https://scholar.dgist.ac.kr/handle/20.500.11750/13652 2026-08-03T08:52:23Z 2026-08-03T08:52:23Z Park, Celine Jung, Jaehun Hong, Yuri Yoo, Haeun Yang, Keunsang Shin, Jaehyeon Kim, Minsik Lim, Chan Jeong, Ayoung Hong, Seokyun Baek, Jun Young Rah, Sang-Hyun Lee-Eom, Chaelin Seo, Minseok Kim, Yoori Jeon, Jae-Hyung Lee, Jong-Bong Hwang, Dong Soo Shon, Min Ju https://scholar.dgist.ac.kr/handle/20.500.11750/60469 2026-07-22T18:01:22Z 2025-12-31T15:00:00Z

Title: Tau condensation on DNA mediates microtubule attachment suggesting a mitotic role for centromere-localized tau Author(s): Park, Celine; Jung, Jaehun; Hong, Yuri; Yoo, Haeun; Yang, Keunsang; Shin, Jaehyeon; Kim, Minsik; Lim, Chan; Jeong, Ayoung; Hong, Seokyun; Baek, Jun Young; Rah, Sang-Hyun; Lee-Eom, Chaelin; Seo, Minseok; Kim, Yoori; Jeon, Jae-Hyung; Lee, Jong-Bong; Hwang, Dong Soo; Shon, Min Ju Abstract: Tau protein, traditionally recognized for stabilizing microtubules and forming pathological aggregates, has recently been observed to form condensates in various contexts. While its condensation with RNA has been well studied, the interaction between tau and DNA, along with its biological significance, remains less explored. Here, using single-molecule experiments, we find that tau binds stably to naked DNA at nanomolar concentrations, leading to the local co-condensation of tau and DNA. These tau condensates on DNA can also interface with microtubules, leveraging tau's known role in promoting microtubule growth and organization. The dynamic nature of these condensates facilitates the remodeling of the DNA-microtubule assembly. Interestingly, phosphorylated tau and nucleosomal DNA exhibit distinct capacities to form condensates and recruit microtubules. Furthermore, imaging of mitotic cells with endogenous or exogenous tau reveals its localization to centromeres, engaging mitotic spindles, whereas expression of phosphomimetic tau mutants (T231D/S235D and S262D) causes defects in chromosome alignment. Building on these observations, we speculate that tau may play a role in mitosis, where tau clusters facilitate the early registration of mitotic spindles to chromosomes before kinetochore-mediated attachment. We also discuss the implications of this model in conditions where abnormal cell cycle re-entry and tau activity may disrupt cell division.

2025-12-31T15:00:00Z Kim, Seongmin Kim, Dahoon Kim, Yoori https://scholar.dgist.ac.kr/handle/20.500.11750/59937 2026-02-08T16:10:23Z 2025-08-31T15:00:00Z

Title: Metal-stabilized G-quadruplexes: biological insights and sensing applications Author(s): Kim, Seongmin; Kim, Dahoon; Kim, Yoori Abstract: Repeat sequences account for approximately 45% of the human genome, and can produce noncanonical DNA secondary structures that include G-quadruplexes (G4s). Among these, G4s are unique, in that their formation and stability are largely influenced by metal cations, such as Na+, K+, Ca2+, and Mg2+. These cations stabilize G4 structures, while also influencing their folding and biological activities. Interactions between G4s and metal ions affect key cellular processes that include transcription, replication, and genome stability. This review highlights the structural diversity and functional roles of G4s, and further explores how their ion-dependent properties have been harnessed for applications in biosensing and therapeutic development. Future research directions to advance G4-targeted technologies for both diagnostic and clinical use are also discussed.

2025-08-31T15:00:00Z Seo, Minseok Kim, Bokyung Shin, Hyogyung Kim, Jinwoo Lee, Jong-bong Ko, Young-ho Kim, Jin Hae Kim, Yoori https://scholar.dgist.ac.kr/handle/20.500.11750/59922 2026-02-08T16:10:22Z 2025-09-30T15:00:00Z

Title: Structural and dynamic basis of Ssp4-mediated DNA protection in foodborne bacterial spores Author(s): Seo, Minseok; Kim, Bokyung; Shin, Hyogyung; Kim, Jinwoo; Lee, Jong-bong; Ko, Young-ho; Kim, Jin Hae; Kim, Yoori Abstract: Clostridium perfringens forms metabolically dormant endospores that withstand extreme environmental conditions. Small acid-soluble proteins (SASPs) are ubiquitous DNA-binding proteins in endospores that promote resistance. While their protective role has been previously characterized, we aimed to provide further biophysical insight into the nature of these interactions, focusing on variant-specific structural dynamics through novel single-molecule and NMR approaches. Here, we characterize the DNA-binding properties and structural features of two Ssp4 variants using single-molecule fluorescence imaging and NMR spectroscopy along with electrophoretic mobility shift assays (EMSA). Both Ssp4 variants bind DNA cooperatively, but single-molecule analysis revealed preferential binding to GC-rich regions and significantly increased residence time in the presence of dipicolinic acid (DPA). NMR analysis reveals that an aspartic acid residue at position 36 (D36) stabilizes the Ssp4 structure, and its removal induces local structural perturbations without altering DNA affinity. Our findings provide molecular insights into how Ssp4 variants protect DNA in substantially dehydrated endospores and promote spore survival. © 2025 Elsevier B.V., All rights reserved.

2025-09-30T15:00:00Z Zhang, Hongshan Shi, Zhubing Banigan, Edward J. Kim, Yoori Yu, Hongtao Bai, Xiao-chen Finkelstein, Ilya J. https://scholar.dgist.ac.kr/handle/20.500.11750/46372 2025-07-25T03:25:15Z 2023-07-31T15:00:00Z

Title: CTCF and R-loops are boundaries of cohesin-mediated DNA looping Author(s): Zhang, Hongshan; Shi, Zhubing; Banigan, Edward J.; Kim, Yoori; Yu, Hongtao; Bai, Xiao-chen; Finkelstein, Ilya J. Abstract: Cohesin and CCCTC-binding factor (CTCF) are key regulatory proteins of three-dimensional (3D) genome organization. Cohesin extrudes DNA loops that are anchored by CTCF in a polar orientation. Here, we present direct evidence that CTCF binding polarity controls cohesin-mediated DNA looping. Using single-molecule imaging, we demonstrate that a critical N-terminal motif of CTCF blocks cohesin translocation and DNA looping. The cryo-EM structure of the cohesin-CTCF complex reveals that this CTCF motif ahead of zinc fingers can only reach its binding site on the STAG1 cohesin subunit when the N terminus of CTCF faces cohesin. Remarkably, a C-terminally oriented CTCF accelerates DNA compaction by cohesin. DNA-bound Cas9 and Cas12a ribonucleoproteins are also polar cohesin barriers, indicating that stalling may be intrinsic to cohesin itself. Finally, we show that RNA-DNA hybrids (R-loops) block cohesin-mediated DNA compaction in vitro and are enriched with cohesin subunits in vivo, likely forming TAD boundaries. © 2023 Elsevier Inc.

2023-07-31T15:00:00Z