rRNA itself is transcribed in the nucleolus, where ribosomes are assembled (from rRNA and ribosomal proteins) in totality. Keep in mind though, that the ribosomal proteins are translated from mRNA outside the nucleus and imported back in before they can be used for ribosome assembly in the nucleolus.Click to expand...ll RNA is produced in the nucleus. The thing about rRNA is that it is constitutively expressed. The rRNA genes are encoded for multiple times along the length of the genome.