Ludérus M E, den Blaauwen J L, de Smit O J, Compton D A, van Driel R
E. C. Slater Institute, University of Amsterdam, The Netherlands.
Mol Cell Biol. 1994 Sep;14(9):6297-305. doi: 10.1128/mcb.14.9.6297-6305.1994.
Chromatin in eukaryotic nuclei is thought to be partitioned into functional loop domains that are generated by the binding of defined DNA sequences, named MARs (matrix attachment regions), to the nuclear matrix. We have previously identified B-type lamins as MAR-binding matrix components (M. E. E. Ludérus, A. de Graaf, E. Mattia, J. L. den Blaauwen, M. A. Grande, L. de Jong, and R. van Driel, Cell 70:949-959, 1992). Here we show that A-type lamins and the structurally related proteins desmin and NuMA also specifically bind MARs in vitro. We studied the interaction between MARs and lamin polymers in molecular detail and found that the interaction is saturable, of high affinity, and evolutionarily conserved. Competition studies revealed the existence of two different types of interaction related to different structural features of MARs: one involving the minor groove of double-stranded MAR DNA and one involving single-stranded regions. We obtained similar results for the interaction of MARs with intact nuclear matrices from rat liver. A model in which the interaction of nuclear matrix proteins with single-stranded MAR regions serves to stabilize the transcriptionally active state of chromatin is discussed.
真核细胞核中的染色质被认为被分隔成功能环域，这些环域是由特定的DNA序列（称为MARs，即基质附着区域）与核基质结合而产生的。我们之前已将B型核纤层蛋白鉴定为与MAR结合的基质成分（M. E. E. Ludérus、A. de Graaf、E. Mattia、J. L. den Blaauwen、M. A. Grande、L. de Jong和R. van Driel，《细胞》70:949 - 959，1992年）。在此我们表明，A型核纤层蛋白以及结构相关蛋白结蛋白和核有丝分裂器蛋白在体外也能特异性结合MARs。我们从分子细节上研究了MARs与核纤层蛋白聚合物之间的相互作用，发现这种相互作用是可饱和的、具有高亲和力且在进化上保守。竞争研究揭示了与MARs不同结构特征相关的两种不同类型的相互作用：一种涉及双链MAR DNA的小沟，另一种涉及单链区域。我们对MARs与大鼠肝脏完整核基质的相互作用也得到了类似结果。本文讨论了一种模型，其中核基质蛋白与单链MAR区域的相互作用有助于稳定染色质的转录活性状态。
