Component of the PeBoW complex, which is required for maturation of 28S and 5.8S ribosomal RNAs and formation of the 60S ribosome (By similarity). Required for neural crest migration and eye development. Component of the PeBoW complex, composed of bop1, pes1 and wdr12. The complex is held together by bop1, which interacts with pes1 via its N-terminal domain and with wdr12 via a high-affinity interaction between the seven-bladed beta-propeller domains of the 2 proteins. The PeBoW complex associates with the 66S pre-ribosome. Maternally expressed. Strongly expressed in the anterior neural plate at stage 18. Expressed in the migrating cranial neural crest and the developing eye at stage 23. Also expressed in the midbrain-hindbrain boundary, migrating neural crest cells and the periocular mesenchyme at stages 26-31. Expression appears to require Wnt-4 activity. Belongs to the pescadillo family.