Phase-Specific Polypeptides and Poly(A)⁺ RNAs during the Cell Cycle in Synchronous Cultures of Catharanthus roseus Cells

Abstract

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 quantitafive changes during the cell cycle. Second, the rates of synthesis of cytoplasmic proteins were also investigated by autoradiography by labeling cells with [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 pattem of proteins in the G2 phase in particular showed characteristic changes in levels of polypeptides, while the rates of synthesis of polypeptides synthesized during the G2 phase did not show such phase-specific changes.This result suggests that posttranslational processing of polypeptides occurs during or prior to the G2 phase. In the G1 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 translafton products of poly(A)+ RNA isolated at each phase. Three poly(A)+ RNAs increased in amount from the GI to the S phase and one poly (A)+ RNA increased preferentially from the G2 phase to cytokinesis.The cell cycle in eukaryotes consists of an ordered sequence of events, which include DNA synthesis, replication of organelles, and mitosis, and which are controlled by the ordered expression of genes. Many studies have been undertaken to examine the changes in protein patterns through which the sequential action of genes during the cell cycle is reflected, and to demonstrate that genes involved in cell proliferation are expressed transiently during the cell cycle. Two-dimensional gel electrophoresis has revealed the presence of several phase-specific proteins in mammalian cells which appear in the G2 phase (1) or which are synthesized in the S phase (10) and the G2/M phase (41). There are also reports (8,15,29) that no unique proteins are synthesized during the cell cycle in HeLa cells and yeast.

Identification of Proliferation-Induced Genes in Arabidopsis thaliana (Characterization of a New Member of the Highly Evolutionarily Conserved Histone H2A.F/Z Variant Subfamily)

“…These results appear to be in agreement with those previously obtained in Catkaruntkus roseus (Kodama et al, 1989).…”

“…Vol. 11 5,1997 at the different phases of the cell cycle (Kodama et al, 1989). Severa1 cDNA clones corresponding to genes that are preferentially expressed at the G1/S boundary of the cell cycle were isolated in this system (Kodama et al, 1991a).…”

Molecular cloning of the gene for plant proliferating‐cell nuclear antigen and expression of this gene during the cell cycle in synchronized cultures of Catharanthus roseus cells

“…were used and a cDNA library was constructed from poly(A)-rich RNA isolated from the cells of strain B in the S phase. Previous investigations on the cell cycle have been performed with strain B (Kodama et al, 1989(Kodama et al, ,1991. In addition, another strain (TN21) was used.…”

“…Therefore, this system is suitable for analysis of genes involved in DNA replication which are considered to express transiently at the Gl/S boundary. Using this system, several investigations have been performed concerning the alterations of gene expression during the cell cycle (Kodama et al, 1989(Kodama et al, , 1991.…”

Isolation and Characterization of a cDNA Clone for Plant Nuclear Antigen 21D7 Associated with Cell Division

“…were used. Cultivation of strain B was performed as described by Amino et al (1983) and by Kodama et al (1989); initiation and cultivation of the second strain, TN21, is described in detail by Nishida et al (1992). These strains have been maintained at 27OC in the dark in Murashige-Skoog medium with 3% (w/v) Suc supplemented with 2.2 X 10-6 or 4.4 X 10T6 M 2,4-D for strain B or strain TNZI, respectively.…”