- Undergraduate Education
- B.S. Auburn University (1982)
- Graduate Education
- Ph.D. University of Alabama, Birmingham (1987)
- Postdoc. University of California, Berkeley and University of California, San Francisco (1987-91)
- Joined Texas A&M in 1991
We are taking biochemical, molecular genetic and cytological approaches to study the structure, function and maintenance of telomeres. Telomeres are higher order nucleoprotein complexes that cap the ends of eukaryotic chromosomes and play essential roles in conferring genome stability and cell proliferation capacity. The protective cap of the telomere is comprised of specific telomere binding proteins that regulate the length of telomeric DNA tract and allow the cell distinguish the chromosome terminus from a double-strand break. Telomeric DNA is synthesized by the action of telomerase, an unusual reverse transcriptase that replenishes telomeric DNA lost as a consequence of replication by conventional DNA polymerases. We have developed the genetically tractable flowering plant Arabidopsis thaliana as a model system for studying telomeres in higher eukaryotes. With its sequenced genome, abundant genetic and transgenic tools, and extraordinarily high tolerance to genome instability, Arabidopsis has proven to be an excellent model for investigating fundamental processes in telomere biology. Current studies focus on defining the function and molecular evolution of telomere capping proteins and components of the telomerase ribonucleoprotein complex.
Xie, X, Shippen, DE. DDM1 guards against telomere truncation in Arabidopsis. Plant Cell Rep. 2018;37 (3):501-513.
Arora, A, Beilstein, MA, Shippen, DE. Evolution of Arabidopsis protection of telomeres 1 alters nucleic acid recognition and telomerase regulation. Nucleic Acids Res. 2016;44 (20):9821-9830.
Lee, JR, Xie, X, Yang, K, Zhang, J, Lee, SY, Shippen, DE et al.. Dynamic Interactions of Arabidopsis TEN1: Stabilizing Telomeres in Response to Heat Stress. Plant Cell. 2016;28 (9):2212-2224.
Nelson, AD, Shippen, DE. Evolution of TERT-interacting lncRNAs: expanding the regulatory landscape of telomerase. Front Genet. 2015;6 :277.
Xu, H, Nelson, AD, Shippen, DE. A transposable element within the Non-canonical telomerase RNA of Arabidopsis thaliana modulates telomerase in response to DNA damage [corrected]. PLoS Genet. 2015;11 (6):e1005281.
González-García, MP, Pavelescu, I, Canela, A, Sevillano, X, Leehy, KA, Nelson, ADL et al.. Single-cell telomere-length quantification couples telomere length to meristem activity and stem cell development in Arabidopsis. Cell Rep. 2015;11 (6):977-989.
Beilstein, MA, Renfrew, KB, Song, X, Shakirov, EV, Zanis, MJ, Shippen, DE et al.. Evolution of the Telomere-Associated Protein POT1a in Arabidopsis thaliana Is Characterized by Positive Selection to Reinforce Protein-Protein Interaction. Mol. Biol. Evol. 2015;32 (5):1329-41.
Renfrew, KB, Song, X, Lee, JR, Arora, A, Shippen, DE. POT1a and components of CST engage telomerase and regulate its activity in Arabidopsis. PLoS Genet. 2014;10 (10):e1004738.
Boltz, KA, Jasti, M, Townley, JM, Shippen, DE. Analysis of poly(ADP-Ribose) polymerases in Arabidopsis telomere biology. PLoS ONE. 2014;9 (2):e88872.
Leehy, KA, Lee, JR, Song, X, Renfrew, KB, Shippen, DE. MERISTEM DISORGANIZATION1 encodes TEN1, an essential telomere protein that modulates telomerase processivity in Arabidopsis. Plant Cell. 2013;25 (4):1343-54.