Publications

Journal Articles


  • A LncRNA-MAF:MAFB Transcription Factor Network Regulates Epidermal Differentiation DEVELOPMENTAL CELL Lopez-Pajares, V., Qu, K., Zhang, J., Webster, D. E., Barajas, B. C., Siprashvili, Z., Zarnegar, B. J., Boxer, L. D., Rios, E. J., Tao, S., Kretz, M., Khavari, P. A. 2015; 32 (6): 693-706

    Abstract

    Progenitor differentiation requires remodeling of genomic expression; however, in many tissues, such as epidermis, the spectrum of remodeled genes and the transcription factors (TFs) that control them are not fully defined. We performed kinetic transcriptome analysis during regeneration of differentiated epidermis and identified gene sets enriched in progenitors (594 genes), in early (159 genes), and in late differentiation (387 genes). Module mapping of 1,046 TFs identified MAF and MAFB as necessary and sufficient for progenitor differentiation. MAF:MAFB regulated 393 genes altered in this setting. Integrative analysis identified ANCR and TINCR lncRNAs as essential upstream MAF:MAFB regulators. ChIP-seq analysis demonstrated MAF:MAFB binding to known epidermal differentiation TF genes whose expression they controlled, including GRHL3, ZNF750, KLF4, and PRDM1. Each of these TFs rescued expression of specific MAF:MAFB target gene subsets in the setting of MAF:MAFB loss, indicating they act downstream of MAF:MAFB. A lncRNA-TF network is thus essential for epidermal differentiation.

    View details for DOI 10.1016/j.devcel.2015.01.028

    View details for Web of Science ID 000351841900008

    View details for PubMedID 25805135

  • ZNF750 interacts with KLF4 and RCOR1, KDM1A, and CTBP1/2 chromatin regulators to repress epidermal progenitor genes and induce differentiation genes GENES & DEVELOPMENT Boxer, L. D., Barajas, B., Tao, S., Zhang, J., Khavari, P. A. 2014; 28 (18): 2013-2026
  • ZNF750 interacts with KLF4 and RCOR1, KDM1A, and CTBP1/2 chromatin regulators to repress epidermal progenitor genes and induce differentiation genes. Genes & development Boxer, L. D., Barajas, B., Tao, S., Zhang, J., Khavari, P. A. 2014; 28 (18): 2013-26

    Abstract

    ZNF750 controls epithelial homeostasis by inhibiting progenitor genes while inducing differentiation genes, a role underscored by pathogenic ZNF750 mutations in cancer and psoriasis. How ZNF750 accomplishes these dual gene regulatory impacts is unknown. Here, we characterized ZNF750 as a transcription factor that binds both the progenitor and differentiation genes that it controls at a CCNNAGGC DNA motif. ZNF750 interacts with the pluripotency transcription factor KLF4 and chromatin regulators RCOR1, KDM1A, and CTBP1/2 through conserved PLNLS sequences. ChIP-seq (chromatin immunoprecipitation [ChIP] followed by high-throughput sequencing) and gene depletion revealed that KLF4 colocalizes ∼10 base pairs from ZNF750 at differentiation target genes to facilitate their activation but is unnecessary for ZNF750-mediated progenitor gene repression. In contrast, KDM1A colocalizes with ZNF750 at progenitor genes and facilitates their repression but is unnecessary for ZNF750-driven differentiation. ZNF750 thus controls differentiation in concert with RCOR1 and CTBP1/2 by acting with either KDM1A to repress progenitor genes or KLF4 to induce differentiation genes.

    View details for DOI 10.1101/gad.246579.114

    View details for PubMedID 25228645

  • ZNF750 Is a p63 Target Gene that Induces KLF4 to Drive Terminal Epidermal Differentiation DEVELOPMENTAL CELL Sen, G. L., Boxer, L. D., Webster, D. E., Bussat, R. T., Qu, K., Zarnegar, B. J., Johnston, D., Siprashvili, Z., Khavari, P. A. 2012; 22 (3): 669-677

    Abstract

    Disrupted epidermal differentiation characterizes numerous diseases that impact >25% of the population. In a search for dominant mediators of differentiation, we defined a requirement for ZNF750 in terminal epidermal differentiation. ZNF750 controlled genes mutated in numerous human skin diseases, including FLG, LOR, LCE3B, ALOXE3, and SPINK5. ZNF750 induced progenitor differentiation via an evolutionarily conserved C2H2 zinc finger motif. The epidermal master regulator, p63, bound the ZNF750 promoter and was necessary for its induction. ZNF750 restored differentiation to p63-deficient tissue, suggesting that it acts downstream of p63. A search for functionally important ZNF750 targets via analysis of ZNF750-regulated genes identified KLF4, a transcription factor that activates late epidermal differentiation. ZNF750 binds to KLF4 at multiple sites flanking the transcriptional start site and controls its expression. ZNF750 thus directly links a tissue-specifying factor, p63, to an effector of terminal differentiation, KLF4, and represents a potential future target for disorders of this process.

    View details for DOI 10.1016/j.devcel.2011.12.001

    View details for Web of Science ID 000301701600020

    View details for PubMedID 22364861

  • Cell cycle-dependent deacetylation of telomeric histone H3 lysine K56 by human SIRT6 CELL CYCLE Michishita, E., McCord, R. A., Boxer, L. D., Barber, M. F., Hong, T., Gozani, O., Chua, K. F. 2009; 8 (16): 2664-2666

    View details for Web of Science ID 000268983900036

    View details for PubMedID 19625767

  • SIRT6 Links Histone H3 Lysine 9 Deacetylation to NF-kappa B-Dependent Gene Expression and Organismal Life Span CELL Kawahara, T. L., Michishita, E., Adler, A. S., Damian, M., Berber, E., Lin, M., McCord, R. A., Ongaigui, K. C., Boxer, L. D., Chang, H. Y., Chua, K. F. 2009; 136 (1): 62-74

    Abstract

    Members of the sirtuin (SIRT) family of NAD-dependent deacetylases promote longevity in multiple organisms. Deficiency of mammalian SIRT6 leads to shortened life span and an aging-like phenotype in mice, but the underlying molecular mechanisms are unclear. Here we show that SIRT6 functions at chromatin to attenuate NF-kappaB signaling. SIRT6 interacts with the NF-kappaB RELA subunit and deacetylates histone H3 lysine 9 (H3K9) at NF-kappaB target gene promoters. In SIRT6-deficient cells, hyperacetylation of H3K9 at these target promoters is associated with increased RELA promoter occupancy and enhanced NF-kappaB-dependent modulation of gene expression, apoptosis, and cellular senescence. Computational genomics analyses revealed increased activity of NF-kappaB-driven gene expression programs in multiple Sirt6-deficient tissues in vivo. Moreover, haploinsufficiency of RelA rescues the early lethality and degenerative syndrome of Sirt6-deficient mice. We propose that SIRT6 attenuates NF-kappaB signaling via H3K9 deacetylation at chromatin, and hyperactive NF-kappaB signaling may contribute to premature and normal aging.

    View details for DOI 10.1016/j.cell.2008.10.052

    View details for Web of Science ID 000262318400015

    View details for PubMedID 19135889

  • SIRT6 stabilizes DNA-dependent protein kinase at chromatin for DNA double-strand break repair AGING-US McCord, R. A., Michishita, E., Hong, T., Berber, E., Boxer, L. D., Kusumoto, R., Guan, S., Shi, X., Gozani, O., Burlingame, A. L., Bohr, V. A., Chua, K. F. 2009; 1 (1): 109-121

    Abstract

    The Sir2 chromatin regulatory factor links maintenance of genomic stability to life span extension in yeast. The mammalian Sir2 family member SIRT6 has been proposed to have analogous functions, because SIRT6-deficiency leads to shortened life span and an aging-like degenerative phenotype in mice, and SIRT6 knockout cells exhibit genomic instability and DNA damage hypersensitivity. However, the molecular mechanisms underlying these defects are not fully understood. Here, we show that SIRT6 forms a macromolecular complex with the DNA double-strand break (DSB) repair factor DNA-PK (DNA-dependent protein kinase) and promotes DNA DSB repair. In response to DSBs, SIRT6 associates dynamically with chromatin and is necessary for an acute decrease in global cellular acetylation levels on histone H3 Lysine 9. Moreover, SIRT6 is required for mobilization of the DNA-PK catalytic subunit (DNA-PKcs) to chromatin in response to DNA damage and stabilizes DNA-PKcs at chromatin adjacent to an induced site-specific DSB. Abrogation of these SIRT6 activities leads to impaired resolution of DSBs. Together, these findings elucidate a mechanism whereby regulation of dynamic interaction of a DNA repair factor with chromatin impacts on the efficiency of repair, and establish a link between chromatin regulation, DNA repair, and a mammalian Sir2 factor.

    View details for Web of Science ID 000276347200013

    View details for PubMedID 20157594

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