Chromosome stability is crucial for the faithful passage of genetic information at each cell division. Telomeres are structures at chromosomal termini that are essential for chromosome stability. All telomeric DNA contains simple, G/C-rich, repeated sequences in which the G and C residues are segregated to opposite strands of the duplex. The G-rich strand of all telomeres examined extends beyond the duplex at the molecular terminus of the telomere. In vitro, all telomeric G-rich strands tested can self-associate by non-Watson-Crick (G-G and G-T) base pairing. Taken together, these data suggest that the G-strand overhang forms a self-associated structure in vivo and that this structure is intimately involved in telomere function. The goal of this project is to understand how telomeres confer stability to chromosomes and, more specifically, what the role(s) of the unique G- strand DNA structure is (are) in accomplishing this.
The specific aims are: 1) to determine the molecular details of the G-strand structure, 2) to ascertain the biological function of the telomeric G-strand structure using in vitro and in vivo assays and to determine if non-Watson-Crick base paired structures can form in a Watson-Crick Environment, 3) to characterize an activity we have identified that binds specifically to the G-strand structure, 4) to produce monoclonal antibodies that react with the G-strand structure and 5) to explore telomere location and dynamics in fixed and living cells by fluorescence and electron microscopy.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
First Independent Research Support & Transition (FIRST) Awards (R29)
Project #
5R29GM041023-03
Application #
3467351
Study Section
Molecular Biology Study Section (MBY)
Project Start
1989-07-01
Project End
1994-06-30
Budget Start
1991-07-01
Budget End
1992-06-30
Support Year
3
Fiscal Year
1991
Total Cost
Indirect Cost
Name
Iowa State University
Department
Type
Schools of Arts and Sciences
DUNS #
City
Ames
State
IA
Country
United States
Zip Code
50011
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Shaiu, W L; Larson, D D; Vesenka, J et al. (1993) Atomic force microscopy of oriented linear DNA molecules labeled with 5nm gold spheres. Nucleic Acids Res 21:99-103
Henderson, E (1992) Imaging and nanodissection of individual supercoiled plasmids by atomic force microscopy. Nucleic Acids Res 20:445-7
Henderson, E (1992) Atomic force microscopy of conventional and unconventional nucleic acid structures. J Microsc 167:77-84
Hardin, C C; Henderson, E; Watson, T et al. (1991) Monovalent cation induced structural transitions in telomeric DNAs: G-DNA folding intermediates. Biochemistry 30:4460-72