Department of Chemistry Biochemistry


Associate Professor
Ph.D., Indiana University-Bloomington, 1997

  Office: PSD-105  Lab: PS-D114
  Phone: (480) 965-3650  Lab Phone: (480) 965-1928
  Fax: (480) 965-2747

 Dr. JULIAN (JIUNN LIANG) CHEN's Lab or Group Website

Research and Teaching Interests

We are interested in understanding the structure, function and evolution of ribonucleoprotein (RNP) complexes in cells. Our attention currently focuses on the telomerase RNP enzyme, a unique reverse transcriptase essential for maintaining telomere length in most eukaryotes. Telomeres act as caps at the ends of chromosomes, and are required for chromosome stability.

Telomerase elongates telomere length by adding telomeric repeats to chromosome ends to counterbalance the natural shortening that occurs during DNA replication. Because of its role in chromosome stability, telomerase regulation is a critical step in tumorigenesis and aging. To maintain chromosome stability and infinite growth, telomerase is activated in immortal cells such as stem cells, germ line as well as 90% of human tumors. Moreover, patients with dyskeratosis congenita, a disease of premature aging, carry a mutation in the telomerase RNA (TR) or the telomerase reverse transcriptase protein (TERT) genes

Elucidation of the molecular mechanism of telomerase function is the main goal of our lab and will have significant medical implications in cancer and aging. Our goals are to understand (1) how telomerase RNP is assembled and regulated in cells, (2) how different components of the complex participate in the regulation of telomerase function, and (3) how this RNP complex evolved in different eukaryotes. Our research employes a variety of approaches involving biochemical and biophysical techniques, as well as molecular genetics and molecular biology.

Selected Publications

"Prevalent and distinct spliceosomal 3′-end processing mechanisms for fungal telomerase RNA," Qi, X., D.R. Rand, J.D. Podlevsky, Y. Li, A. Mosig, P.F. Stadler and J.J.-L. Chen, Nature Communications 6 6105 (2015)

"Telomerase mutations in smokers with emphysema.," Stanley, S.E., J.J.-L. Chen, J.D. Podlevsky, J.K. Alder, N.N. Hansel, R. Mathias, X. Qi, N.N. Rafaels, R.A. Wise, E.K. Silverman, K.C. Barnes and M. Armanios , The Journal of Clinical Investigation 125(2) 563-570 (2014)

"A self-regulating template in human telomerase.," Brown, A.F., J.D. Podlevsky, X. Qi, Y. Chen, M. Xie, and J.J.-L. Chen, Proc. Natl. Acad. Sci. U.S.A. 111(31) 11311-11316 [From the Cover] (2014)

"Structural basis for protein-RNA recognition in telomerase.," J. Huang, A.F. Brown, J. Wu, J. Xue, C.J. Bley, D.P. Rand, L. Wu, R. Zhang, J.J.-L. Chen* and M. Lei* , Nature Structural and Molecular Biology 21 507-512 (2014)

"Identification of purple sea urchin telomerase RNA using a next-generation sequencing based approach. ," Y. Li, J.D. Podlevsky, M. Marz, X. Qi, S. Hoffmann, P.F. Stadler and J.J.-L. Chen, RNA 19 852-860 (2013)

"A homozygous telomerase T motif variant resulting in markedly reduced repeat addition processivity in siblings with Hoyeraal Hreidarsson syndrome.," M.M. Gramatges, X. Qi, G.S. Sasa, J.J.-L. Chen and A.A. Bertuch, Blood 121 3586-3593 (2013)

"RNA/DNA hybrid affinity determines telomerase template-translocation efficiency," X. Qi, M. Xie, A.F. Brown, C.J. Bley, J.D. Podlevsky and J.J.-L. Chen , EMBO J. 31 150-161 (2012)

"The common ancestral core of vertebrate and fungal telomerase RNAs.," X. Qi, Y. Li, S. Honda, S. Hoffmann, M. Marz. A. Mosig, J.D. Podlevsky, P.F. Stadler, E. Selker and J.J.-L. Chen, Nucleic Acids Research 41 450-462 (2012)

"It all comes together at the ends: Structure, function, and biogenesis of telomerase," J.D. Podlevsky and J.J.-L. Chen , Mutation Research 730 3-11 (2012)

"RNA-protein binding interface in the telomerase ribonucleoprotein," C.J. Bley, X. Qi, D.P. Rand, C.R. Borges, R.W. Nelson and J.J.-L. Chen, Proc. Natl. Acad. Sci. U.S.A. 108 20333-8 (2011)

"Ancestral mutation in telomerase causes defects in repeat addition processivity and manifests as familial pulmonary fibrosis.," J.K. Alder, J.D. Cogan, A.F. Brown, C.J. Anderson, W.E. Lawson, P.M. Lansdorp, J.A. Phillips 3rd, J.E. Loyd, J.J.-L. Chen, and M.Y. Armanios , PLoS Genetics 7 e1001352 (2011)

"Syndrome complex of bone marrow failure and pulmonary fibrosis predicts germline defects in telomerase.," E.M. Parry, J.K. Alder, X. Qi, J.J.-L. Chen and M.Y. Armanios , Blood 117 5607-5611 (2011)

"A novel motif in telomerase reverse transcriptase regulates telomere repeat addition rate and processivity," M. Xie, J.D. Podlevsky, X. Qi, C.J. Bley and J.J.-L. Chen , Nucleic Acids Research 38 1982-1996 (2010)

"Evolution of vault RNAs," P.F. Stadler, J.J.-L. Chen, J. Hackermuller, S. Hoffmann, P. Khaitovich, A. Kretzschmar, A. Mosig, S.J. Prohaska, X. Qi, K. Schutt and K. Ullmann , Molecular Biology and Evolution 26 1975-1991 (2009)

"Short telomeres are a risk factor for idiopathic pulmonary fibrosis," J.K. Alder, J.J.-L. Chen, L. Lancaster, S. Danoff, S.C. Su, M. Prince, I. Vulto, M. Xie, X. Qi, R.M. Tuder, J.A. Phillips, P.M. Lansdorp, J.E. Loyd, M.Y. Armanios , Proc. Natl. Acad. Sci. U.S.A. 105 13051-13056 (2008)

"The Telomerase Database," J.D. Podlevsky, C.J. Bley, R.V. Omana, X. Qi and J.J.-L. Chen, Nucleic Acids Research, 36 D339-D343 (2008)

"Structure and function of the smallest vertebrate telomerase RNA from teleost fish," M. Xie, A. Mosig, X. Qi, Y. Li, P.F. Stadler and J.J.-L. Chen, Journal of Biological Chemistry, 283 2049-2059 (2008)

"Identification and characterization of sea squirt telomerase reverse transcriptase," Y. Li, J.A. Yates and J.J.-L. Chen, Gene 400 16-24 (2007)

"WABI2007: Homology search with fragmented nucleic acid sequence patterns. ," A. Mosig, J.J.-L. Chen and P.F. Stadler, Lect. Notes Comput. Sc. 4645 335-345 (2007)

"Telomerase mutations in families with idiopathic pulmonary fibrosis.," M. Armanios, J.J.-L. Chen, W.E. Lawson, J.K. Alder, R.G. Ingersoll, C. Markin, M. Xie, J. Cogan, J.A. Philips III, P.M. Lansdorp, C.W. Greider and J.E. Loyd, New England Journal of Medicine 356 1317-1326 (2007)

"Structure and function of eukaryotic ribonuclease P RNA," S.M. Marquez, J.-L. Chen, D. Evans and N.R. Pace, Molecular Cell 24 445-456 (cover) (2006)

"Prevalent and distinct spliceosomal 3′-end processing mechanisms for fungal telomerase RNA," Qi, X., D.R. Rand, Y. Li, J.D. Podlevsky, A. Mosig, P.F. Stadler and J.J.-L. Chen , Nature Communications (in press) (2005)

"Functional analysis of the pseudoknot structure in human telomerase RNA," J.-L. Chen and C.W. Greider, Proc. Natl. Acad. Sci. U.S.A. 102 8080-8085 (2005)

"Haploinsufficiency of hTERT leads to anticipation in autosomal dominant dyskeratosis congenital," M. Armanios, J.-L. Chen, Y.-P. Chang, R.A. Brodsky, A. Hawkins, C.A. Griffin, J.R. Eshleman, A. Chakravarti, A. Hamosh and C.W. Greider , Proc. Natl. Acad. Sci. U.S.A. 102 15960-15964 (2005)

"Telomerase biochemistry and biogenesis," J.-L. Chen and C.W. Greider , Telomeres-2nd edition 49-79 (2005)

"An emerging consensus for telomerase RNA structure," J.-L. Chen and C.W. Greider, Proc. Natl. Acad. Sci. U.S.A. 101 14683-14684 (2004)

"Telomerase RNA structure and function: implications for dyskeratosis congenita," J.-L. Chen and C.W. Greider, Trends in Biochemical Sciences 29 183-192 (2004)

"Template boundary definition in mammalian telomerase," J.-L. Chen and C.W. Greider, Genes & Development 17 2747-2752 (2003)

"Determinants in mammalian telomerase RNA that mediate enzyme processivity and cross-species incompatibility," J.-L. Chen and C.W. Greider, EMBO J. 22 304-314 (2003)

"A critical stem-loop structure in the CR4-CR5 domain of mammalian telomerase RNA," J.-L. Chen, K.K. Opperman and C.W. Greider, Nucleic Acids Research 30 592-597 (2002)

"Secondary structure of vertebrate telomerase RNA," J.-L. Chen, M.A. Blasco and C.W. Greider, Cell 100 503-514 (2000)

"Comparative photocross-linking analysis of the tertiary structures of Escherichia coli and Bacillus subtilis RNase P RNAs," Chen, J.-L., J.M. Nolan, M.E. Harris and N.R. Pace , EMBO J. 17 1515-1525 (1998)

"Identification of the universally conserved core of ribonuclease P RNA," Chen, J.-L. and N.R. Pace , RNA 3 557-560 (1997)