Michele KlingbeilAssistant Professor Phone: 413-577-3823 Ph.D.: Cell and Molecular Biology, University of Toledo, 1996 Postoctoral Training: Department of Biological Chemistry, Johns Hopkins School of Medicine |
|
Parasitology, the replication and repair of mitochondrial DNA (kinetoplast DNA network) in African trypanosomes How is the kDNA network replicated? Key to the mechanism of network replication is the release of
minicircles from the kDNA network into the specialized kinetoflagellar
zone to replicate as free circular molecules, and their subsequent
reattachment at the network periphery. Using a combination of reverse genetics (RNAi), cell biology and biochemistry,
we would like to answer several questions. What specific roles do the
Pol I-like proteins play in replication and repair? What enzymatic properties
distinguish between replication and repair functions? What other interacting
proteins are required for kDNA replication and repair? Most importantly,
are there inhibitors specific to these Pol I-like proteins? |
|
Selected PublicationsKlingbeil, MM, Burton , P, Barnes, R and McCulloch, R (2007) The Three R's of the Trypanosomatid Genomes: Replication, Recombination and Repair. In: Trypanosomes – After the Genome (Barry, D, Mottram, J, McCulloch, R and Acosta-Serrano, A, eds.), Horizon Scientific Press, Norwich , UK . pp 129-171. In press. El-Sayed, NMA, Myler PJ, Bartholomeu DC, Klingbeil, MM, Fraser, C, Stuart, KD and Andersson, B (2005) The genome sequence of Trypansoma cruzi, etiological agent of Chagas disease. Science 309, 409-415. (Part of Special Science section) Klingbeil, MM and Englund PT (2004) Closing the gaps in kinetoplast DNA replication. Proc. Natl. Acad. Sci. USA 10, 4333-4334. Saxowsky, TM, Choudhary, G, Klingbeil, MM and Englund PT (2003) Trypanosoma brucei has two distinct mitochondrial DNA polymerase beta enzymes. J. Biol. Chem. 278, 49095-49101. Klingbeil, MM, Motyka,SA, and Englund PT (2002) Multiple mitochondrial DNA polymerases from Trypanosoma brucei. Mol. Cell 10, 175-186 (July, Cover image). Klingbeil, MM, Drew, ME, Liu, Y, Morris, JC, Motyka, SA, Saxowsky, TT, Wang, Z, and Englund PT (2001) Unlocking the secrets of trypanosome kinetoplast DNA network replication. Protist 152, 255-262. Morris, JC, Drew, ME, Klingbeil, MM, Motyka, SA, Saxowsky, TT, Wang, Z, and Englund, PT (2001) Replication of kinetoplast DNA: an update for the new millennium. Intl. J. Parasitol. 31, 453-458. Huang, YJ, Walker , D, Chen, W, Klingbeil, M, and Komuniecki, R (1998) Expression of pyruvate dehydrogenase isoforms during the aerobic/anaerobic transition in the development of the parasitic nematode Ascaris suum : altered stoichiometry of phosphorylation/inactivation. Arch. Biochem. Biophys. 352, 263-270. Klingbeil, MM, Walker , DJ, Huang, YJ and Komuniecki, R (1997) Altered phosphorylation/ inactivation of a novel pyruvate dehydrogenase in adult Ascaris suum muscle. Mol. Biochem. Parasit . 90 , 323-326. Klingbeil MM, Walker, DJ, Arnette, R, Sidawy, E, Hayton, K, Komuniecki, PR and Komuniecki R (1996) Identification of a novel, dihydrolipoyl dehydrogenase-binding protein in the pyruvate dehydrogenase complex of the anaerobic parasitic nematode, Ascaris suum . J. Biol. Chem . 271 , 5451-5457. Komuniecki, R, Klingbeil, M, Arnette, R, Walker , D, and Diaz, F (1996) Regulation of the pyruvate dehydrogenase complex during the aerobic/anaerobic transition in the development of the parasitic nematode Ascaris suum . In: Alpha-keto Acid Dehydrogenase Complexes ( Patel , MS , Roche, TE and Harris, RA, eds.), Birkhauser, Verlag, AG, pp. 93-100. Duran, E, Komuniecki, RW, Komuniecki, PR, Wheelock, MJ, Klingbeil, MM, Ma, Y, and Johnson, KJ (1993) Characterization of cDNA clones for the 2-methyl-branched chain enoyl-CoA reductase. J. Biol. Chem. 268 , 22391-22395. |
|
Trypanosomatid
parasites (Trypanosoma and Leishmania species) cause deadly diseases
in humans and livestock. Current treatments are often toxic and difficult
to administer in endemic regions (mainly Third World countries).
The
need for new anti-trypanosomatid drugs has never been greater. As one
of the earliest branching eukaryotic lineages, trypanosomes display
a number of unusual biological properties. One property without counterpart
in nature is their amazing mitochondrial DNA known as kinetoplast DNA
(kDNA). The kDNA is a network containing thousands of catenated DNA
molecules (minicircles and maxicircles, figure at left). We are interested
in studying proteins involved in replicating this novel structure. Our
primary focus is on a family of 4 DNA polymerases (Pol) from Trypanosoma
brucei (Klingbeil et al., Mol. Cell 10, p. 175-186, figure at right)
that are related to bacterial Pol I, all of which localize to the mitochondrion.This
Pol I-like family is present in all the major trypanosomatid parasites,
but not in mammals. 
Several
proteins localize to specific regions surrounding the condensed
kDNA disk including 2 of the Pol I-like proteins (figure at right).
Genetic studies using RNA interference (RNAi) indicate that Pol
IB and Pol IC are involved in minicircle replication and essential
for parasite survival. The other 2 polymerases could be involved
in kDNA repair. In mammals, Pol gamma is the only DNA polymerase
involved in mitochondrial DNA replication. Trypanosomatid parasites
lack Pol gamma, but the Pol I-like family represents another intriguing
property of trypanosomes different from the mammalian host, that
serve as an attractive new drug target with broad applications
to potentially treat several trypanosomatid parasitic diseases. Mailing Address
Michele Klingbeil
Department of Microbiology
203 Morrill Science Center IVN
University of Massachusetts
639 North Pleasant Street
Amherst, MA 01003
|
|
|
|
|
