The contribution of PARP1, PARP2 and poly(ADP-ribosyl)ation to base excision repair in the nucleosomal context

Abstract

The regulation of repair processes including base excision repair (BER) in the presence of DNA damage is implemented by a cellular signal: poly(ADP-ribosyl)ation (PARylation), which is catalysed by PARP1 and PARP2. Despite ample studies, it is far from clear how BER is regulated by PARPs and how the roles are distributed between the PARPs. Here, we investigated the effects of PARP1, PARP2 and PARylation on activities of the main BER enzymes (APE1, DNA polymerase β [Polβ] and DNA ligase IIIα [LigIIIα]) in combination with BER scaffold protein XRCC1 in the nucleosomal context. We constructed nucleosome core particles with midward- or outward-oriented damage. It was concluded that in most cases, the presence of PARP1 leads to the suppression of the activities of APE1, Polβ and to a lesser extent LigIIIα. PARylation by PARP1 attenuated this effect to various degrees depending on the enzyme. PARP2 had an influence predominantly on the last stage of BER: DNA sealing. Nonetheless, PARylation by PARP2 led to Polβ inhibition and to significant stimulation of LigIIIα activities in a NAD+-dependent manner. On the basis of the obtained and literature data, we suggest a hypothetical model of the contribution of PARP1 and PARP2 to BER.

Dual function of HPF1 in the modulation of PARP1 and PARP2 activities

“…PARP2 can therefore play a key role in the subsequent chromatin decompaction necessary for the recruitment of DNA repair factors to the damage sites. This idea is supported by the data of Bilokapic’s work on the ability of the PARP2-HPF1 complex to retain two nucleosomes located near the DSB 29 , consistent with observations that PARP2 persists longer than PARP1 at DNA damage sites 16 , 18 , 44 .…”

“…Roles of PARP1 and PARP2 in base excision repair and single-strand break repair were intensively studied 12 – 14 . Overlapping functions of PARP1 and PARP2 in regulation of these processes were shown by using model DNA duplexes 15 , 16 as well as nucleosomes 17 , 18 . PARP2 is comparable with or even more efficient than PARP1 in binding DNA breaks, but has a lower affinity for intact DNA and AP sites 8 , 16 , 19 .…”

“…PARP2 is comparable with or even more efficient than PARP1 in binding DNA breaks, but has a lower affinity for intact DNA and AP sites 8 , 16 , 19 . Difference in the affinities of PARP1 and PARP2 for various DNA structures in the nucleosome context was lately revealed 18 . PARP2 synthesizes shorter PAR chains than PARP1 does and also inhibits PARP1-catalyzed PAR synthesis via hetero-oligomerization of the two PARPs 8 , 10 .…”

Functional Roles of PARP2 in Assembling Protein–Protein Complexes Involved in Base Excision DNA Repair

“…The requirement for PARP2 in BER demonstrated in vivo has been proposed to be mediated by its interaction with PARP1 [ 13 ]. Despite the accumulated numerous data on PARP2 interaction with BER DNA intermediates and functions of its structural domains [ 8 , 15 , 17 , 18 , 19 , 21 , 22 , 33 ], the exact role of PARP2 in BER remains obscure. PARP2 differs substantially from PARP1 in the modular architecture composed of an N-terminal region (NTR), a central WGR domain, and a C-terminal catalytic (CAT) domain [ 8 ].…”

Human PARP1 Facilitates Transcription through a Nucleosome and Histone Displacement by Pol II In Vitro

“…Poly(ADP-ribosyl)ation (PARylation) is an essential covalent protein modification introduced by various poly-ADP-ribose polymerases (PARPs), a family of enzymes that transfer adenosine diphosphate ribose (ADP-ribose) from NAD+ onto a variety of proteins [1,2]. PARP1 is an abundant multi-domain protein, localized in cell nuclei that is responsible for at least 85% of cellular PARP activity [3].…”