Inhibits the poly(ADP-ribosyl)ation activity of PARP1 and the degradation of PARP1 by CASP3 following genotoxic stress (PubMed:21266351). Binds to double-stranded RNA or DNA without sequence specificity (PubMed:25512524). Involved in development of the eye and of primordial germ cells (By similarity). Interacts with PARP1 (via catalytic domain). Localizes predominantly in the nucleolus with minor punctate signals in the nucleoplasm. Widely expressed. The HA-8 region can be cleaved and exposed at the cell surface where it plays a role as a minor histocompatibility HLA-A*0201-restricted antigen. A 90 degree bend between Pumilio repeats 3 and 4 gives rise to a L-shaped protein. The following alleles of HA-8 are known: HA-8R, HA-8P, HA-8PL, of which only HA-8R leads to specific cytotoxic T lymphocyte (CTL) recognition. The lack of CTL recognition of cells expressing HA-8P may be due to impaired transport associated with antigen processing. The sequence shown is that of HA-8R. Truncated N-terminus.