Dynamic Interactions of Arabidopsis TEN1: Stabilizing Telomeres in Response to Heat Stress.
Telomeres are the essential nucleoprotein structures that provide a physical cap for the ends of linear chromosomes. The highly conserved CST (CTC1/STN1/TEN1) protein complex facilitates telomeric DNA replication and promotes telomere stability. Here we report three unexpected properties ofArabidopsis thalianaTEN1 that indicate it possesses functions distinct from other previously characterized telomere proteins. First, we show that telomeres inten1mutants are highly sensitive to thermal stress. Heat shock causes abrupt and dramatic loss of telomeric DNA inten1plants, likely via deletional recombination. Second, we show that AtTEN1 has the properties of a heat-shock induced molecular chaperone. At elevated temperature, AtTEN1 rapidly assembles into high molecular weight homo-oligomeric complexes that efficiently suppress heat-induced aggregation of model protein substrates in vitro. Finally, we report that AtTEN1 specifically protects CTC1 from heat-induced aggregation in vitro, and from heat-induced protein degradation and loss of telomere association in vivo. Collectively, these observations define Arabidopsis TEN1 as a highly dynamic protein that works in concert with CTC1 to preserve telomere integrity in response to environmental stress.
Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843-2128.
Jung Ro
JR
Lee
Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843-2128.
Xiaoyuan
http://orcid.org/0000-0002-5030-9810
X
Xie
Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843-2128.
Kailu
K
Yang
Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843-2128.
Junjie
J
Zhang
Division of Applied Life Sciences (BK21) and PMBBRC, Gyeongsang National University, Jinju 52828, Republic of Korea.
Sang Yeol
SY
Lee
Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843-2128 dshippen@tamu.edu.
Dorothy E
DE
Shippen