title: Ribosomal protein mRNAs are translationally-regulated during human dendritic cells activation by LPS.
abstract: BACKGROUND
  Dendritic cells (DCs) are the sentinels of the mammalian immune system, characterized by a complex maturation process driven by pathogen detection. Although multiple studies have described the analysis of activated DCs by transcriptional profiling, recent findings indicate that mRNAs are also regulated at the translational level. A systematic analysis of the mRNAs being translationally regulated at various stages of DC activation was performed using translational profiling, which combines sucrose gradient fractionation of polysomal-bound mRNAs with DNA microarray analysis.
  
  
  RESULTS
  Total and polysomal-bound mRNA populations purified from immature, 4 h and 16 h LPS-stimulated human monocyte-derived DCs were analyzed on Affymetrix microarrays U133 2.0. A group of 375 transcripts was identified as translationally regulated during DC-activation. In addition to several biochemical pathways related to immunity, the most statistically relevant biological function identified among the translationally regulated mRNAs was protein biosynthesis itself. We singled-out a cluster of 11 large ribosome proteins mRNAs, which are disengaged from polysomes at late time of maturation, suggesting the existence of a negative feedback loop regulating translation in DCs and linking ribosomal proteins to immuno-modulatory function.
  
  
  CONCLUSIONS
  Our observations highlight the importance of translation regulation during the immune response, and may favor the identification of novel protein networks relevant for immunity. Our study also provides information on the potential absence of correlation between gene expression and protein production for specific mRNA molecules present in DCs.
authors: Centre d'Immunologie de Marseille-Luminy, Université de la Méditerranée, Case 906, 13288 Marseille cedex 9, France. m.ceppi@genomicvision.com
authors: Maurizio
authors: M
authors: Ceppi
authors: Giovanna
authors: G
authors: Clavarino
authors: Evelina
authors: E
authors: Gatti
authors: Enrico K
authors: EK
authors: Schmidt
authors: Aude
authors: A
authors: de Gassart
authors: Derek
authors: D
authors: Blankenship
authors: Gerald
authors: G
authors: Ogola
authors: Jacques
authors: J
authors: Banchereau
authors: Damien
authors: D
authors: Chaussabel
authors: Philippe
authors: P
authors: Pierre