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.
Laboratory of Biochemistry and Molecular Biology, CNRS EP 89, IFR 53-Biomolecules, Faculty of Medicine, University of Reims Champagne-Ardenne, France.
P
P
Gillery
N
N
Georges
A
A
Randoux
F
F
Lefèvre
F X
FX
Maquart
J P
JP
Borel
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