Figure 1 from Venema and Tollervey, (1999) Ann. Rev. of Genetics:261-311.

Figure 1 from Venema, J. and D. Tollervey. (1999) Ribosome Synthesis in Saccharomyces cerevisiae. Annual Review of Genetics 33: 261-311.

Figure Legend: Structure and processing of the pre-rRNA in Saccharomyces cerevisiae. The yeast rDNA unit is 9.1 kb long and consists of the 35S pre-rRNA operon and two nontranscribed spacers, NTS1 and NTS2, interrupted by the 5S rRNA gene. The 35S pre-rRNA operon contains the sequences for the mature 18S, 5.8S, and 25S rRNAs separated by the two internal transcribed spacers, ITS1 and ITS2, and flanked at either end by two external transcribed spacers, the 5' -ETS and 3' -ETS. The location of the known processing sites is also indicated. [Note from SGD: Processing sites are designated with capital letters; eg: A0, A1, D, E.]