Yoo Hyun Hee, Kwon Chian, Lee Myeong Min, Chung In Kwon
Department of Biology and Molecular Aging Research Center, Yonsei University, Seoul 120-749, Korea.
Plant J. 2007 Feb;49(3):442-51. doi: 10.1111/j.1365-313X.2006.02974.x. Epub 2007 Jan 1.
Telomere homeostasis, a process that is essential for the maintenance of chromosome integrity, is regulated by telomerase and a collection of associated proteins. By mass spectrometry we have identified a new telomeric protein encoded by the AtWHY1 (Arabidopsis thaliana Whirly 1) gene in Arabidopsis. AtWHY1 specifically binds the single-stranded plant telomeric DNA sequences, but not double-stranded telomeric DNA. To gain insights into the function of AtWHY1 in telomere biogenesis, we have identified two Arabidopsis lines harboring T-DNA insertions in AtWHY1. These lines exhibit neither growth nor developmental defects. However, AtWHY1-deficient plants show a steady increase in the length of telomere tracts over generations. This telomere elongation is correlated with a significant increase in telomerase activity. On the contrary, transgenic plants expressing AtWHY1 show a decreased telomerase activity and shortened telomeres. The evidence presented here indicates that AtWHY1 is a new family of telomere end-binding proteins that plays a role in regulating telomere-length homeostasis in Arabidopsis.
端粒稳态是维持染色体完整性所必需的过程，由端粒酶和一系列相关蛋白调控。通过质谱分析，我们在拟南芥中鉴定出一种由AtWHY1（拟南芥Whirly 1）基因编码的新型端粒蛋白。AtWHY1特异性结合单链植物端粒DNA序列，但不结合双链端粒DNA。为深入了解AtWHY1在端粒生物合成中的功能，我们鉴定出两个在AtWHY1中存在T-DNA插入的拟南芥株系。这些株系既未表现出生长缺陷也未出现发育缺陷。然而，缺乏AtWHY1的植株端粒序列长度在多代中稳步增加。这种端粒延长与端粒酶活性的显著增加相关。相反，表达AtWHY1的转基因植株端粒酶活性降低且端粒缩短。此处提供的证据表明，AtWHY1是端粒末端结合蛋白的一个新家族，在调控拟南芥端粒长度稳态中发挥作用。
