KyungHwan Kim

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The phosphorylation of histone variant H2AX at DNA double-strand breaks is believed to be critical for recognition and repair of DNA damage. However, little is known about the molecular mechanism regulating the exchange of variant H2AX with conventional H2A in the context of the nucleosome. Here, we isolate the H2AX-associated factors, which include FACT(More)
Linker histone H1 has been generally viewed as a global repressor of transcription by preventing the access of transcription factors to sites in chromatin. However, recent studies suggest that H1 can interact with other regulatory factors for its action as a negative modulator of specific genes. To investigate these aspects, we established a human cell line(More)
Many co-regulator proteins are recruited by DNA-bound transcription factors to remodel chromatin and activate transcription. However, mechanisms for coordinating actions of multiple co-regulator proteins are poorly understood. We demonstrate that multiple protein-protein interactions by the protein acetyltransferase TIP60 are required for estrogen-induced(More)
This paper presents a novel fabrication process for a tapered hollow metallic microneedle array using backside exposure of SU-8, and analytic solutions of critical buckling of a tapered hollow microneedle. An SU-8 mesa was formed on a Pyrex glass substrate and another SU-8 layer, which was spun on top of the SU-8 mesa, was exposed through the backside of(More)
HIV-1 Vpr-binding protein (VprBP) has been implicated in the regulation of both DNA replication and cell cycle progression, but its precise role remains unclear. Here we report that VprBP regulates the p53-induced transcription and apoptotic pathway. VprBP is recruited to p53-responsive promoters and suppresses p53 transactivation in the absence of stress(More)
Histone modifications play important roles in the regulation of gene expression and chromatin organization. VprBP has been implicated in transcriptionally silent chromatin formation and cell-cycle regulation, but the molecular basis underlying such effects remains unclear. Here we report that VprBP possesses an intrinsic protein kinase activity and is(More)
The tumor suppressor p53 plays a critical role in mediating cellular response to a wide range of environmental stresses. p53 regulates these processes mainly by acting as a short-lived DNA binding protein that stimulates transcription from numerous genes involved in cell cycle arrest, programmed cell death, and other processes. To investigate the importance(More)
The incorporation of histone variants into nucleosomes is one of the main strategies that the cell uses to regulate the structure and function of chromatin. Histone H2A.Z is an evolutionarily conserved histone H2A variant that is preferentially localized within nucleosomes at the transcriptional start site (TSS). H2A.Z reorganizes the local chromatin(More)
The histone H4 N-terminal tail has long been regarded as a major regulator in chromatin structure and function. Although the underlying mechanism has not been unraveled, an emerging body of evidence supports that H4 tail and its post-translational modification function as a recruitment motif for key factors required for proper regulation of chromatin(More)
The histone H3 amino-terminal tails play an important role in regulating chromatin transcription. Although the mechanisms by which the H3 tail modulates transcription are not well understood, recent discoveries of specific interactions of regulatory factors with H3 tails suggest that H3 tails are a key player in the precise regulation of transcription(More)