Dr. Sylvie Doublie

Dr. Sylvie  Doublie
Professor

 

Structural Biology of DNA Replication and Repair

Modifications to DNA or RNA, as part of normal cellular processes or as aberrations, can have profound biological consequences. The major thrust of my research program is to study these nucleic acid modifications in the context of the enzymes and proteins that either generate or recognize them.

DNA polymerases, which otherwise faithfully replicate DNA, stumble when they encounter oxidative DNA lesions. Polymerases either will be blocked at the site of lesion, or bypass it. The latter case, referred to as translesion synthesis, may initiate an oncogenic process if the wrong base is inserted opposite the lesion. Uncovering the fundamental mechanisms underpinning translesion synthesis is paramount to understand the initial events of mutagenesis. Our work currently focuses on human DNA polymerases, including DNA polymerases beta and theta, which function in lesion repair or bypass respectively. We aim to elucidate at the atomic level how germline and somatic mutations affect polymerase function. We also seek to uncover how pol theta functions in double-strand break repair.

Several DNA repair mechanisms are in place to minimize damage in DNA before DNA polymerases replicate the genome. One of these processes is called Base Excision Repair (BER). The first step in BER is carried out by DNA glycosylases, so named because they hydrolyze the N-glycosidic bond between a damaged base and its deoxyribose, leaving an apurinic or apyrimidinic site in DNA. Our goal is to delineate the structural features of the human DNA glycosylases that are involved in recognition of DNA base damage produced by ionizing radiation. In particular, we intend to address the question of how enzymes with a similar active site architecture recognize vastly different substrates. Our focus is on human DNA glycosylases that repair oxidized lesions: the Nei-like enzymes (NEIL1-3), and Nth-like 1 NTHL1 glycosylase.

Crystal structure of human DNA polymerase theta

Crystal structure of human DNA polymerase theta

Crystal structure of mammalian NEIL3 DNA glycosylase

Crystal structure of mammalian NEIL3 DNA glycosylase


Office:
E314A Given
802-656-9531
Sylvie.Doublie@uvm.edu

Lab:
E314 Given
802-656-9533

BACKGROUND

Dr. Doublie received her Ph.D. in Biochemistry and Biophysics in 1993 under the direction of Charles W. Carter at the University of North Carolina at Chapel Hill. She did postdoctoral work with Stephen Cusack at the EMBL outstation in Grenoble and with Tom Ellenberger at Harvard Medical School where she solved the crystal structure of the ternary complex of T7 DNA polymerase. She joined the UVM faculty in October 1998.

LAB MEMBERS

Vy Cao
        Research Technician
Brittany Carroll
        Graduate Student
Brian E. Eckenroth
        Research Specialist
Ethan Loo
        Undergraduate Student
Andrew Malaby
        Postdoctoral Fellow
Kedar Moharana
        Postdoctoral Fellow

SELECTED PUBLICATIONS

Zahn KE, Averill AM, Aller P, Wood RD, Doublie S. Human DNA polymerase theta grasps the primer terminus to mediate DNA repair. Nat Struct Mol Biol. 2015 Apr;22(4):304-11

Eckenroth BE, Fleming AM, Sweasy JB, Burrows CJ, Doublie S. Crystal structure of DNA polymerase beta with DNA containing the base lesion spiroiminodihydantoin in a templating position. Biochemistry. 2014 Apr 8;53(13):2075-7

Liu M, Imamura K, Averill AM, Wallace SS, Doublie S. Structural characterization of a mouse ortholog of human NEIL3 with a marked preference for single-stranded DNA. Structure. 2013 Feb 5;21(2):247-56

Yang Q, Coseno M, Gilmartin GM, Doublie S. Crystal structure of a human cleavage factor CFI(m)25/CFI(m)68/RNA complex provides an insight into poly(A) site recognition and RNA looping. Structure. 2011 Mar 9;19(3):368-77.

Hyde SJ, Eckenroth BE, Smith BA, Eberley WA, Heintz NH, Jackman JE, Doublie S. tRNAHis guanylyltransferase (THG1), a unique 3′-5′ nucleotidyl transferase, shares unexpected structural homology with canonical 5′-3′ DNA polymerases. Proc Natl Acad Sci U S A. 2010 Nov 23;107(47):20305-10

All Doublie publications