Publications by authors named "Han Sae Lee"

BRCA1-associated protein-1 (BAP1) is a ubiquitin C-terminal hydrolase domain-containing deubiquitinase with tumor suppressor activity. The gene encoding BAP1 is mutated in various human cancers, with particularly high frequency in kidney and skin cancers, and BAP1 is involved in many cancer-related cellular functions, such as DNA repair and genome stability. Although BAP1 stimulates DNA double-strand break repair, whether it functions in nucleotide excision repair (NER) is unknown.

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Background: Melanins are a heterologous group of biopolymeric pigments synthesized by diverse prokaryotes and eukaryotes and are widely utilized as bioactive materials and functional polymers in the biotechnology industry. Here, we report the high-level melanin production using a new melanogenic Flavobacterium kingsejongi strain and a recombinant Escherichia coli overexpressing F. kingsejongi 4-hydroxyphenylpyruvate dioxygenase (HPPD).

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The INO80 chromatin remodeling complex has roles in many essential cellular processes, including DNA replication. However, the mechanisms that regulate INO80 in these processes remain largely unknown. We previously reported that the stability of Ino80, the catalytic ATPase subunit of INO80, is regulated by the ubiquitin proteasome system and that BRCA1-associated protein-1 (BAP1), a nuclear deubiquitinase with tumor suppressor activity, stabilizes Ino80 via deubiquitination and promotes replication fork progression.

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The recovery from replication stress by restarting stalled forks to continue DNA synthesis is crucial for maintaining genome stability and thereby preventing diseases such as cancer. We previously showed that BRCA1-associated protein 1 (BAP1), a nuclear deubiquitinase with tumor suppressor activity, promotes replication fork progression by stabilizing the INO80 chromatin remodeler via deubiquitination and recruiting it to replication forks during normal DNA synthesis. However, whether BAP1 functions in DNA replication under stress conditions is unknown.

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The INO80 chromatin-remodeling complex performs functions in many chromosomal processes that are crucial for genome stability, such as DNA replication and stalled replication fork recovery. Although these functions suggest that INO80 acts as a tumor suppressor, its specific role in tumorigenesis has remained obscure. Here, we show that a haploinsufficient mutation of Ino80, the catalytic ATPase of the INO80 complex, decreased intestinal adenomatous polyps and increased survival in an Apc mouse model of colon cancer.

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Radiotherapy treats cancer by inducing DNA double-strand breaks (DSB) in tumor cells using ionizing radiation. However, DNA repair in tumor cells often leads to radioresistance and unsuccessful outcome. Inhibition of DNA repair by targeting repair proteins can increase radiosensitivity of tumor cells.

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The INO80 chromatin-remodelling complex has been implicated in DNA replication during stress in yeast. However, its role in normal DNA replication and its underlying mechanisms remain unclear. Here, we show that INO80 binds to replication forks and promotes fork progression in human cells under unperturbed, normal conditions.

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Impairment of dopamine function, which is known to have major effects on behaviors and cognition, is one of the main problems associated with cerebral ischemia. Tadalafil, a long-acting phosphodiesterase type-5 inhibitor, is known to ameliorate neurologic impairment induced by brain injury, but not in dopaminergic regions. We investigated the neuroprotective effects of treatment with tadalafil on cyclic guanosine monophosphate level and dopamine function following cerebral ischemia.

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The formation of γ-H2AX foci after DNA double strand breaks (DSBs) is crucial for the cellular response to this lethal DNA damage. We previously have shown that BRG1, a chromatin remodeling enzyme, facilitates DSB repair by stimulating γ-H2AX formation, and this function of BRG1 requires the binding of BRGI to acetylated histone H3 on γ-H2AX-containing nucleosomes using its bromodomain (BRD), a protein module that specifically recognizes acetyl-Lys moieties. We also have shown that the BRD of BRG1, when ectopically expressed in cells, functions as a dominant negative inhibitor of the BRG1 activity to stimulate γ-H2AX and DSB repair.

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The human INO80 chromatin remodeling complex, comprising the Ino80 ATPase (hIno80) and the associated proteins such as Tip49a, has been implicated in a variety of nuclear processes other than transcription. We previously have found that hIno80 interacts with tubulin and co-localizes with the mitotic spindle and is required for spindle formation. To better understand the role of hIno80 in spindle formation, we further investigated the interaction between hIno80 and microtubule.

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Although recent studies highlight the importance of histone modifications and ATP-dependent chromatin remodelling in DNA double-strand break (DSB) repair, how these mechanisms cooperate has remained largely unexplored. Here, we show that the SWI/SNF chromatin remodelling complex, earlier known to facilitate the phosphorylation of histone H2AX at Ser-139 (S139ph) after DNA damage, binds to gamma-H2AX (the phosphorylated form of H2AX)-containing nucleosomes in S139ph-dependent manner. Unexpectedly, BRG1, the catalytic subunit of SWI/SNF, binds to gamma-H2AX nucleosomes by interacting with acetylated H3, not with S139ph itself, through its bromodomain.

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Objective: To assess testicular rupture, scrotal haematoma, penile fracture and penile injury, comparing the prognoses of surgery and conservative management, as trauma to male external genital organs can cause devastating effects on patients and their partners.

Patients And Methods: We reviewed the medical records of 156 male patients who presented to our emergency centre with trauma to the external genital organs between January 1996 and March 2006.

Results: In all, 74 patients had testicular rupture, 32 penile fracture, 26 a penile injury and 24 a scrotal haematoma (mean age 27.

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Article Synopsis
  • Mammalian SWI/SNF chromatin remodeling complexes are known for their role in transcription but have been found to also be crucial in repairing DNA double-strand breaks (DSBs).
  • Inactivation of these complexes leads to inefficient DSB repair, increased sensitivity to DNA damage, and defects in gamma-H2AX phosphorylation, which is important for DSB repair signaling.
  • The SWI/SNF complexes interact with gamma-H2AX in damaged chromatin, suggesting they assist in the repair process by promoting phosphorylation of H2AX, although they do not alter the expression of key DSB repair genes or DNA damage checkpoints.
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