RNA-binding nucleolar protein required for pre-rRNA processing. Component of the 90S pre-ribosome involved in production of 18S rRNA and assembly of small ribosomal subunit. Component of the pre-40S ribosome required for release from the nucleolus (By similarity). Component of the 90S pre-ribosome. Component of the pre-40S ribosome. Belongs to the NOP9 family.