Publications by authors named "Ukjin Lee"

Prior studies showed that structural loops collapse upon acute cohesin depletion, while regulatory enhancer-promoter (E-P) loops largely persist, consistent with minimal transcriptional changes. However, these studies, conducted in asynchronous cells, could not resolve whether cohesin is required for the establishment of regulatory interactions and transcriptional activation during cell division or cell state transitions. To address this gap, we degraded RAD21, a core cohesin subunit, in naïve mouse embryonic stem cells (ESCs) transitioning from mitosis to G1 either in self-renewal condition or during differentiation toward formative pluripotency.

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Transposable elements (TEs) are abundant in the human genome, and they provide the sources for genetic and functional diversity. The regulation of TEs expression and their functional consequences in physiological conditions and cancer development remain to be fully elucidated. Previous studies suggested TEs are repressed by DNA methylation and chromatin modifications.

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Article Synopsis
  • BRCA2 plays a vital role in maintaining proper telomere function, and its absence causes telomeric damage, leading cells to use alternative mechanisms like break-induced replication (BIR) to manage telomeres.
  • The stabilization of telomeric G-quadruplexes (G4) when BRCA2 is depleted results in the accumulation of TERRA-R-loops, which trigger liquid-liquid phase separation (LLPS) and formation of specific bodies (APBs) associated with ALT.
  • Research suggests that targeting the interactions of telomeric G4 and TERRA-R-loops could be a promising strategy for treating cancers, particularly those with BRCA2 mutations that display ALT characteristics.
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Mammalian embryogenesis commences with two pivotal and binary cell fate decisions that give rise to three essential lineages: the trophectoderm, the epiblast and the primitive endoderm. Although key signaling pathways and transcription factors that control these early embryonic decisions have been identified, the non-coding regulatory elements through which transcriptional regulators enact these fates remain understudied. Here, we characterize, at a genome-wide scale, enhancer activity and 3D connectivity in embryo-derived stem cell lines that represent each of the early developmental fates.

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Mammalian embryogenesis commences with two pivotal and binary cell fate decisions that give rise to three essential lineages, the trophectoderm (TE), the epiblast (EPI) and the primitive endoderm (PrE). Although key signaling pathways and transcription factors that control these early embryonic decisions have been identified, the non-coding regulatory elements via which transcriptional regulators enact these fates remain understudied. To address this gap, we have characterized, at a genome-wide scale, enhancer activity and 3D connectivity in embryo-derived stem cell lines that represent each of the early developmental fates.

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Hippo signaling is known to maintain balance between cell proliferation and apoptosis via tight regulation of factors, such as metabolic cues, cell-cell contact, and mechanical cues. Cells directly recognize glucose, lipids, and other metabolic cues and integrate multiple signaling pathways, including Hippo signaling, to adjust their proliferation and apoptosis depending on nutrient conditions. Therefore, the dysregulation of the Hippo signaling pathway can promote tumor initiation and progression.

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Wnt signaling is mainly transduced by β-catenin via regulation of the β-catenin destruction complex containing Axin, APC, and GSK3β. Transcription factor EB (TFEB) is a well-known master regulator of autophagy and lysosomal biogenesis processes. TFEB's nuclear localization and transcriptional activity are also regulated by various upstream signals.

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Controlled cell growth and proliferation are essential for tissue homeostasis and development. Wnt and Hippo signaling are well known as positive and negative regulators of cell proliferation, respectively. The regulation of Hippo signaling by the Wnt pathway has been shown, but how and which components of Wnt signaling are involved in the activation of Hippo signaling during nutrient starvation are unknown.

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The Hippo pathway plays a pivotal role in tissue homeostasis and tumor suppression. YAP and TAZ are downstream effectors of the Hippo pathway, and their activities are tightly suppressed by phosphorylation-dependent cytoplasmic retention. However, the molecular mechanisms governing YAP/TAZ nuclear localization have not been fully elucidated.

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Phosphatidylinositol 4-phosphate 5-kinase (PIP5K) family members generate phosphatidylinositol 4,5-bisphosphate (PIP2), a critical lipid regulator of diverse physiological processes. The PIP5K-dependent PIP2 generation can also act upstream of the oncogenic phosphatidylinositol 3-kinase (PI3K)/Akt pathway. Many studies have demonstrated various mechanisms of spatiotemporal regulation of PIP5K catalytic activity.

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Pseudomonas fluorescens is an efficient platform for recombinant protein production. P. fluorescens has an ABC transporter secreting endogenous thermostable lipase (TliA) and protease, which can be exploited to transport recombinant proteins across the cell membrane.

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Synopsis of recent research by authors named "Ukjin Lee"

  • - UkJin Lee's recent research primarily focuses on the regulatory mechanisms underlying gene expression and cellular behaviors during embryonic development and cancer progression, emphasizing the roles of transcription factors, non-coding regulatory elements, and metabolic pathways.
  • - Key findings highlight how the disruption of specific proteins, such as BRCA2, affects telomere maintenance and gene expression through novel mechanisms like phase separation and enhancer-promoter interactions, providing insight into cellular responses to damage and fate determination.
  • - The work also sheds light on the interactions between metabolic pathways and signaling cascades, particularly the Hippo pathway, suggesting a complex relationship where nutrient levels influence cellular growth and tumorigenesis, thus advancing understanding of cancer biology.

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