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. Author manuscript; available in PMC: 2010 Jun 16.
Published in final edited form as: Hematol Oncol Clin North Am. 2009 Apr;23(2):261–282. doi: 10.1016/j.hoc.2009.01.004

Fig. 4. Putative biochemical function for Treacle, Dyskerin, Rps19/Rps24, RMRP, and Sbds in ribosomal biogenesis.

Fig. 4

A simplified version of the human pre-rRNA processing pathway is shown. Functions are deduced from data for either yeast or human orthologs. Mature rRNA species (denoted in bold) are liberated from the 45S pre-rRNA primary transcript by a series of processing steps. 5′ and 3′ ETS represent external transcribed sequences found on the 5′ and 3′ ends of the primary transcript, respectively. ITS represents internal transcribed sequences present in the primary transcript that are not retained in mature rRNAs. The 18S rRNA is a component of the 40S ribosomal subunit. The 5.8S and 28S rRNAs, together with the 5S rRNA (not shown), are components of the 60S ribosomal subunit.