Bouche G, Gas N, Prats H, Baldin V, Tauber J P, Teissié J, Amalric F
Centre de Recherche de Biochimie et de Génétique Cellulaires, Centre National de la Recherche Scientifique, Toulouse, France.
Proc Natl Acad Sci U S A. 1987 Oct;84(19):6770-4. doi: 10.1073/pnas.84.19.6770.
The cellular action of growth factors, among them basic fibroblast growth factor (bFGF), is mediated by their interaction with a cell surface receptor, but the mechanism of transfer of mitogenic (or other) signals to the nucleus has not been identified. In this work, we show that bFGF is translocated to and accumulated in the nucleolus. Furthermore, the nucleolar localization of bFGF is correlated with a stimulation of transcription of ribosomal genes during G0----G1 transition induced by bFGF alone in adult bovine aortic endothelial cells (ABAE cells). Stimulation of ribosomal gene transcription is preceded by a significant increase of the major nonhistone nucleolar protein, nucleolin. In vitro, the growth factor has a direct effect on the enhancement of RNA polymerase I activity in isolated nuclei from quiescent sparse (G0) ABAE cells. The direct action of bFGF on the level of ribosomal gene transcription could correspond to an additional growth-signaling pathway, mediated by this growth factor.
生长因子（其中包括碱性成纤维细胞生长因子，即bFGF）的细胞作用是通过它们与细胞表面受体的相互作用来介导的，但是有丝分裂（或其他）信号向细胞核传递的机制尚未明确。在这项研究中，我们发现bFGF会转移至核仁并在其中积累。此外，在成年牛主动脉内皮细胞（ABAE细胞）中，仅由bFGF诱导的G0期至G1期转变过程中，bFGF的核仁定位与核糖体基因转录的刺激相关。核糖体基因转录的刺激之前，主要的非组蛋白核仁蛋白核仁素会显著增加。在体外，该生长因子对来自静止稀疏（G0期）ABAE细胞的分离细胞核中RNA聚合酶I活性的增强有直接作用。bFGF对核糖体基因转录水平的直接作用可能对应于由该生长因子介导的另一种生长信号通路。
