Résumé
A recessive mutant cell line, B7, which is partially responsive to both interferon (IFN)-(alpha and IFN-gamma is described. B7 was FACS sorted from a cellular pool, which was obtained from the parental cell line 2C4 after several rounds of mutagenesis. The partial responsiveness to IFN was observed both in terms of expression of cell surface markes (CD2, class I and II HLAS) and mRNA expression of IFN-stimulated genes (9-27; 6-16; 2'-5' OAS; GBP and HLA-DRalpha). A genetic cross with the U4 mutant (JAK I -, a member of the Janus family of nonr ceptor tyrosine kinase) did not restore full IFN responsiveness to B7 and JAK1 cDNA transfection into B7 restored the wild phenotype of the cell line, defining B7 as a member of the U4 complementation group. Nevertheless, JAK1 mRNA was not detected in this mutant Transcriptional regulator complexes such as IRF 1/2 (IFN-regulatory factor) and ISGF3gamma (IFN-stimulated gene factor) were constitutively formed in the B7 mutant and co-migrated with the IFN-induce complexes expressed in the parental cell line 2C4. Thus, this cell line seems to be useful for understanding cis-acting elements governing JAK1 mRNA expression.
Sujets)
Lignée de cellules transformées/effets des médicaments et des substances chimiques , Interféron alpha/pharmacologie , Interféron gamma/pharmacologie , Mutagenèse , Techniques de culture cellulaire , ADN complémentaire/isolement et purification , Électrophorèse , Cytométrie en flux , Activation de la transcription/effets des médicaments et des substances chimiquesRésumé
The extract of black and green tea (Camellia sp.) which are widely consumed as commonest beverage, decreased the 12-O-Tetradecanoylphorbol-13 acetate (TPA) induced promotion of transformation in dose dependent manner in JB6 mouse epidermal cell system. The probable mechanisms have been discussed.