Guo B, Odgren P R, van Wijnen A J, Last T J, Nickerson J, Penman S, Lian J B, Stein J L, Stein G S
Department of Cell Biology, University of Masachusetts Medical Center, Worcester 01655, USA.
Proc Natl Acad Sci U S A. 1995 Nov 7;92(23):10526-30. doi: 10.1073/pnas.92.23.10526.
NMP-1 was initially identified as a nuclear matrix-associated DNA-binding factor that exhibits sequence-specific recognition for the site IV regulatory element of a histone H4 gene. This distal promoter domain is a nuclear matrix interaction site. In the present study, we show that NMP-1 is the multifunctional transcription factor YY1. Gel-shift and Western blot analyses demonstrate that NMP-1 is immunoreactive with YY1 antibody. Furthermore, purified YY1 protein specifically recognizes site IV and reconstitutes the NMP-1 complex. Western blot and gel-shift analyses indicate that YY1 is present within the nuclear matrix. In situ immunofluorescence studies show that a significant fraction of YY1 is localized in the nuclear matrix, principally but not exclusively associated with residual nucleoli. Our results confirm that NMP-1/YY1 is a ubiquitous protein that is present in both human cells and in rat osteosarcoma ROS 17/2.8 cells. The finding that NMP-1 is identical to YY1 suggests that this transcriptional regulator may mediate gene-matrix interactions. Our results are consistent with the concept that the nuclear matrix may functionally compartmentalize the eukaryotic nucleus to support regulation of gene expression.
NMP-1最初被鉴定为一种与核基质相关的DNA结合因子，它对组蛋白H4基因的IV位点调控元件表现出序列特异性识别。这个远端启动子结构域是一个核基质相互作用位点。在本研究中，我们表明NMP-1是多功能转录因子YY1。凝胶迁移和蛋白质印迹分析表明，NMP-1与YY1抗体发生免疫反应。此外，纯化的YY1蛋白特异性识别IV位点并重建NMP-1复合物。蛋白质印迹和凝胶迁移分析表明YY1存在于核基质中。原位免疫荧光研究表明，相当一部分YY1定位于核基质中，主要但并非仅与残留核仁相关。我们的结果证实NMP-1/YY1是一种普遍存在的蛋白质，存在于人类细胞和大鼠骨肉瘤ROS 17/2.8细胞中。NMP-1与YY1相同这一发现表明，这种转录调节因子可能介导基因与基质的相互作用。我们的结果与核基质可能在功能上对真核细胞核进行区室化以支持基因表达调控的概念一致。
