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. Author manuscript; available in PMC: 2013 Dec 6.
Published in final edited form as: Subcell Biochem. 2012;61:10.1007/978-94-007-4525-4_10. doi: 10.1007/978-94-007-4525-4_10

Fig. 10.1. Mammalian rDNA repeat and 47S rRNA promoter.

Fig. 10.1

The top panel illustrates key elements and the general organisation of a mammalian rDNA repeat. The IGS includes the spacer and 47S rRNA promoters, enhancer repeats and the TTF-I binding sites T0 and Tsp. Arrows indicate start sites and direction of transcription. The coding region contains 5′ and 3′ external transcribed spacer (ETS) and two internal transcribed spacer (ITS) regions, along with regions encoding 18S, 5.8S and 28S rRNAs. Terminator elements (T1-10) downstream of the 47S rRNA gene are also indicated. The lower panel illustrates the layout of the 47S rRNA promoter, which directs the assembly of the Pol I PIC and consists of an upstream control element, and a core promoter element overlapping the transcription start site.