Subramaniam A, Thirunavukkarasu M, Rajamanickam C
Department of Biochemistry, School of Biological Sciences, Madurai Kamaraj University, Tamil Nadu, India.
Biochem J. 1990 Apr 1;267(1):133-40. doi: 10.1042/bj2670133.
The 100,000 g supernatant isolated from hypertrophic hearts on fractionation by (NH4)2SO4 and DEAE-cellulose chromatography showed an enhanced RNA-transport activity when incubated with isolated nuclei from sham-operated hearts in vitro. Proteins of Mr 73,000, 68,000, 43,000 and 32,000 are enriched in the DEAE-cellulose fractions exhibiting maximal transport activity, and they are phosphorylatable. Pretreatment of the cytosol with antibodies to the Mr-68,000 and -32,000 proteins decreases the transport activity of the cytosol from 14% to 4.25%. Proteins of Mr 73,000, 68,000, 43,000 and 32,000 are translocated from the cytosol to the nuclear envelope under conditions of RNA transport in vitro. Our results here suggest that at least two of these proteins, those of Mr 68,000 and 32,000, play an indispensible role in the nucleocytoplasmic RNA transport in vitro. By making use of a specific myosin heavy-chain B-gene probe and hybridization, we have also shown the effect of cytosol on the transport of myosin heavy-chain mRNA from nucleus to cytosol.
从肥大心脏中分离出的100,000g上清液，经硫酸铵分级分离和DEAE - 纤维素色谱法处理后，当与假手术心脏分离出的细胞核在体外孵育时，显示出增强的RNA转运活性。Mr 73,000、68,000、43,000和32,000的蛋白质在表现出最大转运活性的DEAE - 纤维素级分中富集，并且它们是可磷酸化的。用针对Mr - 68,000和 - 32,000蛋白质的抗体预处理细胞质，可使细胞质的转运活性从14%降至4.25%。在体外RNA转运条件下，Mr 73,000、68,000、43,000和32,000的蛋白质从细胞质转运至核膜。我们这里的结果表明，这些蛋白质中至少有两种，即Mr 68,000和32,000的蛋白质，在体外核质RNA转运中起不可或缺的作用。通过使用特异性肌球蛋白重链B基因探针和杂交技术，我们还展示了细胞质对肌球蛋白重链mRNA从细胞核向细胞质转运的影响。
