Structure of the Exon Junction Core Complex with a Trapped DEAD-Box ATPase Bound to RNA

Science ◽  
2006 ◽  
Vol 313 (5795) ◽  
pp. 1968-1972 ◽  
Author(s):  
C. B. F. Andersen
Keyword(s):  
Core Complex ◽  
Exon Junction ◽  
Dead Box

The exon junction core complex is locked onto RNA by inhibition of eIF4AIII ATPase activity

2005 ◽  
Vol 12 (10) ◽  
pp. 861-869 ◽  
Author(s):  
Lionel Ballut ◽  
Brice Marchadier ◽  
Aurélie Baguet ◽  
Catherine Tomasetto ◽  
Bertrand Séraphin ◽  
...  
Keyword(s):  
Atpase Activity ◽  
Core Complex ◽  
Exon Junction

scholarly journals P-body assembly requires DDX6 repression complexes rather than decay or Ataxin2/2L complexes

2015 ◽  
Vol 26 (14) ◽  
pp. 2579-2595 ◽  
Author(s):  
Jessica Ayache ◽  
Marianne Bénard ◽  
Michèle Ernoult-Lange ◽  
Nicola Minshall ◽  
Nancy Standart ◽  
...  
Keyword(s):  
Posttranscriptional Regulation ◽  
Affinity Purification ◽  
Rna Helicase ◽  
Exon Junction Complex ◽  
Key Factors ◽  
P Bodies ◽  
Exon Junction ◽  
Dead Box ◽  
Repression Complex ◽  
High Enrichment

P-bodies are cytoplasmic ribonucleoprotein granules involved in posttranscriptional regulation. DDX6 is a key component of their assembly in human cells. This DEAD-box RNA helicase is known to be associated with various complexes, including the decapping complex, the CPEB repression complex, RISC, and the CCR4/NOT complex. To understand which DDX6 complexes are required for P-body assembly, we analyzed the DDX6 interactome using the tandem-affinity purification methodology coupled to mass spectrometry. Three complexes were prominent: the decapping complex, a CPEB-like complex, and an Ataxin2/Ataxin2L complex. The exon junction complex was also found, suggesting DDX6 binding to newly exported mRNAs. Finally, some DDX6 was associated with polysomes, as previously reported in yeast. Despite its high enrichment in P-bodies, most DDX6 is localized out of P-bodies. Of the three complexes, only the decapping and CPEB-like complexes were recruited into P-bodies. Investigation of P-body assembly in various conditions allowed us to distinguish required proteins from those that are dispensable or participate only in specific conditions. Three proteins were required in all tested conditions: DDX6, 4E-T, and LSM14A. These results reveal the variety of pathways of P-body assembly, which all nevertheless share three key factors connecting P-body assembly to repression.

scholarly journals Perispeckles are major assembly sites for the exon junction core complex

2012 ◽  
Vol 23 (9) ◽  
pp. 1765-1782 ◽  
Author(s):  
Elisabeth Daguenet ◽  
Aurélie Baguet ◽  
Sébastien Degot ◽  
Ute Schmidt ◽  
Fabien Alpy ◽  
...  
Keyword(s):  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Ultrastructural Level ◽  
Exon Junction Complex ◽  
Nuclear Speckles ◽  
Core Complex ◽  
Exon Junction ◽  
Interchromatin Granule ◽  
Mrna Maturation ◽  
Transcription Sites

The exon junction complex (EJC) is loaded onto mRNAs as a consequence of splicing and regulates multiple posttranscriptional events. MLN51, Magoh, Y14, and eIF4A3 form a highly stable EJC core, but where this tetrameric complex is assembled in the cell remains unclear. Here we show that EJC factors are enriched in domains that we term perispeckles and are visible as doughnuts around nuclear speckles. Fluorescence resonance energy transfer analyses and EJC assembly mutants show that perispeckles do not store free subunits, but instead are enriched for assembled cores. At the ultrastructural level, perispeckles are distinct from interchromatin granule clusters that may function as storage sites for splicing factors and intermingle with perichromatin fibrils, where nascent RNAs and active RNA Pol II are present. These results support a model in which perispeckles are major assembly sites for the tetrameric EJC core. This subnuclear territory thus represents an intermediate region important for mRNA maturation, between transcription sites and splicing factor reservoirs and assembly sites.

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