DNA sequence. The complexes also differed in their 
protein-DNA contacts and in the rate of DNA ex- 
change. The patterns of protein-DNA interaction 
suggested a model in which the protein can bind 
either to the two repeats at the 3' end of the DNA 
or to two internal repeats; only in the latter case 
can it make an additional set of contacts to form 
the more stable complex. Native telomeric chroma- 
' tin isolated from Oxytricha contains both types of 
complexes. The reconstituted monomeric com- 
plexes associated to give a high-molecular-weight 
PUBLICATIONS 
form with an altered chemical footprint. Such inter- 
actions are proposed to mediate the association of 
chromosome ends in vivo. 
Dr. Cech is also American Cancer Society Re- 
search Professor of Chemistry and Biochemistry 
and of Molecular, Cellular, and Developmental 
Biology at the University of Colorado at Boulder 
and Professor of Biochemistry, Biophysics, and Ge- 
netics at the University of Colorado Health Sciences 
Center. 
Books and Chapters of Books 
Cech, T.R. , editor. 19S9 . Molecular Biology ofRNA. New York: Liss, 392 pp. 
Articles 
Cech, TR. 1988. Conserved sequences and structures of group I introns: building an active site for RNA catal- 
ysis. Gene 73:259-271. 
Cech, T.R. 1988. Ribozymes and their medical implications./AMA 260:3030-3034. 
Cech, TR. 1989. Ribozyme self-replication? TV^fwre 339:507-508. 
Cech, T.R. 1989. RNA as an enzyme. Biochem Int 18:7-14. 
Latham, J.A., and Cech, T.R. 1989. Defining the inside and outside of a catalytic RNA molecule. Science 
245:276-282. 
McSwiggen, J.A., and Cech, T.R. 1989. Stereochemistry of RNA cleavage by the Tetrahymena ribozyme and ev- 
idence that the chemical step is not rate-limiting. Science 244:679-683. 
Morin, G.B., and Cech, T.R. 1988. Telomeric repeats of Tetrahymena malaccensis mitochondrial DNA: a 
multimodal distribution that fluctuates erratically during growth. Mol Cell Biol 8:4450-4458. 
Price, CM., and Cech, T.R. 1989. Properties of the telomeric DNA-binding protein from Oxytricha nova. Bio- 
chemistry 28:769-774. 
Price, J.V, and Cech, T.R. 1988. Determinants of the 3' splice site for self-splicing of the Tetrahymena pre- 
rRNA. Genes Dev 2:1439-1447. 
Raghuraman, M.K., Dunn, C.J., Hicke, B.J., and Cech, TR. 1989. Oxytricha telomeric nucleoprotein com- 
plexes reconstituted with synthetic DNA. Nucleic Acids Res 17:4235-4253. 
Woodson, S.A., and Cech, T.R. 1989. Reverse self-splicing of the Tetrahymena group I intron: implication for 
the directionality of splicing and for intron transposition. Cell 57:335-345. 
Zaug, A.J. , Grosshans, C.A., and Cech, T.R. 1988. Sequence-specific endoribonuclease activity of the Tetrahy- 
mena ribozyme: enhanced cleavage of certain oligonucleotide substrates that form mismatched ribozyme- 
substrate complexes. Biochemistry 27:8924-8931. 
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