Required for efficient biogenesis of the 60S ribosomal subunit. Associates with nucleolar pre-ribosomal particles. Interacts with DBP6. Together with DBP6, NOP8, URB1 and URB2, forms an RNA-independent complex, which is required during early maturation of nascent 60S ribosomal subunits. Present with 2940 molecules/cell in log phase SD medium. Belongs to the RSA3 family.