• Animal cells and systems
• /
• v.10 no.1
• /
• pp.1-6
• /
• 2006

Previous studies showed that Cdc7 kinase of Schizosaccharomyces pombe phosphorylated the minichromosome maintenance (Mcm) complex efficiently in the presence of spMcm10 protein. The biochemical properties of the phosphorylated Mcm complexes were examined to understand the activation mechanism of the Mcm complex by Cdc7 kinase. The phosphorylation of Mcm complex in the presence of spMcm10 by Cdc7 kinase did not affect the stability of the Mcm complex containing all six subunits, and the changes in the sedimentation properties were not observed after the phosphorylation. The reconstitution of the Mcm complex using the purified proteins showed that the phosphorylation of Mcm2 proteins did not affect the interactions between Mcm proteins. The phosphorylation of the Mcm2-7 complex at the same condition also did not activate the other biochemical activities such as DNA helicase and single stranded (ss) DNA binding activities. On the other hand, spMcm10 protein that was used for the stimulation of Mcm phosphorylation showed single stranded DNA binding activity, and inhibited the DNA helicase activity of the Mcm4/6/7 complex. These inhibitory effects were reduced by the addition of Cdc7 kinase, suggesting that the phosphorylation by Cdc7 kinase decreased the interactions between spMcm10 and the Mcm complex. Taken together, these results suggested that the phosphorylation by Cdc7 kinase alone is not sufficient for the remodeling and the activation of the Mcm complex, and the additional factors or the phosphorylations might be required for the activation of the Mcm complex.

• Journal of Life Science
• /
• v.14 no.5
• /
• pp.732-740
• /
• 2004

MCM proteins are essential for eukaryotic DNA replication, playing roles in the initiation and elongation of DNA replication. MCM proteins expression is much higher in malignant tissues than normal tissues. Several reports have indicated the usefulness of MCM proteins as markers of cancer cells in histopathological diagnosis. However, the cause of enhanced expression of MCM proteins in cancer cells remain to be clarified. The purpose of this study is to examine the relative transcriptional activities of human mcm gene promoters in cancer and normal cells. The minimal promoter region required for transcription of a luciferase reporter gene was contained an E-box and one E2F site. In addition, luciferase activities from mcm7 and mcm2 promoter/luciferase gene reporter constructs were significantly increased in cancer cells at 8 times compared with normal cells. E-box and E2F binding site in the promoter of mcm genes are responsible for different mechanism of transcription regulation on the cellular environment.

• Journal of Microbiology and Biotechnology
• /
• v.32 no.7
• /
• pp.918-926
• /
• 2022

Proteins related to DNA replication have been proposed as cancer biomarkers and targets for anticancer agents. Among them, minichromosome maintenance (MCM) proteins, often overexpressed in various cancer cells, are recognized both as notable biomarkers for cancer diagnosis and as targets for cancer treatment. Here, we investigated the activity of cedrol, a single compound isolated from Juniperus chinensis, in reducing the expression of MCM proteins in human lung carcinoma A549 cells. Remarkably, cedrol also strongly inhibited the expression of all other MCM protein family members in A549 cells. Moreover, cedrol treatment reduced cell viability in A549 cells, accompanied by cell cycle arrest at the G1 phase, and enhanced apoptosis. Taken together, this study broadens our understanding of how cedrol executes its anticancer activity while demonstrating that cedrol has potential application in the treatment of human lung cancer as an inhibitor of MCM proteins.

• Animal cells and systems
• /
• v.11 no.2
• /
• pp.129-134
• /
• 2007

The initiation of eukaryotic DNA replication requires assembly of the pre-replicative complex (Pre-RC) through the concerted action of Orc, Cdc6, Cdt1 and Mcm2-7 complex during G1 phase. The pre-RC assembly licenses individual replication origins for the initiation of DNA replication and sufficient number of the pre-RC is essential for proper progression of S phase. However, it is not well known how cells recognize the completion of the pre-RC assembly before G1-S transition. In order to understand the cellular responses to the defects in pre-RC assembly, we depleted the known components of pre-RC proteins using the small interference RNAs in HeLa cells. Although the defects of pre-RC assembly by the depletion of the pre-RC proteins such as Orc2, Cdt1, Mcm2 & Mcm10 did not elicit the activation of Chk1- or Chk2-dependent checkpoint pathways, these cells still showed significant decrease in the cellular level of Cdc25A proteins. These results suggests that a novel checkpoint pathway exist in HeLa cells, which is not dependent upon Chk1 or Chk2 proteins and play essential roles in the cellular responses to the defects in the pre-RC assembly. Also, among those four proteins tested in this study, the depletion of Mcm10 and Cdt1 proteins significantly increased the apoptotic cell death in HeLa cells, suggesting that these proteins not only play roles in the pre-RC assembly, but also are involved in the checkpoint responses to the defects in the pre-RC assembly.

• The Korean Journal of Zoology
• /
• v.29 no.4
• /
• pp.294-306
• /
• 1986

In order to find out whether myoblast cells release into the culture medium any substances that induce or promote the fusion of myoblasts, chick embryonic myoblasts were cultured and the cultured medium (muscle-conditioned medium, MCM) was collected. The MCM was then added to the newly cultured myoblasts to examine if it has fusion-promoting activity. The MCM was also analyzed for its protein content before and after its addition to the second culture. The MCM apparently showed fusion-promoting activity when applied to unfused young myoblasts, suggesting that it contained substances that promote the fusion and that had been released from cells fo the previous culture. Analysis of proteins in the myoblasts and in the MCM suggested that the released protein was absorbed by or tightly bound to myoblasts of the second culture. One of the released proteins of about 175 kilodalton was degraded to a polypeptide of approximately 145 kilodalton, which appeared to act upon the membrane proteins of unfused myoblasts so as to stimulate their membrane to fuse with neighboring cells.

• The Korean Journal of Zoology
• /
• v.27 no.3
• /
• pp.151-164
• /
• 1984

In order to investigate the mechanism of myoblast fusion during muscle differentiation in culture, the effect of muscle-conditioned medium on the fusion was studied and possible release from cultured myoblast cells of proteins which may be responsible for the promotion of myoblast fusion was analyzed. The muscle-conditioned medium showed a marked fusion-promoting activity in a dose-dependent fashion. THis fusion-promoting activity of the muscle-conditioned medium appeared to be due to the accumulation of at least two proteins which were released from the myoblast into the culture medium. These released proteins were analyzed by electrophoresis and autoradiography and found to have molecular weights of 45,000 and 65,000.

• Proceedings of the Zoological Society Korea Conference
• /
• 1998.10b
• /
• pp.337.1-337
• /
• 1998

No Abstract, See Full Text

• Biomedical Science Letters
• /
• v.23 no.4
• /
• pp.372-379
• /
• 2017

This study was investigated to test whether paternal DNA that was destined for degradation was properly licensed by testing for the presence of mini-chromosome maintenance protein (MCM) 7 and origin recognition complex (ORC) 2 in the paternal pronuclei. ORC2 is one of the first licensing protein to come on and MCM7 is one of the last licensing protein to come on. Zygotes were prepared by injection of control and treated sperm injection (ICSI). To control for DNA breakage, epididymal spermatozoa were treated with DNase I to fragment the DNA, then injected into oocytes. The presence of MCM7 and ORC2 in the pronuclei of mouse zygotes was tested by immunohistochemistry, just before the onset of DNA synthesis, at 5 h after fertilization, and after DNA synthesis began, at 9 h post fertilization. We found that in all cases, both MCM7 and ORC2 were present in both pronuclei at 5 h after sperm injection, just before DNA synthesis began. This indicates that no matter how extensive the DNA damage, recruitment of licensing proteins to the origins of replication was not inhibited. Sperm DNA fragmentation does not prevent licensing of DNA replication origins. Furthermore, the embryo recognizes DNA that is damaged by nucleases. Our data indicate that the one-cell embryo does harbor a mechanism to prevent the replication of severely damaged DNA from spermatozoa, even though the embryos do not undergo classical apoptosis.

• Korean Journal of Food Science and Technology
• /
• v.42 no.1
• /
• pp.82-89
• /
• 2010

To obtain functional materials from a submerged culture of Hericium erinaceum, a suitable basal medium for flask culture was screened and the optimal culture conditions in a jar fermenter were investigated with the addition of ginseng extracts (GE) to the basal liquid medium. Of all tested basal liquid media, the mushroom complete medium (MCM) supplemented with 0.5% of GE produced the highest mycelial dry weight (MDW) of 5.91 g/L in the flask, which reached a plateau at $25^{\circ}C$, pH 5.5 after 10 days. The submerged culture conditions for the mass production of mycelia in a 50 L jar fermenter were also optimal at $25^{\circ}C$, pH 5.5, 120 rpm agitation speed and 0.4 vvm aeration rate. Under these conditions, the maximum MDW was produced, which reached a value of 4.28 g/L within 5 days. When we investigated the effects of the amount of GE in the MCM on the production of MDW in the jar fermenter, the addition of 5% GE (HE-GE-5) under the optimal culture conditions produced the maximum MDW (4.93 g/L). In addition, the crude polysaccharide of HE-GE-5 contained mainly neutral sugars (63.2%) with considerable amounts of uronic acid (19.3%) and a small amount of proteins (8.8%) and it had potent immunostimulation properties.

• Genomics & Informatics
• /
• v.8 no.1
• /
• pp.34-40
• /
• 2010

Radiofrequency (RF) radiation might induce the transcription of a certain set of genes as other physical stresses like ionizing radiation and UV. To observe transcriptional changes upon RF radiation, we exposed WI-38, human lung fibroblast cell to 1763 MHz of mobile phone RF radiation at 60 W/kg of specific absorption rate (SAR) for 24h with or without heat control. There were no significant changes in cell numbers and morphology after exposure to RF radiation. Using quantitative RT-PCR, we checked the expression of three heat shock protein (HSP) (HSPA1A, HSPA6 and HSP105) and seven stress-related genes (TNFRSF11B, FGF2, TGFB2, ITGA2, BRIP1, EXO1, and MCM10) in RF only and RF/HS groups of RF-exposed cells. The expressions of three heat shock proteins and seven stress-related genes were selectively changed only in RF/HS groups. Based on the expression of ten genes, we could classify thermal and non-thermal effect of RF-exposure, which genes can be used as biomarkers for RF radiation exposure.