Co‐localization of poly(ADPR)polymerase 1 (PARP‐1) poly(ADPR)polymerase 2 (PARP‐2) and related proteins in rat testis nuclear matrix defined by chemical cross‐linking

Poly(ADPR)polymerase 1 and 2 (PARP-1, PARP-2) are nuclear enzymes which function is based on specific interactions with DNA and nuclear proteins. PARPs targets include proteins involved in DNA replication, repair, and transcription and their function can be modulated either by protein-protein interaction with native PARP-1 and by non-covalent interaction with poly(ADP-ribose) (pADPR) linked to the auto-modified PARP-1. Moreover, the association of pADPR and PARP-1 with the nuclear matrix (NM) has been reported, based on the poly(ADP-ribosyl)ation of nuclear matrix proteins (NMPs). In the present article, by the use of DNA and protein cross-linking reactions, by cis-diamminedichloroplatinum II (cDDP) and sodium tetrathionate (NaTT) respectively, we present more evidences about the association of PARP-1, PARP-2, and PARPs related proteins with the NM. Our findings confirmed that NM could be seen as a fraction greatly enriched in transcription factors (i.e., C/EBP-beta) and enzymes (DNA Topo II, DNA PK) that co-localize with PARP-1 and -2 at the matrix associated regions (MARs) of chromatin. Moreover, pADPR contributes to PARP-1 localization at the NM, showing that PARP(s) activity co-operates to the functions of this nuclear fraction.