nuclear ribonucleoprotein (hnRNP) core proteins in mitotic HeLa cells. We find that these proteins are not free but are associated with high-molecular-weight RNA in the form of particles that sediment as a broad band between 80 and 200 S. We have termed these complexes MhnRNP for mitotic hnRNP protein-containing particles. Their quantity, composition, sedimentation coefficients, buoyant density, and sensitivity to dissociating conditions suggest that they are closely related to the hnRNP complexes of interphase cells and may represent hnRNP complexes containing unprocessed or partially processed heterogeneous nuclear RNA that have been released into the cytoplasm during mitosis. Exogenously added RNA does not associate with the MhnRNP nor does it compete for the major MhnRNP proteins. The MhnRNP remain distinct from other ribonucleoprotein complexes and do not associate with ribosomes even though these structures are not separated by a nuclear envelope during mitosis.
利用免疫化学技术，我们检测了有丝分裂期HeLa细胞中主要的不均一核核糖核蛋白（hnRNP）核心蛋白的大分子缔合状态。我们发现这些蛋白并非游离状态，而是与高分子量RNA以颗粒形式结合，这些颗粒在80至200 S之间形成一条宽带沉降。我们将这些复合物称为MhnRNP，即有丝分裂期含hnRNP蛋白的颗粒。它们的数量、组成、沉降系数、浮力密度以及对解离条件的敏感性表明，它们与间期细胞的hnRNP复合物密切相关，可能代表含有未加工或部分加工的不均一核RNA的hnRNP复合物，这些复合物在有丝分裂期间释放到细胞质中。外源添加的RNA既不与MhnRNP结合，也不与主要的MhnRNP蛋白竞争。MhnRNP与其他核糖核蛋白复合物不同，即使在有丝分裂期间这些结构没有被核膜分隔开，它们也不与核糖体结合。
