Biochemistry & Biophysics

Dorothy E. Shippen

shippen Professor of Biochemistry and Biophysics
Faculty of Genetics

Phone: (979) 862-2342
Email: dshippen@tamu.edu
Visit the Shippen lab Home Page
B.S. Auburn University (1982)
Ph.D. University of Alabama, Birmingham (1987)
Postdoc. University of California, Berkeley and
University of California, San Francisco (1987-91)

Joined Texas A&M faculty in 1991

Telomere Biology
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.

Recent Publications
  1. Surovtseva YV, Churikov D, Boltz KA, Song X, Lamb JC, Warrington R, Leehy K, Heacock M, Price CM & Shippen DE (2009) Conserved telomere maintenance component 1 interacts with STN1 and maintains chromosome ends in higher eukaryotes. Mol Cell 36: 207-18
  2. Shakirov EV, Song X, Joseph JA & Shippen DE (2009) POT1 proteins in green algae and land plants: DNA-binding properties and evidence of co-evolution with telomeric DNA. Nucleic Acids Res 37: 7455-67
  3. Shakirov EV, McKnight TD & Shippen DE (2009) POT1-independent single-strand telomeric DNA binding activities in Brassicaceae. Plant J 58: 1004-15
  4. Song X, Leehy K, Warrington RT, Lamb JC, Surovtseva YV & Shippen DE (2008) STN1 protects chromosome ends in Arabidopsis thaliana. Proc Natl Acad Sci U S A 105: 19815-20
  5. Riehs N, Akimcheva S, Puizina J, Bulankova P, Idol RA, Siroky J, Schleiffer A, Schweizer D, Shippen DE & Riha K (2008) Arabidopsis SMG7 protein is required for exit from meiosis. J Cell Sci 121: 2208-16
  6. Ming R, Hou S, Feng Y, Yu Q, Dionne-Laporte A, Saw JH, Senin P, Wang W, Ly BV, Lewis KL, Salzberg SL, Feng L, Jones MR, Skelton RL, Murray JE, Chen C, Qian W, Shen J, Du P, Eustice M, Tong E, Tang H, Lyons E, Paull RE, Michael TP, Wall K, Rice DW, Albert H, Wang ML, Zhu YJ, Schatz M, Nagarajan N, Acob RA, Guan P, Blas A, Wai CM, Ackerman CM, Ren Y, Liu C, Wang J, Wang J, Na JK, Shakirov EV, Haas B, Thimmapuram J, Nelson D, Wang X, Bowers JE, Gschwend AR, Delcher AL, Singh R, Suzuki JY, Tripathi S, Neupane K, Wei H, Irikura B, Paidi M, Jiang N, Zhang W, Presting G, Windsor A, Navajas-Pérez R, Torres MJ, Feltus FA, Porter B, Li Y, Burroughs AM, Luo MC, Liu L, Christopher DA, Mount SM, Moore PH, Sugimura T, Jiang J, Schuler MA, Friedman V, Mitchell-Olds T, Shippen DE, dePamphilis CW, Palmer JD, Freeling M, Paterson AH, Gonsalves D, Wang L & Alam M (2008) The draft genome of the transgenic tropical fruit tree papaya (Carica papaya Linnaeus). Nature 452: 991-6
  7. Kannan K, Nelson AD & Shippen DE (2008) Dyskerin is a component of the Arabidopsis telomerase RNP required for telomere maintenance. Mol Cell Biol 28: 2332-41
  8. Vespa L, Warrington RT, Mokros P, Siroky J & Shippen DE (2007) ATM regulates the length of individual telomere tracts in Arabidopsis. Proc Natl Acad Sci U S A 104: 18145-50
  9. Heacock ML, Idol RA, Friesner JD, Britt AB & Shippen DE (2007) Telomere dynamics and fusion of critically shortened telomeres in plants lacking DNA ligase IV. Nucleic Acids Res 35: 6490-500
  10. Surovtseva YV, Shakirov EV, Vespa L, Osbun N, Song X & Shippen DE (2007) Arabidopsis POT1 associates with the telomerase RNP and is required for telomere maintenance. EMBO J 26: 3653-61
  11. Watson JM & Shippen DE (2007) Telomere rapid deletion regulates telomere length in Arabidopsis thaliana. Mol Cell Biol 27: 1706-15
  12. Riha K, Heacock ML & Shippen DE (2006) The role of the nonhomologous end-joining DNA double-strand break repair pathway in telomere biology. Annu Rev Genet 40: 237-77
  13. Vespa L, Couvillion M, Spangler E & Shippen DE (2005) ATM and ATR make distinct contributions to chromosome end protection and the maintenance of telomeric DNA in Arabidopsis. Genes Dev 19: 2111-5
  14. Watson JM, Bulankova P, Riha K, Shippen DE & Vyskot B (2005) Telomerase-independent cell survival in Arabidopsis thaliana. Plant J 43: 662-74
  15. Shakirov EV, Surovtseva YV, Osbun N & Shippen DE (2005) The Arabidopsis Pot1 and Pot2 proteins function in telomere length homeostasis and chromosome end protection. Mol Cell Biol 25: 7725-33
  16. Ren S, Johnston JS, Shippen DE & McKnight TD (2004) TELOMERASE ACTIVATOR1 induces telomerase activity and potentiates responses to auxin in Arabidopsis. Plant Cell 16: 2910-22
  17. Karamysheva ZN, Surovtseva YV, Vespa L, Shakirov EV & Shippen DE (2004) A C-terminal Myb extension domain defines a novel family of double-strand telomeric DNA-binding proteins in Arabidopsis. J Biol Chem 279: 47799-807
  18. Shakirov EV & Shippen DE (2004) Length regulation and dynamics of individual telomere tracts in wild-type Arabidopsis. Plant Cell 16: 1959-67
  19. Heacock M, Spangler E, Riha K, Puizina J & Shippen DE (2004) Molecular analysis of telomere fusions in Arabidopsis: multiple pathways for chromosome end-joining. EMBO J 23: 2304-13
  20. McKnight TD & Shippen DE (2004) Plant telomere biology. Plant Cell 16: 794-803
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