Modulation of protein synthesis by extracellular matrix: potential involvement of two nucleolar proteins, nucleolin and fibrillarin.
Fibroblasts cultivated in a collagen matrix exhibit a large decrease in the synthesis of most proteins, depending on transcriptional and posttranscriptional controls. We have previously shown that ribosomal RNA content and half-life were decreased in collagen lattice cultures. Here, we cultivated human dermal fibroblasts in monolayers and in lattices and studied by competitive RT-PCR analysis the expression of the nucleolar proteins nucleolin and fibrillarin, two key factors in ribosome processing and association. Nucleolin expression was found increased, and fibrillarin expression decreased, in collagen-lattice vs monolayer-cultured fibroblasts, with some variability according to the strains (+25 to +250% and -40 to -60%, respectively). These data suggest that a possible trouble of the association between neosynthesized rRNA and nucleolar proteins is, at least partly, responsible for the inhibition of protein synthesis induced by the extracellular matrix.
Gillery
P
P
Laboratory of Biochemistry and Molecular Biology, CNRS EP 89, IFR 53-Biomolecules, Faculty of Medicine, University of Reims Champagne-Ardenne, France.
Georges
N
N
Randoux
A
A
Lefèvre
F
F
Maquart
F X
FX
Borel
J P
JP
D002478:Cells, Cultured; D002868:Chromosomal Proteins, Non-Histone / Q000096:biosynthesis*; D003094:Collagen; D005109:Extracellular Matrix / Q000502:physiology*; D005347:Fibroblasts; D006801:Humans; D009687:Nuclear Proteins / Q000096:biosynthesis*; D010750:Phosphoproteins / Q000096:biosynthesis*; D016133:Polymerase Chain Reaction; D012322:RNA Precursors / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D016601:RNA-Binding Proteins; D000097796:Nucleolin
D002868:Chromosomal Proteins, Non-Histone; D003094:Collagen; D009687:Nuclear Proteins; D010750:Phosphoproteins; D012322:RNA Precursors; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D000097796:Nucleolin; C047458:fibrillarin