Detection of quadruplex DNA structures in human telomeres by using a fluorescence probe BMVC molecule

BIOL 109

Ta-Chau Chang, tcchang@po.iams.sinica.edu.tw1, Cheng-Chung Chang1, Jen-Fei Chu1, Fu-Jen Kao2, and Pei-Jen Lou3. (1) Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, No.1, Roosevelt Rd., Sec. 4, Taipei, 10617, Taiwan, (2) Institute of Biophotonics Engineering, National Yang-Ming University, Taipei, 11221, Taiwan, (3) Department of Otolaryngology, National Taiwan University Hospital, Taipei, Taiwan
Single-stranded telomeric DNA tends to form a four base-paired planer structure termed G-quadruplex. This structure was easily formed in vitro in the presence of monovalent cations. However, the existence of this structure in native human telomeres is still in debate. Here we address this important question through the distinctive properties of 3,6-bis(1-methyl-4-vinylpyridinium)carbazole diiodide (BMVC) upon binding to various DNA structures. Although the fluorescence of BMVC increases significantly in the presence of DNA, BMVC has high sensitivity and binding preference to quadruplex d(T2AG3)4 over duplex DNA. Moreover, we have applied two-photon excitation (TPE) fluorescence lifetime imaging microscopy (FLIM) to measure the fluorescence lifetime of the BMVC molecule upon interaction with various DNA structures. The distinction in lifetime measured with sub-micron spatial resolution in TPE-FLIM provides a powerful approach not only to verify the existence of the G-quadruplex structure in human telomeres, but also to map its localizations in metaphase chromosomes.
 

Chemistry and Metabolism
4:30 PM-6:30 PM, Tuesday, 12 September 2006 Moscone Center -- Hall D, Poster

Division of Biological Chemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006