The distribution of plastid ribosomes and the integrity of plastid ribosomal RNA during the greening and maturation of Spirodela fronds

1974 ◽  
Keyword(s):  
Ribosomal Rna ◽  
Plastid Ribosomes

scholarly journals Rerouting of ribosomal proteins into splicing in plant organelles

2020 ◽  
Vol 117 (47) ◽  
pp. 29979-29987
Author(s):  
Chuande Wang ◽  
Rachel Fourdin ◽  
Martine Quadrado ◽  
Céline Dargel-Graffin ◽  
Dimitri Tolleter ◽  
...  
Keyword(s):  
Ribosomal Rna ◽  
Ribosomal Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Binding Capacity ◽  
Evolutionary Strategy ◽  
Conserved Domain ◽  
The Family ◽  
Plastid Ribosomes ◽  
Plant Organelles

Production and expression of RNA requires the action of multiple RNA-binding proteins (RBPs). New RBPs are most often created by novel combinations of dedicated RNA-binding modules. However, recruiting existing genes to create new RBPs is also an important evolutionary strategy. In this report, we analyzed the eight-member uL18 ribosomal protein family inArabidopsis. uL18 proteins share a short structurally conserved domain that binds the 5S ribosomal RNA (rRNA) and allows its incorporation into ribosomes. Our results indicate thatArabidopsisuL18-Like proteins are targeted to either mitochondria or chloroplasts. While two members of the family are found in organelle ribosomes, we show here that two uL18-type proteins function as factors necessary for the splicing of certain mitochondrial and plastid group II introns. These two proteins do not cosediment with mitochondrial or plastid ribosomes but instead associate with the introns whose splicing they promote. Our study thus reveals that the RNA-binding capacity of uL18 ribosomal proteins has been repurposed to create factors that facilitate the splicing of organellar introns.

Visualisation of E. coli ribosomal RNA in situ by electron spectroscopic imaging and image averaging

1992 ◽  
Vol 50 (1) ◽  
pp. 466-467
Author(s):  
Daniel Beniac ◽  
George Harauz
Keyword(s):  
Ribosomal Rna ◽  
Three Dimensional ◽  
Spectroscopic Imaging ◽  
Electron Spectroscopic Imaging ◽  
E Coli ◽  
Microscopical Technique ◽  
Quantitative Image ◽  
Dimensional Reconstruction ◽  
Image Averaging ◽  
Protein Components

The structures of E. coli ribosomes have been extensively probed by electron microscopy of negatively stained and frozen hydrated preparations. Coupled with quantitative image analysis and three dimensional reconstruction, such approaches are worthwhile in defining size, shape, and quaternary organisation. The important question of how the nucleic acid and protein components are arranged with respect to each other remains difficult to answer, however. A microscopical technique that has been proposed to answer this query is electron spectroscopic imaging (ESI), in which scattered electrons with energy losses characteristic of inner shell ionisations are used to form specific elemental maps. Here, we report the use of image sorting and averaging techniques to determine the extent to which a phosphorus map of isolated ribosomal subunits can define the ribosomal RNA (rRNA) distribution within them.

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