DNA repair enzyme that can remove a variety of covalent adducts from DNA through hydrolysis of a 3'-phosphodiester bond, giving rise to DNA with a free 3' phosphate. Catalyzes the hydrolysis of dead-end complexes between DNA and the topoisomerase I active site tyrosine residue. Hydrolyzes 3'-phosphoglycolates on protruding 3' ends on DNA double-strand breaks due to DNA damage by radiation and free radicals. Acts on blunt-ended double-strand DNA breaks and on single-stranded DNA. May have low 3'exonuclease activity and may be able to remove a single nucleoside from the 3'end of DNA and RNA molecules with 3'hydroxyl groups. Has no exonuclease activity towards DNA or RNA with a 3'phosphate (By similarity). Required for normal polarization of epidermal cells, correct subcellular location of the Crb complex to the apical lateral membrane, and for normal neuronal development during embryonic development. Expressed in the delaminating neuroblasts and a few ganglion mother cells in stage 11-14 embryonic central nervous system. Weak expression is seen in gonads at stage 16. Expressed both maternally and zygotically. Belongs to the tyrosyl-DNA phosphodiesterase family.