• Korean Journal of Plant Tissue Culture
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• v.22 no.5
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• pp.241-260
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• 1995

Transposons, present in the genomes of all living organisms, are genetic element that can change positions, or transpose, within the genome. Most genomes contain several kinds of transposable elements and the molecular details of the mechanisms by which these transposons move have recently been uncovered in many families of transposable elements. Transposition is brought about by an enzyme known as transposaese encoded by the autonomous transposon itself, but, in the unautonomous transposon lacking the gene encoding the transposase, movement occurs only at the presence of the enzyme encoded by the autonomous one. There are two types of transposition events, conservative and replicative transposition. In the former the transposon moves without replication, both strands of the DNA moving together from one place to the other while in the latter the transposition frequently involves DNA replication, so one copy of transposon remains at its original site as another copy insole to a new site. The insertion of transposon into a gene can prevent it expression whereas excision from the gene may restore the ability of the gene to be expressed. There are marked similarities between transposons and certain viruses having single stranded Plus (+) RNA genomes. Retrotransposons, which differ from the ordinary transposons in that they transpose via an RNA-intermediate, behave much like retroviruses and have a structure of integrated retrovial DNA when they are inserted to a new target site. An insertional mutagenesis called transposon-tagging is now being used in a number of plant species to isolate genes involved in developmental and metabolic processes which have been proven difficult to approach by the traditional methods. Attempts to device a transposon-tagging system based on the maize Ac for use in heterologous species have been made by many research workers.

• Proceedings of the Zoological Society Korea Conference
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• 1999.04a
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• pp.33-33
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• 1999

No Abstract, See Full Text

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2004.10a
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• pp.41-42
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• 2004

• Journal of Life Science
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• v.11 no.1
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• pp.30-33
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• 2001

To identify novel components involved in the salt stress signaling pathway of yeast cells, we used mTn3-mediated transposon tagging library and screened mutants displaying enhanced tolerance to NaCl. Southern blot analysis indicated that more than 80% of the sre (salt resistant) mutants possessed only one insertion of the tagged transposon, suggesting that the NaCl resistant phenotype was mediated by a single gene in the majority of the mutants. To define the role of SRE genes in the salt stress signaling pathway, we introduced NaCl stress-inducible ENA1::LacZ construct into the sre mutants and examined the expression of ${\beta}$-galactosidase activity. Interestingly, we could detect high level of ${\beta}$-galactosidase activity without any NaCl treatment in the sre-3, 4, 6 and 7 mutants. These results indicate that SRE-3, 4, and 7 gene are components of salt stress signaling pathway of yeast cells.

• Journal of Plant Biotechnology
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• v.38 no.1
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• pp.94-104
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• 2011

Salt stress is a major environmental factor influencing plant growth and development. To identify salt tolerance determinants, we systematically screened salt sensitive rice mutants by use of the Activator/Dissociation (Ac/Ds) transposon tagging system. In this study, we focused on the salt sensitive mutant line, designated SSM-1. A gene encoding a NAC transcription factor homologue was disrupted by the insertion of a Ds transposon into SSM-1 line. The OsNAC075 gene (EU541472) has 7 exons and encodes a protein (486-aa) containing the NAC domain in its N-terminal region. Sequence comparison showed that the OsNAC075 protein had a strikingly conserved region at the N-terminus, which is considered as the characteristic of the NAC protein family. OsNAC075 protein was orthologous to Arabidopsis thaliana ANAC075. Phylogenetic analysis confirmed OsNAC075 belonged to the OsNAC3 subfamily, which plays an important role in response to stress stimuli. RT-PCR analysis showed that the expression of OsNAC075 gene was rapidly and strongly induced by stresses such as NaCl, ABA and low temperature ($4^{\circ}C$). Our data suggest that OsNAC075 holds promising utility in improving salt tolerance in rice.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2005.11a
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• pp.95-105
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• 2005

Transposon-mediated insertional mutagenesis provides one of the most powerful tools for functional studies of genes in higher plants. This project has been performed to develop a large population of insertional mutations, and to construct databases of molecular information on Ds insertion sites in rice. Ultimate goals are to supply genetic materials and information to analyze gene function and to identify and utilize agronomically important genes for breeding purpose. Two strategies have been employed to generate the large scale of transposon population in a Japonica type rice, Dongjin Byeo; 1) genetic crosses between Ac and Ds lines and 2) plant regeneration from seeds carrying Ac and Ds. Our study showed that over 70% of regenerated plants generally carried independent Ds elements and high activity of transposition was detected only during regeneration period. Ds-flanking DNA amplified from leaf tissues of F2 and T1 (or T2) plants have been amplified via TAIL-PCR and directly sequenced. So far, over 65,000 Ds lines have been generated and over 9,500 Ds loci have been mapped on chromosomes by sequence analysis. Database of molecular information on Ds insertion sites has been constructed, and has been opened to the public and will be updated soon at http://www.niab.go.kr. Detailed functional analysis of more than 30 rice mutants has been performed. Several Ds-tagged rice genes that have been selected for functional analysis will be briefly introduced. We expect that a great deal of information and genetic resources of Ds lines would be obtained during the course of this project, which will be shared with domestic and international rice researchers. In addition to the Japonica rice, we have established the tagging system in an rice line of indica genetic background, MGRI079. MGRI079 (Indica/Japonica) was transformed with Agrobacteria carrying Ac and Ds T-DNA vectors. Among transgenic lines, we successfully identified single-copy Ds and Ac lines in MGR1079. These lines were served as ‘starter lines’ to mutagenize Indica genetic background. To achieve rapid, large scale generation of Ds transposant lines, MGR1079 transformants carrying homozygous Ac were crossed with ones with homozygous Ds, and $F_2$seeds were used for plant regeneration. In this year, over 2,000 regeneration plants were grown in the field. We are able to evaluate the tagging efficiency in the Indica genetic background in the fall.

• Korean Journal of Plant Tissue Culture
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• v.21 no.6
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• pp.319-326
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• 1994

For the gene tagging of Armoracia rusticana, maize controlling element Ac and Ds were introduced into A.rusticana via Agrobacterium-mediated transformation method. We established an efficient in via regeneration and transformation system for gene transfer in A. rusticana. The optimum in via regeneration condition has been obtained from leaf, petiole and root organs on modified MS medium supplemented with NAA 0.1 mg/L plus BA 1.0 mg/L for direct shooting and with free growth regulators for root induction for transformation, the leaf, petiole and root explants of A. rusticana were concultivated with Agrobacterium tumefaciens, LBA4404 which carries a binary vector pEND4K containing maize controlling element Ac or Ds, respectively: Selections were performed in the shoot induction medium supplemented with 100 mg/L kanamycin, and 500 mg/L carbenicillin transformation frequency showed about 8 to 10% in case of leaf disks. PCR md Southern blot analyses showed that the Ac and the Ds elements were integrated into the chromosome of donor plants.

• Proceedings of the Botanical Society of Korea Conference
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• 1987.07a
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• pp.323-347
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• 1987

The R locus of maize in one of several genes that regulate the anthocyanin pigments throughout the body of the plant and seed. The R gene product may regulate pigment deposition by controlling the expression of the flavonoid biosynthetic gene pathway in a tissue-specific manner. To understand the basis for tissue specific regulation and allelic variation at R, the molecular study has been done by cloning a portion of the R complex by transposon tagging with Ac. R specific probe were cloned from the R-nj mutant induced by Ac insertion mutagenesis. From southern analysis of R-r complex using the R-nj probe, the structure of R-r was proposed that R-r containes the three elements, (P)(Q)(S). These elements may organize as the inversion triplication model which (S) sequence was inverted in relation to (P) and (Q). The R-sc derivated from R-mb or R-nj was cloned with R-nj probe, and molecular genetical data showed that R-sc containes tissue specific and tissue nonspecific area, and the sequencing of R-sc are progressed now.

• Journal of Microbiology and Biotechnology
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• v.15 no.6
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• pp.1337-1345
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• 2005

Vibrio vulnificus is the causative agent of foodborne diseases such as gastroenteritis and life-threatening septicemia. Microbial pathogenicity is a complex phenomenon in which expression of numerous virulence factors is frequently controlled by a common regulatory system. In the present study, a mutant exhibiting decreased cytotoxic activity toward intestinal epithelial cells was screened from a library of V. vulnificus mutants constructed by a random transposon mutagenesis. By a transposon-tagging method, an open reading frame, fexA, a homologue of Escherichia coli areA, was identified and cloned. The nucleotide and deduced amino acid sequences of the fexA were analyzed, and the amino acid sequence of FexA from V. vulnificus was $84\%\;to\;97\%$ similar to those of AreA, an aerobic respiration control global regulator, from other Enterobacteriaceae. Functions of the FexA were assessed by the construction of an isogenic mutant, whose fexA gene was inactivated by allelic exchanges, and by evaluating its phenotype changes in vitro and in mice. The disruption of fexA resulted in a significant alteration in growth rate under aerobic as well as anaerobic conditions. When compared to the wild-type, the fexA mutant exhibited a substantial decrease in motility and cytotoxicity toward intestinal epithelial cell lines in vitro. Furthermore, the intraperitoneal $LD_{50}$ of the fexA mutant was approximately $10^{1}-10^{2}$ times higher than that of parental wild-type. Therefore, it appears that FexA is a novel global regulator controlling numerous genes and contributing to the pathogenesis as well as growth of V. vulnificus.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.3
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• pp.259-268
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• 2006

Miniature inverted transposable elements (MITEs) are abundant genomic components in plant including rice. MITE-transposon display (MITE-TD) is an Amplified Fragment Length Polymorphism (AFLP)-related technique based on MITE sequence. In this study, we used the MITE-AFLP for the analysis of diversity and relation-ship of the 114 japonica accessions. Of the several MITEs, the mPing family was applied to detect polymorphisms based on PCR amplification. The BfaI adaptor primer and the specific primer derived from mPing terminal inverted repeat (TIR) region were used to PCR amplification of 114 accessions. Nine primer pairs produced a total of 160 polymorphic bands. PIC values of the polymorphic bands generated by nine primer pairs ranged from 0.269 (BfaI + ACT) to 0.426 (BfaI + T). Each accession revealed a distinct fingerprint with two primer combinations, BfaI + G and BfaI + C. Cluster analysis using marker-based genetic similarity classified 114 accessions into five groups. MITE-AFLP markers were genetically mapped using a population of 80 BILs (BC1F7) derived from a cross between the rice accessions, Milyang 23 and Hapcheonaengmi 3. Eight of the markers produced with the primer pair BfaI + 0 were mapped on chromosomes 1, 2, 4, 5, 7, and 9. Considering that one MITE-AFLP marker on chromosome 7 was tightly linked to the Rc gene, the MITE-AFLP markers will be useful for gene tagging and molecular cloning.