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Elizabeth Boehm

Mentor: M. Todd Washington, PhD

Year Entered Into Program: 2012

PhD Institution: University of Iowa, 2016

Affiliations

  • Department of Biochemistry

Research Description

Studies on the recruitment and regulation of Y-family polymerases

The main goal of my PhD thesis was to study the regulation of translesion synthesis (TLS) through the recruitment and assembly of macromolecular complexes including Y-family polymerases (polκ, polη, polι, Rev1, and pol ζ) to ubiquitin-modified PCNA (ubPCNA) at stalled replication forks.  I first studied the interaction between yeast pol η and yeast Rev1 and determined that the PCNA-interacting-protein (PIP) motif of pol η also binds the C-terminal domain of Rev1.  This was the first instance of a PIP motif binding a protein other than PCNA.  I additionally showed that Rev1-interacting regions (RIRs) in the human Y-family polymerases are also able to interact with PCNA, a fact that had not been previously appreciated.  Using single molecule total internal reflection fluorescence (TIRF) microscopy, I provided the first evidence for PCNA tool belts and Rev1 polymerase bridges in a eukaryotic system.  These architectures, which are dynamic and can interconvert, provide a mechanism by which PCNA can bind to so many target proteins simultaneously and how polymerase switches can occur through the Y-family polymerases binding the Rev1 CTD.  Finally, I identified a novel ubiquitin binding motif on the catalytic core of yeast pol η.  Substitution of highly conserved residues within this motif lead to loss of pol η activity in vivo, as well as an inability of pol η to be stimulated in the presence of UbPCNA.  Taken together, my thesis work has made significant progress towards understanding the regulation of the Y-family polymerases through their binding to and activation by PCNA. 

Awards/Accomplishments

  • Panelist: Biochemistry Graduate Student Panel Discussion Series, University of Iowa, Nov 2020
  • NIH T32 Predoctoral Fellowship in Pharmacological Sciences (GM067795), University of Iowa, 2013-2015
  • Graduate Research Excellence Award Nominee for Biochemistry-Spring 2015
  • Lasker Foundation Essay Contest, 2nd place-Fall 2014, Spring 2015

Publications

  1. Dieckman LM,* Boehm EM*, Hingorani M, Washington MT. Distinct structural alterations in proliferating cell nuclear antigen (PCNA) block DNA mismatch repair. Biochemistry, 52(33):5611-5619, 2013.  PMCID: PMC3845532  (* these authors contributed equally to the work)
  2. Pryor JM, Dieckman LM, Boehm EM, and Washington MT. Eukaryotic Y-Family Polymerases: A Biochemical and Structural Perspective. Nucl. Acids Mol. Biol. (Springer Book), 2013
  3. Boehm EM, Powers KT, Spies M, Houtman JCD, and Washington MT. The Proliferating Cell Nuclear Antigen (PCNA)-interacting peptide (PIP) motif of DNA polymerase eta binds Rev1. J Biol Chem 291(16):8735-44, 2016.  PMCID: PMC4861442
  4. Boehm EM, Gildenberg MS, and Washington MT. The many roles of PCNA in DNA replication. Enzymes 39:231-54, 2016.  PMCID: PMC4890617
  5. Boehm EM, Spies M, and Washington MT. PCNA tool belts and Polymerase bridges form and interconvert in translesion synthesis complexes. Nucleic Acids Res 44(17):8250-60, 2016.  PMCID: PMC5041468
  6. Kondratick CM, Boehm EM, Dieckman LM, Powers KT, Sanchez JS, Mueting SR, and Washington MT. Identification of new mutations at the PCNA subunit interface that block translesion synthesis. PLoS One 11(6):e0157023, 2016.  PMCID: PMC4892588
  7. ​Boehm EM, Washington MT. R.I.P. to the PIP: PCNA-binding motif no longer considered specific: PIP motifs and other related sequences are not distinct entities and can bind multiple proteins involved in genome maintenance. Bioessays 38(11):1117-1122, 2016.  PMCID: PMC5341575
  8. Boehm EM, Subramanyam S, Ghoneim M, Washington MT, Spies M. Quantifying the Assembly of Multicomponent Molecular Machines by Single-Molecule Total Internal Reflection Fluorescence Microscopy. Methods Enzymol 581:105-145, 2016.  PMCID: PMC5403009
     

Research