Abstract
Telomeres are the specialized structures at the end of linear chromosomes and terminate with a single-stranded 3′ overhang of the G-rich strand. The primary role of telomeres is to protect chromosome ends from recombination and fusion and from being recognized as broken DNA ends. This protective function can be achieved through association with specific telomere-binding proteins. Although proteins that bind single-stranded G-rich overhang regulate telomere length and telomerase activity in mammals and lower eukaryotes, equivalent factors have yet to be identified in plants. Here we have identified proteins capable of interacting with the G-rich single-stranded telomeric repeat from the Arabidopsis extracts by affinity chromatography. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry analysis indicates that the isolated protein is a chloroplast RNA-binding protein (and a truncated derivative). The truncated derivative, which we refer to as STEP1 (single-stranded telomere-binding protein 1), binds specifically the single-stranded G-rich plant telomeric DNA sequences but not double-stranded telomeric DNA. Unlike the chloroplast-localized full-length RNA-binding protein, STEP1 localizes exclusively to the nucleus, suggesting that it plays a role in plant telomere biogenesis. We also demonstrated that the specific binding of STEP1 to single-stranded telomeric DNA inhibits telomerase-mediated telomere extension. The evidence presented here suggests that STEP1 is a telomere-end binding protein that may contribute to telomere length regulation by capping the ends of chromosomes and thereby repressing telomerase activity in plants.
| Original language | English |
|---|---|
| Pages (from-to) | 12812-12818 |
| Number of pages | 7 |
| Journal | Journal of Biological Chemistry |
| Volume | 279 |
| Issue number | 13 |
| DOIs | |
| Publication status | Published - 2004 Mar 26 |
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All Science Journal Classification (ASJC) codes
- Biochemistry
- Molecular Biology
- Cell Biology
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Interaction of an Arabidopsis RNA-binding Protein with Plant Single-stranded Telomeric DNA Modulates Telomerase Activity. / Kwon, Chian; Chung, In Kwon.
In: Journal of Biological Chemistry, Vol. 279, No. 13, 26.03.2004, p. 12812-12818.Research output: Contribution to journal › Article
TY - JOUR
T1 - Interaction of an Arabidopsis RNA-binding Protein with Plant Single-stranded Telomeric DNA Modulates Telomerase Activity
AU - Kwon, Chian
AU - Chung, In Kwon
PY - 2004/3/26
Y1 - 2004/3/26
N2 - Telomeres are the specialized structures at the end of linear chromosomes and terminate with a single-stranded 3′ overhang of the G-rich strand. The primary role of telomeres is to protect chromosome ends from recombination and fusion and from being recognized as broken DNA ends. This protective function can be achieved through association with specific telomere-binding proteins. Although proteins that bind single-stranded G-rich overhang regulate telomere length and telomerase activity in mammals and lower eukaryotes, equivalent factors have yet to be identified in plants. Here we have identified proteins capable of interacting with the G-rich single-stranded telomeric repeat from the Arabidopsis extracts by affinity chromatography. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry analysis indicates that the isolated protein is a chloroplast RNA-binding protein (and a truncated derivative). The truncated derivative, which we refer to as STEP1 (single-stranded telomere-binding protein 1), binds specifically the single-stranded G-rich plant telomeric DNA sequences but not double-stranded telomeric DNA. Unlike the chloroplast-localized full-length RNA-binding protein, STEP1 localizes exclusively to the nucleus, suggesting that it plays a role in plant telomere biogenesis. We also demonstrated that the specific binding of STEP1 to single-stranded telomeric DNA inhibits telomerase-mediated telomere extension. The evidence presented here suggests that STEP1 is a telomere-end binding protein that may contribute to telomere length regulation by capping the ends of chromosomes and thereby repressing telomerase activity in plants.
AB - Telomeres are the specialized structures at the end of linear chromosomes and terminate with a single-stranded 3′ overhang of the G-rich strand. The primary role of telomeres is to protect chromosome ends from recombination and fusion and from being recognized as broken DNA ends. This protective function can be achieved through association with specific telomere-binding proteins. Although proteins that bind single-stranded G-rich overhang regulate telomere length and telomerase activity in mammals and lower eukaryotes, equivalent factors have yet to be identified in plants. Here we have identified proteins capable of interacting with the G-rich single-stranded telomeric repeat from the Arabidopsis extracts by affinity chromatography. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry analysis indicates that the isolated protein is a chloroplast RNA-binding protein (and a truncated derivative). The truncated derivative, which we refer to as STEP1 (single-stranded telomere-binding protein 1), binds specifically the single-stranded G-rich plant telomeric DNA sequences but not double-stranded telomeric DNA. Unlike the chloroplast-localized full-length RNA-binding protein, STEP1 localizes exclusively to the nucleus, suggesting that it plays a role in plant telomere biogenesis. We also demonstrated that the specific binding of STEP1 to single-stranded telomeric DNA inhibits telomerase-mediated telomere extension. The evidence presented here suggests that STEP1 is a telomere-end binding protein that may contribute to telomere length regulation by capping the ends of chromosomes and thereby repressing telomerase activity in plants.
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U2 - 10.1074/jbc.M312011200
DO - 10.1074/jbc.M312011200
M3 - Article
C2 - 14703514
AN - SCOPUS:1842424853
VL - 279
SP - 12812
EP - 12818
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 13
ER -