• Genomics & Informatics
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• 제6권2호
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• pp.84-86
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• 2008

The Tetrahymena group I intron has been shown to employ a trans-splicing reaction and has been modified to specifically target and replace human telomerase reverse transcriptase (hTERT) RNA with a suicide gene transcript, resulting in the induction of selective cytotoxicity in cancer cells that express the target RNA, in animal models as well as in cell cultures. In this study, we evaluated the target RNA specificity of trans-splicing phenomena by the group I intron in mice that were intraperitoneally inoculated with hTERT-expressing human cancer cells to validate the anti-cancer therapeutic applicability of the group I intron. To this end, an adenoviral vector that encoded for the hTERT-targeting group I intron was constructed and systemically injected into the animal. 5'-end RACE-PCR and sequencing analyses of the trans-spliced cDNA clones revealed that all of the analyzed products in the tumor tissue of the virus-infected mice resulted from reactions that were generated only with the targeted hTERT RNA. This study implies the in vivo target specificity of the trans-splicing group I intron and hence suggests that RNA replacement via a trans-splicing reaction by the group I intron is a potent anti-cancer genetic approach.

• BMB Reports
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• 제28권1호
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• pp.57-61
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• 1995

The expression of a recombinant human lactoferrin is reported in mouse HC11 mammary epithelial cells. Expression of human lactoferrin (hLF) was achieved by placing its cDNA under the control of the bovine ${\beta}$-casein gene. To improve the hLF expression level in a cell culture system, two artificial introns were also introduced to construct expression vectors. One intron was a hybrid-splice signal consisting of bovine ${\beta}$-casein intron 1 and rabbit ${\beta}$-globin intron II. The other intron was a DNA fragment spanning intron 8 of the bovine ${\beta}$-casein gene. The hybrid intron moderately elevated hLF expression, whereas intron 8 alone did not express any detectable amount of hLF as judged by Northem and Western blot analyses. When the two introns were used together they contributed to a synergistic elevation of hLF expression. These data indicate that artificial introns on both sides of the hLF cDNA were necessary to increase expression of cDNA.

• 대한예방의학회:학술대회논문집
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• 대한예방의학회 1999년도 제51차 추계 학술대회 연제집
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• pp.1-15
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• 1999

In a case-control study to evaluate the factors involved in the development of hepatocellular carcinoma, polymorphisms of the p53 gene were compared in 68 cases mostly infected with hepatitis C virus (HCV) and 68 controls matched for sex and age: DNA from peripheral blood leukocytes was analyzed by the polymerase chain reaction-single strand conformation polymorphism method and direct sequencing. Polymorphisms analyzed were those in exon 4 (CCC vs. CGC, Pro vs. Arg at codon 72, Al allele vs. A2 allele), intron 2 (C vs. G at nucleotide 38, Al vs. A2), intron 3 (C vs. A at nucleotide 65, Al vs. A2; absence and presence of 16 base pair repeat at nucleotides 24 to 39, Al vs. A2), intron 6 (A vs. G at nucleotide 62, Al vs. A2) and intron 7 (C and T vs. T and G at nucleotides 72 and 92, Al vs. A2). A significantly higher frequency of the allele for CCC (Pro, Al) at codon 72 of exon 4 was found in cases (39%) than in controls (26%) (p<0.05). Highly significant linkage of the polymorphisms in exon 4, intron 2, intron 3 and intron 7, and between the intron 3-16 bp duplication and polymorphism in intron 6 also was found. Matched Fair analysis showed significantly higher frequencies of certain haplotypes (1-1-1-1-2-2 or 1-1-2-1-2-1 for exon 4, intron 2, intron 3, the intron 3-16 bp duplication, intron 6 and intron 7) in cases than in controls (p=0.014, OR=2.27, 95% CI= 1.08-5.12). No preference of specific p53 polymorphisms for specific HCV genotype was detected. These findings suggest that in hepatocarcinogenesis mainly due to HCV infection, genetic factors may be involved and that genetic markers can serve as predictors of a high-risk group for hepatocarcinogenesis.

• 미생물학회지
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• 제35권3호
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• pp.211-217
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• 1999

표적 RNA 의 구조가 Tetrahymena thermophila 의 group I intron 에 의한 trans-splicing 반응에 미치는 영향을 분석하기 위해 강력한 stem-loop 형태의 안정된 구조를 갖고 있는 표적 RNA mapping 분석 방법을 이용한 결과 in vitro 뿐만 아니라 in vivo 에서도 stem 부위의 염기들에 반해 loop 부위의 염기들이 ribozyme 에 의해 잘 인지되었으며 이러한 결과는 그러한 부위들을 인지할 수 있는 ribozyme 들에 의한 trans-cleavage 그리고 trans-splicing 반응을 수행함으로써 검증하였다. 또한 이러한 trans-splicing 반응은 정확하게 일어남을 반응 산물의 염기서열 결정을 통해 확인하였다. 따라서 표적 RNA 의 구조가 in vitro 및 in vivo 에서의 ribozyme 활성에 매우 중요한 요인임을 확인하였다.

• ALGAE
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• 제18권3호
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• pp.183-190
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• 2003

Except for a group I intron in trnL-uaa occuring in eubacteria and plastids, group I introns are rarely documented in plastid genomes. Here, we report that a green alga, Caulerpa sertularioides, contains three group IA3 introns in the 16S gene (cpSSU), CS-cpSSU.i1, CS-cpSSU.i2 and CS-cpSSU.i3. Each intron has an open reading frame with LAGLIDADG motifs. CS-cpSSU.i1orf and CS-cpSSU.i3orf occur at Loop 6 in the intron secondary structure and CScpSSU. i2orf at Loop 8. CS-cpSSU.i1orf and CS-cpSSU.i2orf contain both LAGLI-DADG motifs but CS-cpSSU.i3orf has only one. CS-cpSSU.i1 and CS-cpSSU.i2 share the insetion sites and the ORFs at Loop 6 and 8 with CpSSU·1 and CpSSU·2 introns of Chlamydomonas pallidostigmatica (Chlorophyceae). In contrast, CS-cpSSU.i3, containing 28 copies of GAAATAT at Loop 6, is a novel intron found only in Caulerpa sertularioides. Possible scenarios of the evolution of the three introns and their possible use in systematic research are discussed.

• 미생물학회지
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• 제35권4호
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• pp.253-257
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• 1999

Cadaverine, putrescine, spermidine과 spermine이 spectinomycin에 의한 T4 파지 thymidylate synthase 유전자(td) intron의 splicing 억제에 미치는 영향을 조사하였다. Polyamine이 존재하지 않는 상태에서 7mM spectinomycin은 splicing rate를 약 40% 감소시켰다. 사용한 농도 범위(0.1~5mM)에서 cadaverine은 splicing rate를 감소시켰으나, putrescine은 0.5mM 농도에서 약 13% 정도의 splicing rate를 증가시켰다. Spermidine은 0.5mM 농도에서 약 11% 정도의 splicing rate를 증가시켰으며, sperimine은 0.01mM 농도에서 약 16% 정도의 splicing rate을 증가시켰다. 시험한 polyamine 중에서 특히 sperimine은 가장 낮은 농도에서 spectinomycin에 의한 억제반응을 극복하는 최고의 활성효과를 나타냈다. 이와 같은 억제 회복 효과는 polyamine에 의한 td intron 리보자임의 구조적 안정성에 기인하는 것으로 추정된다.

• 한국독성학회:학술대회논문집
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• 한국독성학회 2003년도 추계학술대회
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• pp.87-88
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• 2003

PegIntron is the pegylated form of human recombinant interferon alfa-2b (IFN${\alpha}$2b). IFN ${\alpha}$2b, known as Intron A, has been in approved clinical use since the 1980's for various cancer indications, and for the treatment of Hepatitis C. In the mid 1990's, several clinical investigators reported that combination therapy with ribavirin and Intron A dramatically increased the therapeutic efficacy for treatment of Hepatitis C.(omitted)

• Journal of Microbiology and Biotechnology
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• 제18권1호
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• pp.23-27
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• 2008

Self-splicing group I introns in tRNA anticodon loops have been found in diverse groups of bacteria. In this work, we identified $tRNA^{fMet}$ group I introns in six strains of marine Synechococcus elongatus. Introns with sizes around 280 bp were consistently obtained in all the strains tested. In a phylogenetic analysis using the nucleotide sequence determined in this study with other cyanobacterial $tRNA^{fMet}$ and $tRNA^{Leu}$ intron sequences, the Synechococcus sequence was grouped together with the sequences from other unicellular cyanobacterial strains. Interestingly, the phylogenetic tree inferred from the intronic sequences clearly separates the different tRNA introns, suggesting that each family has its own evolutionary history.

• Animal cells and systems
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• 제4권2호
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• pp.141-144
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• 2000

Effects of deamido-$\textrm{NAD}^{+}$on self-splicing of primary transcripts of the phage T4 thymidylate synthase gene (td) was investigated. The self-splicing was not affected by deamido-$\textrm{NAD}^{+}$- at concentrations up to 2 mM. However, it began to decrease at 5 mM and the formation of splicing products such as the linear intron, intron-exon 2 and exon 1-exon 2, was slightly reduced. At 20 mM the self-splicing activity was almost completely abolished. This analog of the coenzyme $\textrm{NAD}^{+}$- inhibits the self-splicing of td intron RNA although it does not possess a guanidine group in its structure. The analysis of inhibitory concentrations and structural examination suggests that the key structural features of deamido-$\textrm{NAD}^{+}$ responsible for the inhibition of splicing may be the ADP-ribose moiety.

• Journal of Microbiology
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• 제37권4호
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• pp.243-247
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• 1999

Effects of divalent cations on self-splicing inhibition by the antibiotic spectinomycin of the phage T4 thymidylate synthase intron (td) have been investigated. $Ca^{2+}$ ion at 1mM concentration suppressed splicing inhibition of spectinomycin by 10% and 50 ${\mu}M\;Co^{2+}$ ion also suppressed splicing inhibition of specinomycin by 10%. $Mg^{2+}$ ion at 6 mM concentration decreased splicing inhibition of spectinomycin by 42% while $Mn^{2+}$ ion decreased the splicing inhibition by 10%. $Zn^{2+}$ ion at 10 uM concentration lowered the splicing inhibition by spectinomycin of 15%. Of all divalent cations tested, $Mg^{2+}$ ion was the most effective in suppressing splicing inhibition by specinomycin whereas $Ca^{2+}$ ion was the least effective. The results suggest that spectinomycin may interact with specific and functional $Mg^{2+}$-binding sites within intron RNA that lead to a displacement of $Mg^{2+}$ essential for catalytic activity.