Biological Institute, Faculty of Science, Tohoku University, Sendai, 980, Japan.
Plant Physiol. 1989 Mar;89(3):910-7. doi: 10.1104/pp.89.3.910.
This study shows an overall analysis of gene expression during the cell cycle in synchronous suspension cultures of Catharanthus roseus cells. First, the cellular cytoplasmic proteins were fractionated by two-dimensional gel electrophoresis and visualized by staining with silver. Seventeen polypeptides showed qualitative or quantitative changes during the cell cycle. Second, the rates of synthesis of cytoplasmic proteins were also investigated by autoradiography by labeling cells with [(35)S]methionine at each phase of the cell cycle. The rates of synthesis of 13 polypeptides were found to vary during the cell cycle. The silverstained electrophoretic pattern of proteins in the G(2) phase in particular showed characteristic changes in levels of polypeptides, while the rates of synthesis of polypeptides synthesized during the G(2) phase did not show such phase-specific changes. This result suggests that posttranslational processing of polypeptides occurs during or prior to the G(2) phase. In the G(1) and S phases and during cytokinesis, several other polypeptides were specifically synthesized. Finally, the variation of mRNAs was analyzed from the autoradiograms of in vitro translation products of poly(A)(+) RNA isolated at each phase. Three poly(A)(+) RNAs increased in amount from the G(1) to the S phase and one poly (A)(+) RNA increased preferentially from the G(2) phase to cytokinesis.
本研究对长春花悬浮细胞同步培养过程中的细胞周期内基因表达进行了全面分析。首先，通过二维凝胶电泳将细胞胞质蛋白进行分离，并用银染显色。在细胞周期中，有 17 种多肽表现出定性或定量的变化。其次，通过用 [(35)S]甲硫氨酸标记细胞，在每个细胞周期阶段进行放射自显影，研究了胞质蛋白的合成速率。发现 13 种多肽的合成速率在细胞周期中发生变化。特别是 G2 期蛋白的银染电泳图谱显示出多肽水平的特征性变化，而在 G2 期合成的多肽的合成速率并没有表现出这种特定的相位变化。这一结果表明，多肽的翻译后加工发生在 G2 期或之前。在 G1 和 S 期以及胞质分裂期间，还特异性合成了其他几种多肽。最后，从每个阶段分离的 poly(A)(+)RNA 的体外翻译产物的放射自显影图谱分析了 mRNA 的变化。三种 poly(A)(+)RNA 从 G1 期到 S 期的量增加，一种 poly(A)(+)RNA 从 G2 期到胞质分裂期优先增加。
