Involved in pre-rRNA processing. Required for maintaining steady-state levels of 40S ribosomal subunit. Required for the initial processing of pre-rRNA at the A0 to A2 sites, leading to the processing of the 23S pre-rRNA intermediate to the 18S rRNA. Interacts with NOP1. Binds to the 35S pre-rRNA and the U3 snoRNA. Present with 2220 molecules/cell in log phase SD medium. Belongs to the RRM MRD1 family.