Seung-Hoon Jeon

We have produced 22 090 primary transgenic rice plants that carry a T-DNA insertion, which has resulted in 18 358 fertile lines. Genomic DNA gel-blot and PCR analyses have shown that approximately 65% of the population contains more than one copy of the inserted T-DNA. Hygromycin resistance tests revealed that transgenic plants contain an average of 1.4 loci of T-DNA inserts. Therefore, it can be estimated that approximately 25 700 taggings have been generated. The binary vector used in the inse

The molecular mechanisms of the DNA mismatch repair (MMR) system have been uncovered over the last decade, especially in prokaryotes. The results obtained for prokaryotic MMR proteins have provided a framework for the study of the MMR system in eukaryotic organisms, such as yeast, mouse and human, because the functions of MMR proteins have been conserved during evolution from bacteria to humans. However, mutations in eukaryotic MMR genes result in pleiotropic phenotypes in addition to MMR defect

EIN2 is a central signal transducer in the ethylene-signaling pathway, and a unique membrane-anchored protein. By screening a cDNA library, we have isolated a cDNA clone (OsEIN2) that encodes the rice EIN2 homolog. The full-length ORF clone was obtained by reverse transcriptase-polymerase chain reaction. OsEIN2 shares significant amino acid sequence similarity with Arabidopsis EIN2 (57% similarity and 42% identity). Both the numbers and positions of introns and exons in the OsEIN2 and AtEIN2 cod

A novel light-driven chloride-pumping rhodopsin (ClR) containing an 'NTQ motif' in its putative ion conduction pathway has been discovered and functionally characterized in a genomic analysis study of a marine bacterium. Here we report the crystal structure of ClR from the flavobacterium Nonlabens marinus S1-08(T) determined under two conditions at 2.0 and 1.56 Å resolutions. The structures reveal two chloride-binding sites, one around the protonated Schiff base and the other on a cytoplasmic lo

Abstract The bacterial effector proteins SseK and NleB glycosylate host proteins on arginine residues, leading to reduced NF-κB-dependent responses to infection. Salmonella SseK1 and SseK2 are E. coli NleB1 orthologs that behave as NleB1-like GTs, although they differ in protein substrate specificity. Here we report that these enzymes are retaining glycosyltransferases composed of a helix-loop-helix (HLH) domain, a lid domain, and a catalytic domain. A conserved HEN motif (His-Glu-Asn) in the ac

Telomeres are protein-DNA elements that are located at the ends of linear eukaryotic chromosomes. In concert with various telomere-binding proteins, they play an essential role in genome stability. We determined the structure of the DNA-binding domain of NgTRF1, a double-stranded telomere-binding protein of tobacco, using multidimensional NMR spectroscopy and X-ray crystallography. The DNA-binding domain of NgTRF1 contained the Myb-like domain and C-terminal Myb-extension that is characteristic

The anion channel SLAC1 functions as a crucial effector in the ABA signaling, leading to stomata closure. SLAC1 is activated by phosphorylation in its intracellular domains. Both a binding-activation model and an inhibition-release model for activation have been proposed based on only the closed structures of SLAC1, rendering the structure-based activation mechanism controversial. Here we report cryo-EM structures of Arabidopsis SLAC1 WT and its phosphomimetic mutants in open and closed states.

The GroEL/GroES chaperonin system assists the folding of many proteins, through conformational transitions driven by ATP hydrolysis. Although structural information about bullet-shaped GroEL:ES₁ complexes has been extensively reported, the substrate interactions of another functional complex, the football-shaped GroEL:ES₂, remain elusive. Here, we report single-particle cryo-EM structures of reconstituted wild-type GroEL:ES₂ complexes with a chemically denatured

Opening of the DNA binding cleft of cellular RNA polymerase (RNAP) is necessary for transcription initiation but the underlying molecular mechanism is not known. Here, we report on the cryo-electron microscopy structures of the RNAP, RNAP-TFEα binary, and RNAP-TFEα-promoter DNA ternary complexes from archaea, Thermococcus kodakarensis (Tko). The structures reveal that TFEα bridges the RNAP clamp and stalk domains to open the DNA binding cleft. Positioning of promoter DNA into the cleft closes it

Abstract The emergence of fatal viruses that pose continuous threats to global health has fueled the intense effort to develop direct, accurate, and high‐throughput virus detection platforms. Current diagnostic methods, including qPCR and rapid antigen tests, indicate how much of the virus is present, whether small fragments or whole viruses. However, these methods do not indicate the probability of the virus to be active, capable of interacting with host cells and initiating the infection cycle

Molecular-profiling-based cancer diagnosis has significant implications for predicting disease prognosis and selecting targeted therapeutic interventions. The analysis of cancer-derived extracellular vesicles (EVs) provides a noninvasive and sequential method to assess the molecular landscape of cancer. Here, we developed an all-in-one fusogenic nanoreactor (FNR) encapsulating DNA-fueled molecular machines (DMMs) for the rapid and direct detection of EV-associated microRNAs (EV miRNAs) in a sing

BACKGROUND: Middle East respiratory syndrome coronavirus (MERS-CoV) causes severe respiratory disease in humans, with a case fatality rate of approximately 35%, thus posing a considerable threat to public health. The lack of approved vaccines or antivirals currently constitutes a barrier in controlling disease outbreaks and spread. METHODS: In this study, using a mammalian expression system, which is advantageous for maintaining correct protein glycosylation patterns, we constructed chimeric MER

Japanese encephalitis virus (JEV), a flavivirus transmitted by mosquitoes, has caused epidemics and severe neurological diseases in Asian countries. In this study, we developed a cDNA infectious clone, pBAC JYJEV3, of the JEV genotype 3 strain (EF571853.1) using a bacterial artificial chromosome (BAC) vector. The constructed infectious clone was transfected into Vero cells, where it exhibited infectivity and induced cytopathic effects akin to those of the parent virus. Confocal microscopy confir