Richard J. Baer, PhD

  • Professor of Pathology and Cell Biology (in the Institute for Cancer Genetics)
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Academic Appointments

  • Professor of Pathology and Cell Biology (in the Institute for Cancer Genetics)

Administrative Titles

  • Deputy Director, Institute for Cancer Genetics
  • Associate Director for Basic Science, Herbert Irving Comprehensive Cancer Center


Women who carry germline mutations in the BRCA1 tumor suppressor gene are prone to develop basal-like triple-negative breast tumors, an especially lethal subtype of human breast cancer. Richard Baer studies the mechanisms by which BRCA1 suppresses tumor formation and how these mechanisms are disrupted in BRCA1 mutation carriers. In vivo, BRCA1 exists in the form of a heterodimer with another structurally-related tumor suppressor, the BARD1 protein. Most of the cellular functions attributed to BRCA1, including its critical activities in genome stability and tumor suppression, are mediated by the BRCA1/BARD1 heterodimer. The Baer laboratory uses biochemical, cellular, and organismal approaches to characterize the BRCA1/BARD1 complex and its associated factors, such as the DNA repair protein CtIP. These studies seek to define the biological functions of the BRCA1/BARD1 pathway, particularly with respect to maintenance of genome stability, and how the loss of these functions promotes breast and ovarian cancer.

Selected Publications

  1. CtIP is essential for early B cell proliferation and development in mice
    Liu X, Wang XS, Lee BJ, Wu-Baer FK, Lin X, Shao Z, Estes VM, Gautier J, Baer R, Zha S
    J Exp Med. 2019.
    PMID: 31097467, DOI: 10.1084/jem.20181139
  2. The BRCT Domains of the BRCA1 and BARD1 Tumor Suppressors Differentially Regulate Homology-Directed Repair and Stalled Fork Protection
    Billing D, Horiguchi M, Wu-Baer F, Taglialatela A, Leuzzi G, Nanez SA, Jiang W, Zha S, Szabolcs M, Lin CS, Ciccia A, Baer R
    Mol Cell. 2018.
    PMID: 30244837, DOI: 10.1016/j.molcel.2018.08.016
  3. Genomic instability during reprogramming by nuclear transfer is DNA replication dependent
    Chia G, Agudo J, Treff N, Sauer MV, Billing D, Brown BD, Baer R, Egli D
    Nat Cell Biol. 2017.
    PMID: 28263958, DOI: 10.1038/ncb3485
  4. The interaction between CtIP and BRCA1 is not essential for resection-mediated DNA repair or tumor suppression
    Reczek CR, Szabolcs M, Stark JM, Ludwig T, Baer R
    J Cell Biol. 2013.
    PMID: 23712259, DOI: 10.1083/jcb.201302145
  5. BRCA1 tumor suppression depends on BRCT phosphoprotein binding, but not its E3 ligase activity
    Shakya R, Reid LJ, Reczek CR, Cole F, Egli D, Lin CS, deRooij DG, Hirsch S, Ravi K, Hicks JB, Szabolcs M, Jasin M, Baer R, Ludwig T
    Science. 2011.
    PMID: 22034435, DOI: 10.1126/science.1209909
  6. The basal-like mammary carcinomas induced by Brca1 or Bard1 inactivation implicate the BRCA1/BARD1 heterodimer in tumor suppression
    Shakya R, Szabolcs M, McCarthy E, Ospina E, Basso K, Nandula S, Murty V, Baer R, Ludwig T
    Proc Natl Acad Sci USA. 2008.
    PMID: 18443292, DOI: 10.1073/pnas.0711032105
  7. Structural requirements for the BARD1 tumor suppressor in chromosomal stability and homology-directed DNA repair
    Laufer M, Nandula SV, Modi AP, Wang S, Jasin M, Murty VV, Ludwig T, Baer R
    J Biol Chem. 2007.
    PMID: 17848578, DOI: 10.1074/jbc.M705198200
  8. The BRCA1/BARD1 heterodimer assembles polyubiquitin chains through an unconventional linkage involving lysine residue K6 of ubiquitin
    Wu-Baer F, Lagrazon K, Yuan W, Baer R
    J Biol Chem. 2003.
    PMID: 12890688, DOI: 10.1074/jbc.C300249200
  9. The BRCA1/BARD1 heterodimer, a tumor suppressor complex with ubiquitin E3 ligase activity
    Baer R, Ludwig T
    Curr Opin Genet Dev. 2002.
    PMID: 11790560, DOI: 10.1016/s0959-437x(01)00269-6
  10. The C-terminal (BRCT) domains of BRCA1 interact in vivo with CtIP, a protein implicated in the CtBP pathway of transcriptional repression
    Yu X, Wu LC, Bowcock AM, Aronheim A, Baer R
    J Biol Chem. 1998.
    PMID: 9738006, DOI: 10.1074/jbc.273.39.25388
  11. Identification of a RING protein that can interact in vivo with the BRCA1 gene product
    Wu LC, Wang ZW, Tsan JT, Spillman MA, Phung A, Xu XL, Yang MC, Hwang LY, Bowcock AM, Baer R
    Nat Genet. 1996.
    PMID: 8944023, DOI: 10.1038/ng1296-430
  12. TAL1, TAL2 and LYL1: a family of basic helix-loop-helix proteins implicated in T cell acute leukaemia
    Baer R
    Semin Cancer Biol. 1993.
    PMID: 8142619, DOI:
  13. TAL2, a helix-loop-helix gene activated by the (7;9)(q34;q32) translocation in human T-cell leukemia
    Xia Y, Brown L, Yang CY, Tsan JT, Siciliano MJ, Espinosa R, Le Beau MM, Baer RJ
    Proc Natl Acad Sci USA. 1991.
    PMID: 1763056, DOI: 10.1073/pnas.88.24.11416
  14. Site-specific recombination of the tal-1 gene is a common occurrence in human T cell leukemia
    Brown L, Cheng JT, Chen Q, Siciliano MJ, Crist W, Buchanan G, Baer R
    EMBO J. 1990.
    PMID: 2209547
  15. The tal gene undergoes chromosome translocation in T cell leukemia and potentially encodes a helix-loop-helix protein
    Chen Q, Cheng JT, Tasi LH, Schneider N, Buchanan G, Carroll A, Crist W, Ozanne B, Siciliano MJ, Baer R
    EMBO J. 1990.
    PMID: 2303035