Assembly of the 30S ribosomal subunit

Culver, Gloria M.

doi:10.1002/bip.10221

Cited by 119 publications

(82 citation statements)

References 129 publications

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“…[13][14][15][16] The third stage of assembly involves the association of the remaining r-proteins (the tertiary binding proteins: S2, S3, S10, S14 and S21; see Figure 1(a)) with RI* resulting in the formation of functional 30 S subunits (Figure 1(b), stage III). These three stages of assembly correspond well with assembly events described in the assembly map, 2,3,7 and with in vivo findings. [8][9][10][11][12] An understanding of details associated with each of these stages should yield an abundance of information regarding assembly of functional 30 S subunits.…”

Section: Introductionsupporting

confidence: 87%

“…6 These studies culminated in the synthesis of an in vitro assembly map that illustrates the cooperative and hierarchical nature of 30 S subunit assembly (Figure 1(a)). 2,3,7 This map reveals that the r-proteins can be classified into three main groups: the primary binding proteins (S4, S7, S8, S15, S17, and S20), which are able to bind directly and independently to 16 S rRNA; the secondary binding proteins (S5, S6, S9, S11-S13, S16, S18, and S19), which require the association of a primary r-protein with 16 S rRNA prior to their binding; and the tertiary binding proteins (S2, S3, S10, S14, and S21), which require that at least one primary and secondary r-protein are associated with the assembling ribonucleoprotein (RNP) particle prior to their association with the complex.…”

Section: Introductionmentioning

confidence: 99%

“…While we cannot preclude the (a) Modified in vitro 30 S subunit assembly map. 2,3,7 The 16 S rRNA is represented by a rectangle in a 5 0 to 3 0 direction. The red, green, and blue arrows indicate the proteins that compose the body, platform, and head of the 30 S subunit, respectively.…”

Section: Introductionmentioning

confidence: 99%

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Analysis of Conformational Changes in 16 S rRNA During the Course of 30 S Subunit Assembly

Holmes

Culver

2005

Journal of Molecular Biology

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Section: Introductionsupporting

confidence: 87%

Section: Introductionmentioning

confidence: 99%

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Analysis of Conformational Changes in 16 S rRNA During the Course of 30 S Subunit Assembly

Holmes

Culver

2005

Journal of Molecular Biology

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“…Many of these conformations are nonfunctional and represent kinetic traps that must be overcome, especially at low temperatures. During ribosome biogenesis, these kinetic traps and energy barriers are thought to be overcome in part by AFs and r-proteins (2,71).…”

Section: Discussionmentioning

confidence: 99%

Ribosome Assembly Factors Pwp1 and Nop12 Are Important for Folding of 5.8S rRNA during Ribosome Biogenesis in Saccharomyces cerevisiae

Talkish

Campbell

Sahasranaman

et al. 2014

Molecular and Cellular Biology

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Previous work from our lab suggests that a group of interdependent assembly factors (A 3 factors) is necessary to create early, stable preribosomes. Many of these proteins bind at or near internal transcribed spacer 2 (ITS2), but in their absence, ITS1 is not removed from rRNA, suggesting long-range communication between these two spacers. By comparing the nonessential assembly factors Nop12 and Pwp1, we show that misfolding of rRNA is sufficient to perturb early steps of biogenesis, but it is the lack of A 3 factors that results in turnover of early preribosomes. Deletion of NOP12 significantly inhibits 27SA 3 pre-rRNA processing, even though the A 3 factors are present in preribosomes. Furthermore, pre-rRNAs are stable, indicating that the block in processing is not sufficient to trigger turnover. This is in contrast to the absence of Pwp1, in which the A 3 factors are not present and pre-rRNAs are unstable. In vivo RNA structure probing revealed that the pre-rRNA processing defects are due to misfolding of 5.8S rRNA. In the absence of Nop12 and Pwp1, rRNA helix 5 is not stably formed. Interestingly, the absence of Nop12 results in the formation of an alternative yet unproductive helix 5 when cells are grown at low temperatures. Ribosome assembly is a highly conserved and dynamic process driven by the cooperative transcription, folding, modification, and processing of rRNAs and stable binding of ribosomal proteins (r-proteins) (1, 2). In Saccharomyces cerevisiae, this process begins in the nucleolus with cotranscriptional assembly of early precursor particles. As transcription proceeds, the nascent pre-rRNA is cleaved, separating maturation of early 40S and 60S precursors. A series of endo-and exonucleolytic cleavages remove internal and external transcribed spacer sequences from prerRNAs, as the assembling ribosome moves from the nucleolus to the nucleoplasm and is eventually exported to the cytoplasm ( Fig. 1A and B).Assembly of yeast ribosomes requires ϳ180 trans-acting proteins termed assembly factors (AFs). The majority of these proteins are conserved across eukaryotes, are essential for cell growth, and are thought to function as scaffolding proteins, RNA chaperones, energy-consuming nucleoside triphosphatases (NTPases), nucleases, or posttranslational modifiers (3-5). Purification of ribosome assembly intermediates allowed the identification of most AFs, and initial characterizations have shown in which steps of pre-rRNA processing many of these factors function. However, to begin to understand the function of these proteins on a mechanistic level, one must address the following: the timing of association of these proteins with preribosomes; how they are recruited to preribosomes; their requirement for the stable binding of other proteins; and their role in folding rRNA.Numerous studies have shown that subsets of AFs can be isolated as subcomplexes (6-23). Proteins within a subcomplex are often required for the same steps of pre-rRNA processing, suggesting that they function together during ribosome bi...

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“…When two equivalents of [Cu(CH 3 CN) 4 (PF 6 )] in acetonitrile were added to a chloroform solution of 2, the quantitative formation of the cryptate [Cu 2 (2)(PF 6 ) 2 ] was observed, as evidenced by 1 H NMR spectroscopy and ESI mass spectrometry. Most likely, the Cu + ions are bound to the N atoms of the cage, as was observed for smaller tren-based cryptands.…”

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confidence: 99%