The gene for yeast ribosomal protein S31 contains an intron in the leader sequence.

Analysis of the primary structure of the gene for yeast ribosomal protein S31 revealed two unusual features. First, an intron of 312 nucleotides is located within the 5'-untranslated region. Second, the coding sequence for the known amino-terminal peptide of the protein starts 13 codons downstream of the ATG initiation codon, suggesting that S31 is synthesized as a precursor which undergoes post-translational processing to the mature protein. Primer extension analysis showed that transcription of the S31 gene starts at multiple sites. The 5'-flanking region of the gene contains several, previously described, conserved sequence elements that may play a role in the coordinate expression of yeast ribosomal protein genes.