The p23 molecular chaperone promotes functional telomerase complexes through DNA dissociation.

Oyetunji A Toogun, Will Zeiger, Brian C Freeman

Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, 601 South Goodwin Avenue, Urbana, IL 61801, USA.

Proceedings of the National Academy of Sciences of the United States of America 2007 Apr 3

filter terms:

Telomeres are the composite of short DNA element tandem arrays and heterotypic protein components that protect and maintain chromosomal termini. As proper telomere maintenance requires a multitude of DNA extension events, it is important to understand the factors that modulate telomerase DNA association. Here, we show that the endogenous levels of the yeast p23 molecular chaperone Sba1p are required for telomere length maintenance and that Sba1p can modulate telomerase DNA binding and extension activities in vitro. Notably, telomere occupancy by telomerase and the extension rate of a shortened telomere fluctuated with changing Sba1 protein levels in vivo. In addition, we found that Sba1p displayed a cell cycle-dependent telomere interaction that paralleled telomerase binding; telomere association by Sba1p depended on its inherent chaperone activity. Taken together, our results support a model in which Sba1p modulates telomerase DNA binding activity for optimal function in vitro and in vivo.

Citation

Oyetunji A Toogun, Will Zeiger, Brian C Freeman. The p23 molecular chaperone promotes functional telomerase complexes through DNA dissociation. Proceedings of the National Academy of Sciences of the United States of America. 2007 Apr 3;104(14):5765-70