Functional dichotomy of ribosomal proteins during the synthesis of mammalian 40S ribosomal subunits
نویسندگان
چکیده
منابع مشابه
Functional dichotomy of ribosomal proteins during the synthesis of mammalian 40S ribosomal subunits
Our knowledge of the functions of metazoan ribosomal proteins in ribosome synthesis remains fragmentary. Using siRNAs, we show that knockdown of 31 of the 32 ribosomal proteins of the human 40S subunit (ribosomal protein of the small subunit [RPS]) strongly affects pre-ribosomal RNA (rRNA) processing, which often correlates with nucleolar chromatin disorganization. 16 RPSs are strictly required...
متن کاملNuclear export and cytoplasmic processing of precursors to the 40S ribosomal subunits in mammalian cells.
It is generally assumed that, in mammalian cells, preribosomal RNAs are entirely processed before nuclear exit. Here, we show that pre-40S particles exported to the cytoplasm in HeLa cells contain 18S rRNA extended at the 3' end with 20-30 nucleotides of the internal transcribed spacer 1. Maturation of this pre-18S rRNA (which we named 18S-E) involves a cytoplasmic protein, the human homolog of...
متن کاملA factor for the binding of aminoacyl transfer RNA to mammalian 40S ribosomal subunits.
A factor present in rat liver supernatant catalyzes binding of Phe-tRNA to 40S ribosomal subunits from rat skeletal muscle. This factor could be distinguished from aminoacyltransferase I by a number of criteria: (1) at lower concentrations of magnesium (5 mM) the 40S binding factor was approximately seven times as effective as T-I in catalyzing binding of Phe-tRNA to 40S subunits; (2) the kinet...
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Exchange of ribosomal subunits (RSU) in the course of protein synthesis has been demonstrated in bacteria." 2 RSU have been shown to be stable during bacterial growth and to be continuously recycled through ribosomes.2 These results suggested that ribosomes dissociate into subunits between successive rounds of protein synthesis. The 30S E. coli RSU binds the initiator tRNA (formylmethionine-tRN...
متن کاملRio1 mediates ATP-dependent final maturation of 40S ribosomal subunits
During the last step in 40S ribosome subunit biogenesis, the PIN-domain endonuclease Nob1 cleaves the 20S pre-rRNA at site D, to form the mature 18S rRNAs. Here we report that cleavage occurs in particles that have largely been stripped of previously characterized pre-40S components, but retain the endonuclease Nob1, its binding partner Pno1 (Dim2) and the atypical ATPase Rio1. Within the Rio1-...
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ژورنال
عنوان ژورنال: Journal of Cell Biology
سال: 2010
ISSN: 1540-8140,0021-9525
DOI: 10.1083/jcb.201005117