Component of the NOP7 complex, which is required for maturation of the 25S and 5.8S ribosomal RNAs and formation of the 60S ribosome. Component of the NOP7 complex, composed of ERB1, NOP7 and YTM1. The complex is held together by ERB1, which interacts with NOP7 via its N-terminal domain and with YTM1 via a high-affinity interaction between the seven-bladed beta-propeller domains of the 2 proteins. The NOP7 complex associates with the 66S pre-ribosome (PubMed:26476442, PubMed:26657628). Interacts (via UBL domain) with MDN1 (via VWFA/MIDAS domain) (By similarity). Belongs to the WD repeat WDR12/YTM1 family.