Recruitment of Oct4 protein to UV-damaged chromatin in embryonic stem cells.

Bártová,  Eva; Šustáčková, Gabriela; Stixová,  Lenka; Kozubek,  Stanislav; Legartová,  Soňa; Janečková,  Veronika

Recruitment of Oct4 protein to UV-damaged chromatin in embryonic stem cells.

Authors	BÁRTOVÁ Eva ŠUSTÁČKOVÁ Gabriela STIXOVÁ Lenka KOZUBEK Stanislav LEGARTOVÁ Soňa FOLTÁNKOVÁ Veronika
Year of publication	2011
Type	Article in Periodical
Magazine / Source	PloS ONE
Citation
Web	http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3229488/?tool=pubmed
Doi	http://dx.doi.org/10.1371/journal.pone.0027281
Keywords	DOUBLE-STRAND BREAKS; HISTONE H2AX PHOSPHORYLATION; DNA-DAMAGE; ES CELLS; HETEROCHROMATIN PROTEIN-1; GENE-EXPRESSION; POU DOMAIN; DIFFERENTIATION; REPAIR; NANOG
Description	BACKGROUND: Oct4 is a specific marker of embryonic stem cell (ESC) pluripotency. However, little is known regarding how Oct4 responds to DNA damage. Here, we investigated whether Oct4 recognizes damaged chromatin in mouse ESCs stably expressing GFP-Oct4. These experiments should contribute to the knowledge of how ESC genomic integrity is maintained, which is crucial for potential application of human ESCs in regenerative medicine. METHODOLOGY/PRINCIPAL FINDINGS: We used time-lapse confocal microscopy, microirradiation by UV laser (355 nm), induction of DNA lesions by specific agents, and GFP technology to study the Oct4 response to DNA damage. We found that Oct4 accumulates in UV-damaged regions immediately after irradiation in an adenosine triphosphate-dependent manner. Intriguingly, this event was not accompanied by pronounced Nanog and c-MYC recruitment to the UV-damaged sites. The accumulation of Oct4 to UV-damaged chromatin occurred simultaneously with H3K9 deacetylation and H2AX phosphorylation (gammaH2AX). Moreover, we observed an ESC-specific nuclear distribution of gammaH2AX after interference to cellular processes, including histone acetylation, transcription, and cell metabolism. Inhibition of histone deacetylases mostly prevented pronounced Oct4 accumulation at UV-irradiated chromatin. CONCLUSIONS/SIGNIFICANCE: Our studies demonstrate pluripotency-specific events that accompany DNA damage responses. Here, we discuss how ESCs might respond to DNA damage caused by genotoxic injury that might lead to unwanted genomic instability.