Gamma interferon potently induces tryptophanyl-tRNA synthetase expression in human keratinocytes.
Incubation of human keratinocytes with gamma interferon (gamma-IFN) induces the synthesis of a 53-kDa protein of unknown nature and function. We report the identification of this protein through amino acid microsequencing. The NH2-terminal amino acid sequence of the 53-kDa antigen demonstrated that this protein was tryptophanyl-tRNA synthetase (Frolova et al, Gene 109:291-296, 1991, Genbank accession number 61715). This result was validated by the sequencing of tryptic peptides. Identification of the 53-kDa gamma-IFN-induced protein was confirmed by immunoblotting with an antiserum directed against beef pancreas tryptophanyl-tRNA synthetase. Northern blot analysis using a synthetic oligonucleotidic 32P-labeled probe evidenced a 3.1-kb transcript in gamma-IFN-treated cells indicating that the gene was regulated at the pre-translational level. These data show that gamma-IFN potently induces in keratinocytes the expression of an enzyme directly involved in protein biosynthesis. Elevated levels of tryptophanyl-tRNA synthetase in treated cultured keratinocytes might be involved in the cell-growth-inhibitory activity of gamma interferon.
Laboratoire de Recherche, Peau Humaine et Immunité, INSERM U, Lyon, France.
A
A
Reano
M H
MH
Richard
L
L
Denoroy
J
J
Viac
J P
JP
Benedetto
D
D
Schmitt
D000595:Amino Acid Sequence; D015152:Blotting, Northern; D004790:Enzyme Induction / Q000187:drug effects; D006801:Humans; D015151:Immunoblotting; D007371:Interferon-gamma / Q000494:pharmacology*; D015603:Keratinocytes / Q000201:enzymology*; D008969:Molecular Sequence Data; D014369:Tryptophan-tRNA Ligase / Q000096:biosynthesis*
D007371:Interferon-gamma; D014369:Tryptophan-tRNA Ligase