{
    "abstract": "C/EBP\u03b1 plays a key role in specifying myeloid lineage development. HoxA9 is expressed in myeloid progenitors, with its level diminishing during myeloid maturation, and HOXA9 is over-expressed in a majority of acute myeloid leukemia cases, including those expressing NUP98-HOXD13. The objective of this study was to determine whether HoxA9 directly represses Cebpa gene expression. We find 4-fold increased HoxA9 and 5-fold reduced Cebpa in marrow common myeloid and LSK progenitors from Vav-NUP98-HOXD13 transgenic mice. Conversely, HoxA9 decreases 5-fold while Cebpa increases during granulocytic differentiation of 32Dcl3 myeloid cells. Activation of exogenous HoxA9-ER in 32Dcl3 cells reduces Cebpa mRNA even in the presence of cycloheximide, suggesting direct repression. Cebpa transcription in murine myeloid cells is regulated by a hematopoietic-specific +37 kb enhancer and by a more widely active +8 kb enhancer. ChIP-Seq analysis of primary myeloid progenitor cells expressing exogenous HoxA9 or HoxA9-ER demonstrates that HoxA9 localizes to both the +8 kb and +37 kb Cebpa enhancers. Gel shift analysis demonstrates HoxA9 binding to three consensus sites in the +8 kb enhancer, but no affinity for the single near-consensus site present in the +37 kb enhancer. Activity of a Cebpa +8 kb enhancer/promoter-luciferase reporter in 32Dcl3 or MOLM14 myeloid cells is increased ~2-fold by mutation of its three HOXA9-binding sites, suggesting that endogenous HoxA9 represses +8 kb Cebpa enhancer activity. In contrast, mutation of five C/EBP\u03b1-binding sites in the +8 kb enhancer reduces activity 3-fold. Finally, expression of a +37 kb enhancer/promoter-hCD4 transgene reporter is reduced ~2-fold in marrow common myeloid progenitors when the Vav-NUP98-HOXD13 transgene is introduced. Overall, these data support the conclusion that HoxA9 represses Cebpa expression, at least in part via inhibition of its +8 kb enhancer, potentially allowing normal myeloid progenitors to maintain immaturity and contributing to the pathogenesis of acute myeloid leukemia associated with increased HOXA9.",
    "authors": [
        {
            "affiliation": "Division of Pediatric Oncology, Johns Hopkins University, Baltimore, Maryland, United States of America.",
            "firstname": "Lei",
            "initials": "L",
            "lastname": "Peng"
        },
        {
            "affiliation": "Division of Pediatric Oncology, Johns Hopkins University, Baltimore, Maryland, United States of America.",
            "firstname": "Hong",
            "initials": "H",
            "lastname": "Guo"
        },
        {
            "affiliation": "Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, Indiana, United Sates of America.",
            "firstname": "Peilin",
            "initials": "P",
            "lastname": "Ma"
        },
        {
            "affiliation": "Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, Indiana, United Sates of America.",
            "firstname": "Yuqing",
            "initials": "Y",
            "lastname": "Sun"
        },
        {
            "affiliation": "Division of Pediatric Oncology, Johns Hopkins University, Baltimore, Maryland, United States of America.",
            "firstname": "Lauren",
            "initials": "L",
            "lastname": "Dennison"
        },
        {
            "affiliation": "Genetics Branch, Center for Cancer Research, NCI/NIH, Bethesda, Maryland, United States of America.",
            "firstname": "Peter D",
            "initials": "PD",
            "lastname": "Aplan"
        },
        {
            "affiliation": "Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, Indiana, United Sates of America.",
            "firstname": "Jay L",
            "initials": "JL",
            "lastname": "Hess"
        },
        {
            "affiliation": "Division of Pediatric Oncology, Johns Hopkins University, Baltimore, Maryland, United States of America.",
            "firstname": "Alan D",
            "initials": "AD",
            "lastname": "Friedman"
        }
    ],
    "conclusions": null,
    "copyrights": null,
    "doi": "10.1371/journal.pone.0217604\n10.1038/leu.2008.198\n10.1038/onc.2015.174\n10.1182/blood-2011-03-341081\n10.1182/bloodadvances.2018025866\n10.1016/j.ccell.2018.06.010\n10.1182/blood-2007-09-113597\n10.1007/s12185-015-1764-6\n10.1182/blood-2011-12-397091\n10.1371/journal.pone.0126385\n10.1371/journal.pone.0150809\n10.1182/blood-2016-01-695759\n10.1182/blood-2004-12-4794\n10.1182/blood-2002-08-2484\n10.3324/haematol.13042\n10.1073/pnas.0804507105\n10.1073/pnas.1402238111\n10.1074/jbc.272.13.8198\n10.1101/gad.1103303\n10.1093/nar/gkr024\n10.1182/blood-2017-07-795757\n10.1038/leu.2012.49\n10.4049/jimmunol.1800244\n10.1101/gad.1111603",
    "journal": "PloS one",
    "keywords": [],
    "methods": null,
    "publication_date": "2019-05-24",
    "pubmed_id": "31120998\n7527557\n11823037\n10374871\n10521349\n18668134\n26028034\n22072553\n30463913\n30270123\n19056693\n25753223\n22451420\n25938608\n26937964\n26966090\n15755899\n24868087\n12543865\n18603548\n18768819\n24958854\n9729718\n9079637\n12923056\n19651302\n21317192\n29343483\n22343733\n30061199\n9058712\n11438208\n12952893\n2006196\n1391942\n12949251",
    "results": null,
    "title": "HoxA9 binds and represses the Cebpa +8 kb enhancer.",
    "xml": "<Element 'PubmedArticle' at 0x788504607740>"
}