Abstract
Poly(ADP-ribosyl)ation regulates chromatin structure and transcription driving epigenetic events. In particular, Parp1 is able to directly influence DNA methylation patterns controlling transcription and activity of Dnmt1. Here, we show that ADP-ribose polymer levels and Parp1 expression are noticeably high in mouse primordial germ cells (PGCs) when the bulk of DNA demethylation occurs during germline epigenetic reprogramming in the embryo. Notably, Parp1 activity is stimulated in PGCs even before its participation in the DNA damage response associated with active DNA demethylation. We demonstrate that PARP inhibition impairs both genome-wide and locus-specific DNA methylation erasure in PGCs. Moreover, we evidence that impairment of PARP activity causes a significant reduction of expression of the gene coding for Tet1 hydroxylases involved in active DNA demethylation. Taken together these results demonstrate new and adjuvant roles of poly(ADP-ribosyl)ation during germline DNA demethylation and suggest its possible more general involvement in genome reprogramming.
Highlights
Epigenetics plays a crucial role in regulating cell lineage determination through the action of DNA methylation and chromatin remodeling machineries
QRT-PCR evidenced an up-regulation of Parp1 transcript at E11.5 (Figure 1B) and further analysis of Parp1 protein in single cells performed by confocal microscopy confirmed a mild increase (Figure 1C, D)
Since Parp1 can be activated by interaction with protein partners such as Parp3 and CCCTC-binding factor (Ctcf) [38,40], we evaluated the expression of these proteins
Summary
Epigenetics plays a crucial role in regulating cell lineage determination through the action of DNA methylation and chromatin remodeling machineries. Overall chromatin changes mostly occur after PGC arrival into the gonadal ridges at the embryonic day 11.5 (E11.5) [6,9,10] and they involve histone modifications and a well-characterized widespread DNA demethylation [4,5,6]. Such events are essential for generation of totipotent gametes with proper sex-specific imprints and for erasure of epimutations which may lead to inheritance of disease phenotypes [1,11]. Activation-induced (cytidine) deaminase (Aid) actively participates in PGC DNA demethylation [14] and a strong induction of ten-eleven translocation 1 (Tet1) gene, encoding one of the enzymes that convert 5meC to 5hmeC [15], has been shown in E11.5 PGCs [11,12]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
