Bader T, Weitzerbin J
Unité 365 Institut National de la Santé et de la Recherche Médicale, Interférons et Cytokines, Institut Curie, Paris, France.
Proc Natl Acad Sci U S A. 1994 Dec 6;91(25):11831-5. doi: 10.1073/pnas.91.25.11831.
Examination of the interferon gamma (IFN-gamma) amino acid sequence revealed two conserved basic amino acid clusters similar to the prototype nuclear localization signal. We followed the fate of cell surface receptor-bound IFN-gamma in murine leukemia L1210 cells. A time- and temperature-dependent accumulation of murine IFN-gamma in the cell nucleus could be demonstrated by autoradiography and indirect immunofluorescence after the rapid isolation of nuclei. Human IFN-gamma was also internalized and translocated to the nucleus of murine L1210 cells transfected with and expressing the human IFN-gamma receptor, but it appeared to be retained by the nucleus only transiently. IFN-gamma molecules chemically crosslinked to their cell surface receptor remain capable of being translocated to the nucleus even as part of a receptor-ligand complex. Thus, the bipartite nuclear localization signal sequence appears to be functional and suggests that nuclear targeting could participate in IFN-gamma signal transduction.
对干扰素γ（IFN-γ）氨基酸序列的检查发现了两个与典型核定位信号相似的保守碱性氨基酸簇。我们追踪了小鼠白血病L1210细胞中细胞表面受体结合的IFN-γ的命运。在快速分离细胞核后，通过放射自显影和间接免疫荧光可以证明小鼠IFN-γ在细胞核中呈时间和温度依赖性积累。人IFN-γ也被内化并转运到转染并表达人IFN-γ受体的小鼠L1210细胞的细胞核中，但它似乎只是短暂地被细胞核保留。化学交联到其细胞表面受体的IFN-γ分子即使作为受体-配体复合物的一部分，仍能够转运到细胞核。因此，二分核定位信号序列似乎具有功能，这表明核靶向可能参与IFN-γ信号转导。
