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EMBO J. 2009 Nov 18;28(22):3549-63. doi: 10.1038/emboj.2009.278. Epub 2009 Sep 24.

The MRT-1 nuclease is required for DNA crosslink repair and telomerase activity in vivo in Caenorhabditis elegans.

Author information

1
Department of Genetics, University of North Carolina, Chapel Hill, NC, USA.

Abstract

The telomerase reverse transcriptase adds de novo DNA repeats to chromosome termini. Here we define Caenorhabditis elegans MRT-1 as a novel factor required for telomerase-mediated telomere replication and the DNA-damage response. MRT-1 is composed of an N-terminal domain homologous to the second OB-fold of POT1 telomere-binding proteins and a C-terminal SNM1 family nuclease domain, which confer single-strand DNA-binding and processive 3'-to-5' exonuclease activity, respectively. Furthermore, telomerase activity in vivo depends on a functional MRT-1 OB-fold. We show that MRT-1 acts in the same telomere replication pathway as telomerase and the 9-1-1 DNA-damage response complex. MRT-1 is dispensable for DNA double-strand break repair, but functions with the 9-1-1 complex to promote DNA interstrand cross-link (ICL) repair. Our data reveal MRT-1 as a dual-domain protein required for telomerase function and ICL repair, which raises the possibility that telomeres and ICL lesions may share a common feature that plays a critical role in de novo telomere repeat addition.

PMID:
19779462
PMCID:
PMC2782091
DOI:
10.1038/emboj.2009.278
[Indexed for MEDLINE]
Free PMC Article

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