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  • Increased amounts and stability of telomeric repeat-containing RNA (TERRA) following DNA damage induced by etoposide.

Increased amounts and stability of telomeric repeat-containing RNA (TERRA) following DNA damage induced by etoposide.

PloS one (2019-11-23)
Bong-Kyeong Oh, Yoojung Choi, Jaeman Bae, Won Moo Lee, Jeong-Kyu Hoh, Joong Sub Choi
ABSTRACT

Telomeric repeat-containing RNAs (TERRAs) are long noncoding RNAs transcribed from subtelomeres toward telomeric repeat tracts, which have been implicated in telomere protection and heterochromatin formation. Genotoxic stress leads to upregulation of TERRAs. However, the mechanism of DNA damage-mediated TERRA induction remains elusive. Here, we treated HeLa cells with etoposide, a DNA double-strand break-generating agent, for various times and monitored the levels of TERRAs. Etoposide treatment led to a gradual time-dependent increase in TERRAs. Etoposide-mediated induction was evident in many TERRAs arising from various chromosome loci, including 20q and XpYp. Chromatin immunoprecipitation assays revealed no significant changes in the occupancy of RNA polymerase II at telomeres upon etoposide treatment. Interestingly, TERRAs arising from 20q, XpYp, 10q, and 13q degraded at slower rates in cells treated with etoposide, while degradation rates of TERRAs from many loci tested were nearly identical in both etoposide- and mock-treated cells. Telomere damage occurred from early time points of etoposide treatment, but telomere lengths and abundance of telomeric repeat-binding factor 2 (TRF2) at telomeres remained unchanged. In summary, etoposide treatment led to telomere damage and TERRA accumulation, but telomere lengths and TRF2-mediated telomere integrity were maintained. Etoposide-mediated TERRA accumulation could be attributed partly to RNA stabilization. These findings may provide insight into the post-transcriptional regulation of TERRAs in response to DNA damage.

MATERIALS
Product Number
Brand
Product Description

Roche
DIG DNA Labeling and Detection Kit
Sigma-Aldrich
Anti-RNA polymerase II Antibody, clone CTD4H8, clone CTD4H8, Upstate®, from mouse
Sigma-Aldrich
Normal Mouse IgG, Normal Mouse IgG Polyclonal Antibody control validated for use in Immunoprecipitation & Western Blotting.