Abstract
The BLM helicase associates with the telomere structural proteins TRF1 and TRF2 in immortalized cells using the alternative lengthening of telomere (ALT) pathways. This work focuses on identifying protein partners of BLM in cells using ALT. Mass spectrometry and immunoprecipitation techniques have identified three proteins that bind directly to BLM and TRF2 in ALT cells: telomerase-associated protein 1 (TEP1), heat shock protein 90 (HSP90), and topoisomerase IIα (TOPOIIα). BLM predominantly co-localizes with these proteins in foci actively synthesizing DNA during late S and G2/M phases of the cell cycle when ALT is thought to occur. Immunoprecipitation studies also indicate that only HSP90 and TOPOIIα are components of a specific complex containing BLM, TRF1, and TRF2 but that this complex does not include TEP1. TEP1, TOPOIIα, and HSP90 interact directly with BLM in vitro and modulate its helicase activity on telomere-like DNA substrates but not on non-telomeric substrates. Initial studies suggest that knockdown of BLM in ALT cells reduces average telomere length but does not do so in cells using telomerase.
| Original language | English |
|---|---|
| Pages (from-to) | 14966-14977 |
| Number of pages | 12 |
| Journal | Journal of Biological Chemistry |
| Volume | 284 |
| Issue number | 22 |
| DOIs | |
| State | Published - May 29 2009 |
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ASJC Scopus subject areas
- Biochemistry
- Cell Biology
- Molecular Biology
Cite this
Telomerase-associated protein 1, HSP90, and topoisomerase IIα associate directly with the BLM helicase in immortalized cells using ALT and modulate its helicase activity using telomeric DNA substrates. / Bhattacharyya, Saumitri; Keirsey, Jeremy; Russell, Beatriz; Kavecansky, Jurai; Lillard-Wetherell, Kate; Tahmaseb, Kambiz; Turchi, John; Groden, Joanna.
In: Journal of Biological Chemistry, Vol. 284, No. 22, 29.05.2009, p. 14966-14977.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Telomerase-associated protein 1, HSP90, and topoisomerase IIα associate directly with the BLM helicase in immortalized cells using ALT and modulate its helicase activity using telomeric DNA substrates
AU - Bhattacharyya, Saumitri
AU - Keirsey, Jeremy
AU - Russell, Beatriz
AU - Kavecansky, Jurai
AU - Lillard-Wetherell, Kate
AU - Tahmaseb, Kambiz
AU - Turchi, John
AU - Groden, Joanna
PY - 2009/5/29
Y1 - 2009/5/29
N2 - The BLM helicase associates with the telomere structural proteins TRF1 and TRF2 in immortalized cells using the alternative lengthening of telomere (ALT) pathways. This work focuses on identifying protein partners of BLM in cells using ALT. Mass spectrometry and immunoprecipitation techniques have identified three proteins that bind directly to BLM and TRF2 in ALT cells: telomerase-associated protein 1 (TEP1), heat shock protein 90 (HSP90), and topoisomerase IIα (TOPOIIα). BLM predominantly co-localizes with these proteins in foci actively synthesizing DNA during late S and G2/M phases of the cell cycle when ALT is thought to occur. Immunoprecipitation studies also indicate that only HSP90 and TOPOIIα are components of a specific complex containing BLM, TRF1, and TRF2 but that this complex does not include TEP1. TEP1, TOPOIIα, and HSP90 interact directly with BLM in vitro and modulate its helicase activity on telomere-like DNA substrates but not on non-telomeric substrates. Initial studies suggest that knockdown of BLM in ALT cells reduces average telomere length but does not do so in cells using telomerase.
AB - The BLM helicase associates with the telomere structural proteins TRF1 and TRF2 in immortalized cells using the alternative lengthening of telomere (ALT) pathways. This work focuses on identifying protein partners of BLM in cells using ALT. Mass spectrometry and immunoprecipitation techniques have identified three proteins that bind directly to BLM and TRF2 in ALT cells: telomerase-associated protein 1 (TEP1), heat shock protein 90 (HSP90), and topoisomerase IIα (TOPOIIα). BLM predominantly co-localizes with these proteins in foci actively synthesizing DNA during late S and G2/M phases of the cell cycle when ALT is thought to occur. Immunoprecipitation studies also indicate that only HSP90 and TOPOIIα are components of a specific complex containing BLM, TRF1, and TRF2 but that this complex does not include TEP1. TEP1, TOPOIIα, and HSP90 interact directly with BLM in vitro and modulate its helicase activity on telomere-like DNA substrates but not on non-telomeric substrates. Initial studies suggest that knockdown of BLM in ALT cells reduces average telomere length but does not do so in cells using telomerase.
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U2 - 10.1074/jbc.M900195200
DO - 10.1074/jbc.M900195200
M3 - Article
VL - 284
SP - 14966
EP - 14977
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 22
ER -