• BMB Reports
• /
• 제43권4호
• /
• pp.284-290
• /
• 2010

Replication of positive-strand RNA virus is mediated by a virus-encoded RNA-dependent RNA polymerase (RdRp). To study the replication of Ectropis obliqua virus (EoV), a newly identified insect virus belonging to the family Iflaviradae, we expressed the RNA polymerase domain in Escherichia coli and purified it on a Ni-chelating HisTrap affinity column. It is demonstrated that EoV RdRp initiated RNA synthesis in a primer and poly (A)-dependent manner in vitro. Furthermore, the effect of primer concentration, temperature, metal ions ($Mg^{2+}$, $Mn^{2+}$, and $K^+$) on enzymatic activity were determined. Our study represented a first step towards understanding the mechanism of EoV replication.

• BMB Reports
• /
• 제28권6호
• /
• pp.538-545
• /
• 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%.

• 생명과학회지
• /
• 제19권3호
• /
• pp.305-310
• /
• 2009

플라스미드 pGKV21에는 229-nt single-strand DNA initiation (ssi) signal이 존재한다. Asymmetric PCR 기법으로 합성된 229-nt ssDNA 단편을 이용하여 실제로 RNA polymerase에 의한 priming ability와 protein interaction을 확인하였다. in vitro primer RNA 합성 실험 결과, 229-nt ssDNA 단편은 filamentous M13 phage의 주형 DNA에서와 비슷한 효율로 시발체 RNA를 합성하였으며, 이 반응은 strand-specific하게 이루어졌다. DNase I footprinting과 gel retardation 실험 결과, RNA polymerase와 SSB 단백질은 229-nt ssDNA 단편에 stable interaction을 하며, 시발체 RNA를 합성하였다. 또한, in vivo 조건 하에서 RNA polymerase의 저해제인 rifampicin을 처리하여 세포내에 ssDNA 중간체가 집적되는 정도를 비교하여 본 결과, 플라스미드 pGKV21은 rifampicin-sensitive RNA polymerase가 상보가닥 합성에 관여 함을 보여 주었다.

• BMB Reports
• /
• 제39권5호
• /
• pp.571-577
• /
• 2006

Dendrolimus punctatus tetravirus (DpTV) has been identified as a new member of the genus Omegatetravirus of the family Tetraviridae that may be related serologically to Nudaurelia capensis virus ($N{\omega}V$). To establish the function of DpTV RNA genome and to better understand the mechanism of viral replication, the putative RNA-dependent RNA polymerase (RdRp) domain has been cloned and expressed in Escherichia coli. The recombinant protein was purified on a Ni-chelating HisTrap affinity column and demonstrated to initiate viral RNA synthesis in a primer-independent manner but not by terminal nucleotidyle transferase activity in the presence of $Mg^{2+}$ and RNA template. Mutation of the GDD to GAA interferes with the residues at the polymerase active site and metal ions, and thus renders the polymerase inactive.

• Journal of Microbiology
• /
• 제45권5호
• /
• pp.418-421
• /
• 2007

The nucleotide at position 791(G791) of E. coli 16S rRNA was previously identified as an invariant residue for ribosomal function. In order to characterize the functional role of G791, base substitutions were introduced at this position, and mutant ribosomes were analyzed with regard to their protein synthesis ability, via the use of a specialized ribosome system. These ribosomal RNA mutations attenuated the ability of ribosomes to conduct protein synthesis by more than 65%. A transition mutation (G to A) exerted a moderate effect on ribosomal function, whereas a transversion mutation (G to C or U) resulted in a loss of protein synthesis ability of more than 90%. The sucrose gradient profiles of ribosomes and primer extension analysis showed that the loss of protein-synthesis ability of mutant ribosomes harboring a base substitution from G to U at position 791 stems partially from its inability to form 70S ribosomes. These findings show the involvement of the nucleotide at position 791 in the association of ribosomal subunits and protein synthesis steps after 70S formation, as well as the possibility of using 16S rRNA mutated at position 791 for the selection of second-site revertants in order to identify ligands that interact with G791 in protein synthesis.

• 한국생물물리학회:학술대회논문집
• /
• 한국생물물리학회 2001년도 학술 발표회 진행표 및 논문초록
• /
• pp.22-22
• /
• 2001

At the eukaryotic replication fork, discontinuous synthesis of lagging strand DNA gives rise to Okazaki fragments carrying ribonucleotides derived from the primer RNA at their 5' ends. Efficient removal of these ribonucleotides is vital for maintaining genome integrity. In this report we show that the endonucleases Dna2 and Fen1 act sequentially to facilitate the complete removal of the primer RNA.(omitted)

• 한국양식학회지
• /
• 제13권1호
• /
• pp.79-85
• /
• 2000

자성 및 웅성스테로이드 호르몬들이 Vg 유전자발현에 영향을 미치는지를 미성숙 무지개송어의 배양간세포 막간을 이용하여 조사하였다. 이미 보고된 송어의 Vg gene의 염기배열을 참고로 Vg cDNA 단편(600 bp)을 증폭시킬 수 있는 primer들을 작성하였다. 이들 primer를 이용하여 증폭된 PCR 산물의 염기배열을 결정하여 송어의 Vg cDNA임을 확인하였고, RT-PCR법을 이용하여 배양간세포 그리고 E$_2$ 및 MT 처리된 송어의 간으로부터 Vg mRNA의 전사량 변화를 조사하였다. 호르몬 처리된 간세포 및 송어의 간에서 추출한 total RNA를 이용하여 RT-PCR법으로 분석한 결과 in vivo, in vitro 실험 모두에서 E$_2$ 또는 MT처리된 간세포 및 송어의 간으로부터 Vg mRNA와 Vg 단백질합성이 유도되었고, 이들의 증가 경향은 처리된 호르몬 농도 및 시간에 의존하고 있음이 밝혀졌다. 또한 progesterone, androsterone 그리고 testosterone 등의 웅성호르몬들도 Vg mRNA의 전사를 유도하고 있다는 것이 시사되었다. 이와 같은 결과로부터E$_2$ 뿐 아니라 웅성스테로이드들도 Vg mRNA의 발현을 유도하고 있음이 송어의 in vivo 또는 in vitro 실험에 의해서 확인되었다.

• 식물병연구
• /
• 제23권2호
• /
• pp.193-201
• /
• 2017

국내의 토마토에서 발생하는 주요 바이러스는 Tomato chlorosis virus (ToCV), Tomato spotted wilt virus (TSWV), Cucumber mosaic virus (CMV), Pepper mottle virus (PepMoV), Tomato mosaic virus (ToMV)이다. 이들 바이러스를 진단하기 위해 프라이머 세트와 반응액을 포함하는 역전사중합반응(RT-PCR)법의 조건을 조사하였다. 공시한 바이러스에 특이적인 염기서열로부터 모두 46개 프라이머 세트를 설계하고, 이를 이용해 주형을 넣지 않은 RT-PCR에서 비특이 반응을 조사하였다. 이들 가운데 16개 조합을 건전한 토마토 RNA에 적용한 결과 프라이머 세트와 RT-PCR 반응액 간의 친화성이 비특이 반응 감소에 영향을 주었다. cDNA 합성과 관련된 인자와 RT-PCR 반응액 사이의 조합을 근거로 ToCV 진단을 위한 두 종류의 반응액을 선발하였다. ToCV 진단 시 수립된 조건을 나머지 바이러스 진단에 적용했을 때, 특이성이 높은 프라이머 세트 C029 (ToCV), C072 (TSWV), C070 (CMV), C048 (PepMoV), C065 (ToMV)를 선발할 수 있었다. 이들 프라이머 세트는 공시한 바이러스를 특이적으로 진단하는 데 유용할 것으로 판단된다.

• 한국작물학회지
• /
• 제38권3호
• /
• pp.275-282
• /
• 1993

본 연구는 한국 옥수수의 $\alpha$-amylase의 유전자 클로닝을 주된 목표로 하여 수행되었다. 이를 위하여 여러 식물체의 $\alpha$-amylase 염기서열로 부터 잘 보존된 부분을 참고로 oligonucleotlde probe 및 PCR primer를 설계, 합성하고, 옥수수의 유묘로부터 전체 RNA를 분리하여 northern blot analysis를 통하여 확인한 다음, 이로부터 첫 번째 가닥 cDNA를 만든 후, 여기서 얻은 RNA : DNA hybrid를 주형으로 한 polymerase chain reaction을 통하여 길이 가 약 500bp되 는 PCR 산물을 얻었다. 이를 클로닝하기 위해 pUC19을 클로닝 백터로 사용하여 재조합 플라스미드인 $\ulcorner$pZM$\alpha$'$\lrcorner$를 만들었다. 합성 probe를 이용, Southern blot analysis한 결과, $\ulcorner$pZM$\alpha$'$\lrcorner$가 옥수수 mRNA로 부터 증폭된 DNA의 일부분을 갖고 있음을 확인하였으며, 그 길이는 PCR 산물과 같은 500bp가량 되는 것으로 나타났다.

• 한국식물병리학회지
• /
• 제10권3호
• /
• pp.228-234
• /
• 1994

Genomic RNA was extracted from Cy strain of odontoglossum ringspot tobamovirus (ORSV-Cy) isolated from infected leaves of tobacco cv. Samsun. Size of the genomic RNA was about 6.6 kb in length. The genomic RNA was fractionated using Sephadex G-50 column chromatography into 2 fractions. They were polyadenylated at their 3'-end using E. coli poly(A) polymerase. Polyadenylated viral RNA was recovered by oligo (dT) primer adapter containing NotI restriction site and Moloney murine leukemia virus SuperScript reverse transcriptase (RNase H-). Second-strand cDNA was synthesized by using E. coli DNA ligase, E. coli DNA polymerase I and E. coli RNase H. Recombinant plasmids containing cDNAs for ORSV-Cy RNA ranged from about 800 bp to 3,000 bp. Among the selected 238 recombinants, pORCY-124 clone was the largest one covering 3'-terminal half of the viral RNA. This clone contained two restriction sites for EcoRI and XbaI and one site for AccI, AvaI, BglII, BstXI, HindIII, PstI, and TthIII 1. respectively. The clone contained partial viral replicase, a full-length movement protein and a complete coat protein genes followed by a 3' untranslated region of 414 nucleotides based on restriction mapping and nucleotide sequencing analyses. Clones pORCY-028, -068, -072, -187 and -224 were overlapped with the pORCY-124. Clones pORCY-014 and -095 covered 5' half upstream from the middle region of the viral RNA, which was estimated based on restriction mapping and partial sequence analysis. Constructed cDNA library covered more than 90% of the viral genome.