Fackelmayer F O, Dahm K, Renz A, Ramsperger U, Richter A
Department of Biology, University of Konstanz, Germany.
Eur J Biochem. 1994 Apr 15;221(2):749-57. doi: 10.1111/j.1432-1033.1994.tb18788.x.
We show that SAF-A, a nuclear protein which specifically binds vertebrate scaffold-attachment-region (SAR) elements with high affinity is identical with hnRNP-U, assumed to be involved in packaging of hnRNA in ribonucleoprotein particles. Ultraviolet cross-linking experiments show that the protein, referred to as hnRNP-U/SAF-A, is bound to chromosomal DNA in vivo. In vitro, the isolated protein binds to double-stranded and single-stranded DNA and forms higher ordered nucleic-acid-protein complexes. Filter-binding experiments performed with different types of natural and synthetic nucleic acids as substrates show that the protein binds DNA and RNA with different affinities and most likely at different binding sites. We conclude that hnRNP-U/SAF-A thus may have functions in the organisation of chromosomal DNA in addition to its suggested role in hnRNA metabolism.
我们发现，SAF-A是一种核蛋白，它能以高亲和力特异性结合脊椎动物支架附着区域（SAR）元件，与假定参与核内不均一RNA（hnRNA）包装到核糖核蛋白颗粒过程的hnRNP-U相同。紫外线交联实验表明，这种被称为hnRNP-U/SAF-A的蛋白质在体内与染色体DNA结合。在体外，分离出的蛋白质能与双链和单链DNA结合，并形成更高级别的核酸-蛋白质复合物。以不同类型的天然和合成核酸为底物进行的滤膜结合实验表明，该蛋白质以不同亲和力结合DNA和RNA，且很可能结合于不同位点。我们得出结论，hnRNP-U/SAF-A除了在hnRNA代谢中所暗示的作用外，可能在染色体DNA的组织中也具有功能。
