32S pre-rRNA is nucleolytically processed at site 4 (4a) to yield 12S pre-rRNA and 28S rRNA

Stable Identifier
Reaction [omitted]
Homo sapiens
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Unknown nucleases process the 32S precursor rRNA (pre-rRNA) at site 4, yielding the 28S rRNA and the 12S pre-RNA that will be further processed to the mature 5.8S rRNA. Processing occurs in precursor 60S ribosomal (pre-60S) subunits that contain ribosomal proteins and processing factors. The PES1:BOP1:WDR12 complex (PeBoW complex) associates with pre-60S subunits in both the nucleus and cytosol where it is involved in processing 32S rRNA and recycling pre-60S subunit processing factors. Perturbation of the PeBoW complex prevents processing of the 32S pre-rRNA (Holzel et al. 2005, Grimm et al. 2006, Holzel et al 2007, Rohrmoser et al. 2007). The polynucleotide kinase activity of NOL9, which is associated with pre-60s subunits, is also required for processing of pre-32S rRNA (Heindl and Martinez 2010). LAS1L interacts with PELP1:TEX10:WDR18, NOL9, and SENP3 in pre-60S subunits where it is required for processing of the internal transcribed spacer 2 (ITS2) in pre-32S rRNA (Castle et al. 2012). The PELP1:TEX10:WDR18 complex is the mammalian homolog of the yeast Rix1 complex (Castle et al. 2012). A complex containing GNL3 (Nucleostemin), EBNA1BP2, DDX21, and PES1 is also required for processing 32S rRNA to 28S rRNA (Romanova et al. 2009). Both the Nucleostemin complex and the PeBoW complex both contain PES1 and therefore may be part of a single larger complex.

Literature References
PubMed ID Title Journal Year
17353269 Interdependence of Pes1, Bop1, and WDR12 controls nucleolar localization and assembly of the PeBoW complex required for maturation of the 60S ribosomal subunit

Gruber-Eber, A, Harasim, T, Grimm, T, Malamoussi, A, Eick, D, Orban, M, Rohrmoser, M, Kremmer, E, Pfisterer, I, Hölzel, M

Mol. Cell. Biol. 2007
16738141 Dominant-negative Pes1 mutants inhibit ribosomal RNA processing and cell proliferation via incorporation into the PeBoW-complex

Gruber-Eber, A, Harasim, T, Grimm, T, Malamoussi, A, Eick, D, Rohrmoser, M, Kremmer, E, Hölzel, M

Nucleic Acids Res. 2006
21063389 Nol9 is a novel polynucleotide 5'-kinase involved in ribosomal RNA processing

Martinez, J, Heindl, K

EMBO J. 2010
16043514 Mammalian WDR12 is a novel member of the Pes1-Bop1 complex and is required for ribosome biogenesis and cell proliferation

Gruber-Eber, A, Schlee, M, Harasim, T, Grimm, T, Malamoussi, A, Eick, D, Bornkamm, GW, Rohrmoser, M, Hiddemann, W, Kremmer, E, Hölzel, M

J. Cell Biol. 2005
17189298 The BRCT domain of mammalian Pes1 is crucial for nucleolar localization and rRNA processing

Gruber-Eber, A, Harasim, T, Grimm, T, Malamoussi, A, Eick, D, Rohrmoser, M, Kremmer, E, Hölzel, M

Nucleic Acids Res. 2007
22190735 LAS1L interacts with the mammalian Rix1 complex to regulate ribosome biogenesis

Denicourt, C, Cassimere, EK, Castle, CD

Mol. Biol. Cell 2012
19106111 Critical role of nucleostemin in pre-rRNA processing

Rayner, S, Katoku-Kikyo, N, Kellner, S, Grand, A, Zhang, L, Kikyo, N, Romanova, L

J. Biol. Chem. 2009
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