Gerasimenko O V, Gerasimenko J V, Tepikin A V, Petersen O H
Physiological Laboratory, University of Liverpool, England.
Cell. 1995 Feb 10;80(3):439-44. doi: 10.1016/0092-8674(95)90494-8.
Uptake and release of Ca2+ from isolated liver nuclei were studied with fluorescent probes. We show with the help of digital imaging and confocal microscopy that the Ca(2+)-sensitive fluorescent probe Fura 2 is concentrated in or around the nuclear envelope and that the distribution of Fura 2 fluorescence is similar to that of an endoplasmic reticulum marker. The previously demonstrated ATP-dependent uptake of Ca2+ into isolated nuclei and release of the accumulated Ca2+ by inositol 1,4,5-trisphosphate (IP3) are therefore due to transport of Ca2+ into and out of the nuclear envelope and not the nucleoplasm. Dextrans labeled with fluorescent Ca2+ indicators (calcium-Green 1 and Fura 2) are distributed uniformly in the nucleoplasm and can be used to show that changes in the external Ca2+ concentration produce rapid changes in the nucleoplasmic Ca2+ concentration. Nevertheless, IP3 and cyclic ADP-ribose evoke transient intranuclear Ca2+ elevations. The release from the Ca2+ stores in or around the nuclear envelope appears to be directed into the nucleoplasm from where it can diffuse out through the permeable nuclear pore complexes.
利用荧光探针研究了分离的肝细胞核对Ca2+的摄取和释放。我们借助数字成像和共聚焦显微镜表明，Ca(2+)敏感荧光探针Fura 2集中在核膜内或核膜周围，且Fura 2荧光的分布与内质网标记物的分布相似。因此，先前证明的Ca2+依赖ATP摄取到分离的细胞核中以及由肌醇1,4,5-三磷酸（IP3）释放积累的Ca2+，是由于Ca2+进出核膜的运输，而非核质的运输。用荧光Ca2+指示剂（钙绿1和Fura 2）标记的葡聚糖在核质中均匀分布，可用于表明细胞外Ca2+浓度的变化会导致核质Ca2+浓度的快速变化。然而，IP3和环ADP-核糖会引起核内Ca2+的瞬时升高。核膜内或核膜周围Ca2+储存库的释放似乎是直接进入核质，然后从那里通过可渗透的核孔复合体扩散出去。
