Poly ADP-ribose polymerase-1: Beyond transcription and towards differentiation.

Gene regulation mediates the processes of cellular development and differentiation leading to the origin of different cell types each having their own signature gene expression profile. However, the compact chromatin structure and the timely recruitment of molecules involved in various signaling pathways are of prime importance for temporal and spatial gene regulation that eventually contribute towards cell type and specificity. Poly (ADP-ribose) polymerase-1 (PARP-1), a 116-kDa nuclear multitasking protein is involved in modulation of chromatin condensation leading to altered gene expression. In response to activation signals, it adds ADP-ribose units to various target proteins including itself, thus regulating various key cellular processes like DNA repair, cell death, transcription, mRNA splicing etc. This review provides insights into the role of PARP-1 in gene regulation, cell differentiation and multicellular morphogenesis. In addition, the review also explores involvement of PARP-1 in immune cells development and therapeutic possibilities to treat various human diseases.