Dr. Doublié 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.

Research Interests

Modifications in 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 generate and 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. We aim to elucidate at the atomic level the factors that influence the interactions between a replicative polymerase and DNA lesions. Our goal is to answer the following questions: How does a DNA polymerase sense the presence of a DNA lesion? What role does sequence context play in translesion synthesis? What triggers the transfer of DNA to the editing site in the event of a base mispair ?

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. The goal of this project is to delineate the structural features of the 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 are able to recognize vastly different substrates.

Messenger RNA (mRNA) also undergoes modifications, this time as an essential step of the normal cell program. During processing of the 3'-end of mRNA, a specific endonucleolytic cleavage event precedes the addition of a poly(A) tail. Such maturation of 3'-ends is a key regulatory step in the expression of many genes. The cleavage and polyadenylation reactions are carried out by a multicomponent machinery of remarkable complexity. Our goal is to understand how the different components of the machinery interact to cleave then polyadenylate messenger RNAs.

Selected Publications

Aller, P., Rould, M.A., Hogg, M., Wallace, S.S. and Doublié, S. A structural rationale for stalling of a replicative DNA polymerase at the most common oxidative thymine lesion, thymine glycol. PNAS 2007 104:814-818 View the structure at PDB.

Coseno, M. E., Martin, G., Gilmartin, G., Keller, W. and Doublié, S. Crystal Structure of the 25 kDa Subunit of Human Cleavage Factor Im. Nucleic Acids Res 2008 Jun;36(10):3474-3483 View the structure at PDB

Imamura, K., Wallace, S.S. and Doublié, S. Structural characterization of a viral NEIL1 ortholog unliganded and bound to abasic site-containing DNA. J Biol Chem. 2009 Jul 22. [Epub ahead of print] View the structure at PDB.

Faucher, F., Duclos, S., Bandaru, V., Wallace, S.S. and Doublié, S. Crystal structures of two archaeal 8-oxoguanine DNA glycosylases provide structural insight into guanine/8-oxoguanine distinction. Structure. 2009 May 13;17(5):703-12. View the structure at PDB.

Faucher, F., Robey-Bond, S.M., Wallace, S.S. and Doublié, S. Structural characterization of Clostridium acetobutylicum 8-oxoguanine DNA glycosylase in its apo form and in complex with 8-oxodeoxyguanosine. J Mol Biol. 2009 Apr 3;387(3):669-79. Epub 2009 Feb 9. View the structure at PDB.

CMB Lab Members