• 생명과학회지
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• 제11권4호
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• pp.371-378
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• 2001

The effects of the RM 60 series on DNA replication systems were examined by using simian virus 40 (SV40) DNA replication system in vitro. The RM 60 series inhibited the DNA replication in the initiation step rather than in the elongation step. Polymerase$\alpha$-primase activity and toposiomerase I activity study were performed subsequently, the RM 60 seies increased the polymerase $\alpha$-primase activity in a low dose, but decreased the activity in a higher dose. The topoisomerase I activity was inhibited by the RM 60 series. This result suggests that the RM 60 series might inhibit some molecules which are required to establish replication forks during the initiation step of the DNA replication.

• BMB Reports
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• 제44권6호
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• pp.393-398
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• 2011

Polydnaviruses are a group of double-stranded DNA viruses and are symbiotically associated with some ichneumonoid wasps. As proviruses, the replication of polydnaviruses occurs in the female reproductive organ at the pupal stage. This study analyzed the effects of two developmental hormones, juvenile hormone (JH) and ecdysteroid, on the viral replication of Cotesia plutellae bracovirus (CpBV). All 23 CpBV segments identified contained a conserved excision/rejoining site ('AGCTTT') from their proviral segments. Using quantitative real-time PCR based on this excision/rejoining site marker, initiation of CpBV replication was determined to have occurred on day 4 on the pupal stage. Pyriproxyfen, a JH agonist, significantly inhibited adult emergence of C. plutellae, whereas RH5992, an ecdysteroid agonist, had no inhibitory effect. Although RH5992 had no effect dose on adult development, it significantly accelerated viral replication. The results of immunoblotting assays against viral coat proteins support the effects of the hormone agonists on viral replication.

• BMB Reports
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• 제28권6호
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• pp.538-545
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• 1995

When DNA replication of simian virus 40 (SV40) is initiated on the replication origin, the regions containing the initiation sites of DNA primase, which participates in the transient RNA primer synthesis for formation of Okazaki fragments in the lagging strand, were chosen as the target sites of antisense RNA for studies of the inhibition of SV40 DNA replication. Four recombinant transcription vectors, pUC-PrI, pUC-PrII, pGEM-PrBS, and pGEM-PrSN, coding antisense RNA, were constructed. Four antisense RNAs (named as I, II, BS, and SN) having the size of 18, 19,58, and 123 nts, respectively, were made from the transcription vectors by in vitro transcription. And then, antisense RNA in the concentration of 2${\mu}m$ were added to COS cells transfected with pATSV-W which is a recombinant plasmid containing the SV40 origin of replication. The inhibitory extent of DNA replication was measured by DpnI resistance and was confirmed by measurement of transient RNA primer synthesis. The result shows that six combinations of antisense RNA (I, II, BS, SN, I+SN, and BS+SN) lead to the inhibition of SV40 DNA replication by up to 85%.

• Journal of Microbiology and Biotechnology
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• 제20권8호
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• pp.1163-1178
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• 2010

Plasmids play important roles in horizontal gene transfer among Vibrionaceae, but surprisingly little is known about their replication and incompatibility systems. In this study, we successfully developed a bioinformatics-assisted strategy of experimental identification of seven Vibrio plasmid replicons. Comparative sequences analysis of the seven Vibrio plasmid replicons obtained in this study together with eight published Vibrionaceae plasmid sequences revealed replication-participating elements involved in the ColE1 mode of replication initiation and regulation. Like plasmid ColE1, these Vibrionaceae plasmids encode two RNA species (the primer RNA and the antisense RNA) for replication initiation and regulation, and as a result, the 15 Vibrionaceae plasmids were designated as ColE1-like Vibrionaceae (CLV) plasmids. Two subgroups were obtained for the 15 CLV plasmids, based on comparison of replicon organization and phylogenetic analysis of replication regions. Coexistence of CLV plasmids were demonstrated by direct sequencing analysis and Southern hybridization, strongly suggesting that the incompatibility of CLV plasmids is determined mainly by the RNA I species like the ColE1-like plasmids. Sequences resembling the conserved Xer recombination sites were also identified on the CLV plasmids, indicating that the CLV plasmids probably use the host site-specific recombination system for multimer resolution like that used by ColE1-like plasmids. All the results indicated that the 15 plasmids form a new ColE1-like group, providing a basis for the rapid characterization and classification of Vibrionaceae plasmids.

• BMB Reports
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• 제40권6호
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• pp.895-898
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• 2007

The oxygen dependent regulation of DNA replication is an essential property of proliferating mammalian cells. In human T24 bladder cancer cells, several hours of hypoxia leads to reversible DNA replication arrest and re-entry of oxygen induces a burst of replication initiation. This short communication provides strong evidence that PD184352 initiates DNA replication in living hypoxic cells without elevating the oxygen level. PD184352 releases the regular hypoxic replicon arrest, however, at a low intensity compared to the effect of reoxygenation. Moreover, PD184352 shows no effect on normoxically incubated as well as reoxygenated T24 cells.

• Journal of Microbiology
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• 제33권3호
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• pp.191-195
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• 1995

IciA protein has been shown as an inhibitor for the initiation of E. coli chromosomal DNA replication at oriC. IciA protein binds the AT-rich region in oriC and then blocks the initiation of chromosomal DNA replication. Two binding sites for IciA protein were identified in dnaA gene, encoding the initiator for the E. coli chromosomal replication, promoter region by gel-shift assay and DNase I footprinting, One, named as IciA site I, is located upstream of the dnaA promoter 1P. The other, named as IciA site II, is located downstream of the dnaA promoter 2P. The sequence comparison of the regions protected from the DNase I cleavage did not result in a clear consensus sequence for the binding of IciA protein, suggesting that IciA protein may be a member of multimeric complex dsDNA binding proteins. This study provided information about the binding mode of IciA protein. Even though the IciA site II and IciA binding site in oriC seem to be composed of two IciA binding units, one binding unit is likely enough to cause the binding of IciA protein to the IciA site I. The binding of IciA protein to the dna4 promoter implies that IciA protein may involve not only the control of the initiation of chromosomal DNA replication but also the control of the dna4 gene expression.

• 미생물학회지
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• 제31권1호
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• pp.44-47
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• 1993

A replication initiation gene was identified and its nucleotide sequence has been determined from a 3.8 kb, chloramphenicol acethyltransferase conferring R-plasmid pSBK203 of Staphylococcus aures. Location of the replication related region of pSBK 203 was determined by interuption with pUC 119 at XBaI and MspI sites which resulted in inactivation of replication in Bacilius subtilis. Base sequence of this region revealed on open reading frame of 942 base pairs, which encoded a 314 amino acid protein. Base sequence homology with other rep of pT181 family plasmids such as pT181, pC221, pC223, pS194, pU112, and pCW7 was ranged from 78% to 97% and the predicted amino acid sequence homology was from 72% to 95%.

• BMB Reports
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• 제40권5호
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• pp.805-813
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• 2007

Although MCM2 is obviously important for the initiation of eukaryotic DNA replication, its role in $O_2$ dependent regulation of replicon initiation is poorly understood. In this report, I analysed the changes of MCM2 during the transition from hypoxically suppressed replicon initiation to the burst of initiation triggered by reoxygenation in T24 cells. A high level of chromatin bound and nucleosolic MCM2 was found under the hypoxic replicon arrest. In contrast low cytosolic MCM2 was noticed. Recovery of $O_2$ induced phosphorylation and diminution of chromatin bound MCM2, whereas cytosolic MCM2 increased. The level of chromatin bound Cdc7 did not change significantly upon reoxygenation. However, after reoxygenation, significant phosphorylation of Cdc7 and an increase of coimmunoprecipitation with its substrate (MCM2) were observed. This provides a hint that reoxygenation may promote the kinase activity of Cdc7. These changes might be the critical factors in $O_2$ dependent regulation of replicon initiation. Moreover, phosphorylation of Cdc7 by Cdk2 can be observed in vitro, but seems to fail to regulate the level of chromatin bound Cdc7 as well as the changes of MCM2 in response to reoxygenation of hypoxically suppressed cells.

• 한국동물학회지
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• 제37권4호
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• pp.437-477
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• 1994

The DNA replication of human Iyrnphocvtes was studied using Bromodeo3fyuridine incorporation. The characteristic patterns of dvnamlc banding were analysed. Human chromosomal ONA was synthesized in a segmental but highly coordinated fashion. Each chromosome replicates according to its innate pattern of chromosome structure (bandinsl. R-positive bands are demonstrated as the initiation sites of DNA synthesis, and G-bnads initiate replication after it has been completed in the autosomal R-bands. Many researchers demonstrated that developmental or induced methvlation of DNA can inactivate the associated gene loci. Such DNA methylation can be reversed and specific genes reactivated by treatment with 5-azacvtidine. We treated the hvpomethvlating agent 5-azacvtidine and tested for changes of DNA replication pattern. Treatment with 5-azacytidine causes an advance in the time of replication. These observed changes in timing of replication suggest that DNA methvlation may modify regional groups of genes in concert.

• 한국동물학회:학술대회논문집
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• 한국동물학회 2003년도 한국생물과학협회 학술발표대회
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• pp.57-57
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• 2003

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