Michaud N, Goldfarb D S
Department of Biology, University of Rochester, New York 14627.
Exp Cell Res. 1993 Sep;208(1):128-36. doi: 10.1006/excr.1993.1230.
Using kinetic competition analysis, we show that the import of most Xenopus oocyte nuclear proteins is directed by a single family of nuclear localization signals (NLS). The transport of microinjected [35S]methionine-labeled nuclear proteins into oocyte nuclei was challenged with saturating concentrations of SV40 large T-antigen NLS peptide-BSA (P(Lys)-BSA) and was assessed by SDS-acrylamide gel electrophoresis and fluorography. P(Lys)-BSA was effective at competing the import of virtually all larger polypeptides but had a less marked effect on the mediated import of many smaller polypeptides. Wheat germ agglutinin, an inhibitor of nuclear pore complex function, enhanced the competitive effects of P(Lys)-BSA on the import of both large and small polypeptides. These data indicate that most 35S-labeled Xenopus oocyte nuclear proteins, including nucleoplasmin, contain NLSs that are functionally related to the T-antigen NLS and probably employ the same cytosolic NLS receptor(s).
通过动力学竞争分析，我们发现大多数非洲爪蟾卵母细胞核蛋白的输入是由单一的核定位信号（NLS）家族指导的。用饱和浓度的SV40大T抗原NLS肽 - 牛血清白蛋白（P（Lys）-BSA）挑战显微注射的[35S]甲硫氨酸标记的核蛋白向卵母细胞核的转运，并通过SDS - 丙烯酰胺凝胶电泳和荧光自显影进行评估。P（Lys）-BSA在竞争几乎所有较大多肽的输入方面有效，但对许多较小多肽的介导输入影响较小。小麦胚凝集素是核孔复合体功能的抑制剂，增强了P（Lys）-BSA对大小多肽输入的竞争作用。这些数据表明，大多数35S标记的非洲爪蟾卵母细胞核蛋白，包括核质蛋白，都含有与T抗原NLS功能相关的NLS，并且可能使用相同的胞质NLS受体。
