Next Meeting : September 19th 2013 – IAB

Our next meeting will be on Thursday, September 19th 2013 10am at the IAB (access).

The speakers will be :
Seminar by Dr. Sophie Polo (Epigenetics and Cell Fate, Paris)
Chromatin licensing for transcription restart after DNA damage: another “Sleeping Beauty” story

Short talk: Dr. Kiran Padmanabhan (IAB, Grenoble)
Transcriptional regulation of the mammalian circadian clock

Short talk: Dr. Pietro Spinelli (EMBL, Grenoble)
The conserved germline RNA helicase Vasa assembles an ATP-dependent piRNA biogenesis complex

Coffee break and lunch will be provided by Active Motif, who is sponsoring our meetings.

More information
Seminar by Dr. Sophie Polo (Epigenetics and Cell Fate, Paris)
Chromatin licensing for transcription restart after DNA damage: another “Sleeping Beauty” story
To prevent the deleterious effects of DNA damage that constantly challenge genome integrity, cells activate signaling and repair mechanisms and concomitantly regulate other DNA metabolic activities among which transcription. Significant advances have been made in understanding how transcription is inhibited in response to genotoxic stress. By contrast, the mechanisms of transcription restart, although essential for a complete recovery from DNA damage, remain poorly characterized. The growing importance of chromatin in regulating gene expression and integrating damage signals prompted us to explore whether and how transcription recovery might be coupled to chromatin restoration after DNA repair.
For this, we have examined how histone chaperones and specific histone variants regulate transcription restart in response to DNA damage in human cells. By combining local UVC irradiation with covalent pulse-labeling of histone proteins to track newly synthesized histones in vivo, we have analyzed the dynamics of the three major types of histone H3 variants at damage sites. This approach has enabled us to uncover a novel histone deposition pathway that promotes restoration of chromatin structure and function in response to genotoxic stress. We have identified the responsible histone chaperone and its mode of targeting to DNA damage sites. Furthermore, we have delineated its functional importance in the earliest stages of the DNA damage response for later reactivation of transcription once repair is complete.
We propose that chromatin bookmarking by histone deposition in response to DNA damage is a necessary step that licenses chromatin for transcription recovery after repair.