FIGURE 2.
Secondary structure model and functional map of 5′ ETS. The model is based on cryo-EM structure of 90S and secondary structure prediction. The ten helices of 5′ ETS are termed H1 to H10. The four intermolecular helices between pre-18S and U3 snoRNA are termed Ha to Hd. The A0 and A1 sites are marked. Parts of 18S RNA (blue) and U3 snoRNA (red) are displayed. The sequence of 5′ ETS is color-shaped according to their functional importance for 18S rRNA processing. 18S/pre-18S > 16, gray; 8–16, yellow; 3–8, orange; <3 red; blue, minimal length required.
