Effects of
Lead and Selenium on Telomere Binding Protein Rap1p, Telomerase and Telomeric
DNA in Saccharomyces cerevisiae
CUI Qing-Hua, TANG Chia-Chun*,
HUANG You-Guo1
( Research Center for Eco-Environmental Sciences, the Chinese Academy
of Sciences, Beijing 100085, China；1National Laboratory of
Biomacromolecules, Institute of Biophysics, the Chinese Academy of Sciences,
Beijing 100101,
China )
Abstract The effects
on S.cerevisiae telomere binding protein Rap1p, telomerase and telomeric
DNA by the lead (Pb), the selenium (Se) and Pb + Se were tested respectively in
this study. Compared with the control S.cerevisiae after 100 gene
rations, the mean telomere length shortened, Rap1p concentration was
significantly lower and the secondary structure of Rap1p was disturbed, the
telomerase activity was reduced in Pb treated cells. In Se treated cells,
telomere length was significantly longer, and telomerase activity expressed
higher. The concentration and secondary structure of Rap1p were similar to that
of the control. Further more, the viability of Pb treated cells were
significantly reduced while cells undergone other three treatments were similar
and normal. These results suggest that Pb could damage Rap1p, reduce telomerase
activity, resulting in the telomer length shortening and cell death. On the
other hand, Se could protect and repair the damage in Rap1p and telomere caused
by Pb to some extent.
Key words Saccharomyces cerevisiae;Pb and
Se;telomere length; telomerase;telomere binding protein Rap1p;
*Corresponding author: Tel,
86-10-62849129; Fax, 86-10-62923563; e-mail:[email protected]