Inhibits the poly(ADP-ribosyl)ation activity of PARP1 and the degradation of PARP1 by CASP3 following genotoxic stress. Binds to double-stranded RNA or DNA without sequence specificity. Involved in development of the eye and of primordial germ cells. Interacts with PARP1 (via catalytic domain). Localizes predominantly in the nucleolus with minor punctate signals in the nucleoplasm. A 90 degree bend between Pumilio repeats 3 and 4 gives rise to a L-shaped protein.