You know what the site of protein synthesis is-ribosome. Ribosomes are made up of ribosomal proteins and rRNA. (cool huh, protein synthesizer is made of proteins) RNA is of three types based on their function: 1. mRNA 2. tRNA 3. rRNA (stated above) DNA is in the nucleus.But ribosomes for protein synthesis are OUTSIDE the nucleus (in the cytoplasm, RER).o read the mRNA, ribosomes are used and these are made of rRNA (ribosomal RNA) which form subunits to give the ribosome. The last RNA is tRNA (transfer RNA) which brings the correct amino acid to the ribosome and mRNA complex and add it to the growing polypeptide chain which would eventually form the protein.