Single-strand DNA-binding protein SSB1 facilitates TERT recruitment to telomeres and maintains telomere G-overhangs.

Abstract:

:Proliferating mammalian stem and cancer cells express telomerase [telomerase reverse transcriptase (TERT)] in an effort to extend chromosomal G-overhangs and maintain telomere ends. Telomerase-expressing cells also have higher levels of the single-stranded DNA-binding protein SSB1, which has a critical role in DNA double-strand break (DSB) repair. Here, we report that SSB1 binds specifically to G-strand telomeric DNA in vitro and associates with telomeres in vivo. SSB1 interacts with the TERT catalytic subunit and regulates its interaction with telomeres. Deletion of SSB1 reduces TERT interaction with telomeres and leads to G-overhang loss. Although SSB1 is recruited to DSB sites, we found no corresponding change in TERT levels at these sites, implying that SSB1-TERT interaction relies upon a specific chromatin structure or context. Our findings offer an explanation for how telomerase is recruited to telomeres to facilitate G-strand DNA extension, a critical step in maintaining telomere ends and cell viability in all cancer cells. Cancer Res; 75(5); 858-69. ©2015 AACR.

journal_name

Cancer Res

journal_title

Cancer research

authors

Pandita RK,Chow TT,Udayakumar D,Bain AL,Cubeddu L,Hunt CR,Shi W,Horikoshi N,Zhao Y,Wright WE,Khanna KK,Shay JW,Pandita TK

doi

10.1158/0008-5472.CAN-14-2289

subject

Has Abstract

pub_date

2015-03-01 00:00:00

pages

858-69

issue

5

eissn

0008-5472

issn

1538-7445

pii

0008-5472.CAN-14-2289

journal_volume

75

pub_type

杂志文章