Skip to Content
Merck
  • Nucleolar Reorganization Upon Site-Specific Double-Strand Break Induction.

Nucleolar Reorganization Upon Site-Specific Double-Strand Break Induction.

The journal of histochemistry and cytochemistry : official journal of the Histochemistry Society (2016-09-30)
Michal Franek, Alena Kovaříková, Eva Bártová, Stanislav Kozubek
ABSTRACT

DNA damage response (DDR) in ribosomal genes and mechanisms of DNA repair in embryonic stem cells (ESCs) are less explored nuclear events. DDR in ESCs should be unique due to their high proliferation rate, expression of pluripotency factors, and specific chromatin signature. Given short population doubling time and fast progress through G1 phase, ESCs require a sustained production of rRNA, which leads to the formation of large and prominent nucleoli. Although transcription of rRNA in the nucleolus is relatively well understood, little is known about DDR in this nuclear compartment. Here, we directed formation of double-strand breaks in rRNA genes with I- PpoI endonuclease, and we studied nucleolar morphology, DDR, and chromatin modifications. We observed a pronounced formation of I- PpoI-induced nucleolar caps, positive on BRCA1, NBS1, MDC1, γH2AX, and UBF1 proteins. We showed interaction of nucleolar protein TCOF1 with HDAC1 and TCOF1 with CARM1 after DNA injury. Moreover, H3R17me2a modification mediated by CARM1 was found in I- PpoI-induced nucleolar caps. Finally, we report that heterochromatin protein 1 is not involved in DNA repair of nucleolar caps.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Anti-NBS1 (Nibrin) antibody produced in rabbit, affinity isolated antibody, buffered aqueous solution
Sigma-Aldrich
Monoclonal Anti-BRCA1 antibody produced in mouse
Sigma-Aldrich
Anti-acetyl-Histone H3 (Lys9) Antibody, Upstate®, from rabbit
Sigma-Aldrich
Anti-HDAC1 Antibody, Upstate®, from rabbit