Book of Abstracts: Albany 2007

category image Albany 2007
Conversation 15
June 19-23 2007

Modeling Pseudoknot Structures from Telomerase RNAs of Ciliates

Telomerase, a ribonucleoprotein complex, is responsible for the maintenance of telomeres, the ends of linear chromosomes. Telomerase RNA, a central component of this complex, is highly divergent in sequence and even in length among different organisms: it is 150-220 nt long in ciliates, 380-560 nt in vertebrates and 930-1540 nt in yeast. Nevertheless, certain structural elements appear to be conserved, despite the low sequence conservation. A fragment of the human telomerase RNA folds in vitro into an unusual pseudoknot structure, in which part of stem 2 is composed of a major-groove triple helix with uracils from the third strand forming Hoogsteen hydrogen bonds with adenines of the duplex [1]. Biochemical and genetic data showed that a pseudoknot with similar features is formed both in vitro and in vivo in the budding yeast Kluyveromyces lactis [2]. Here we present the results of modeling of telomerase RNA pseudoknot structures from various ciliate species, calculated with the computer program miniCarlo [3]. Most of the ciliate sequences analyzed are compatible with a similar type of a pseudoknot fold, supporting the notion that this element provides a conserved telomerase function.

References and Footnotes
  1. C.A. Theimer, C.A. Blois & J. Feigon, Mol. Cell 17, 671-82 (2005).
  2. K. Shefer, Y. Brown, V. Gorkovoy, T. Nussbaum, N.B. Ulyanov & Y. Tzfati, Mol. Cell. Biol., 27, 2130-43 (2007).
  3. V.B. Zhurkin, N.B. Ulyanov, A.A. Gorin & R.L. Jernigan, Proc. Nat. Acad. Sci. USA 88, 7046-50 (1991).

Nikolai B. Ulyanov*1
Kinneret Shefer2
Yehuda Tzfati2

1University of California,
San Francisco, CA 94158-2517, U.S.A.

2The Hebrew Univ. of Jerusalem,
Jerusalem, 91904, Israel

Phone*: 415-476-0707
Email: ulyanov@picasso.ucsf.edu