Transcriptional induction of genes is an essential part of the cellular response to interferons. To isolate yet unidentified IFN-regulated genes we have performed a differential screening on a cDNA library prepared from human lymphoblastoid Daudi cells treated for 16 h with human alpha/beta interferon (Hu-alpha/beta IFN). In the course of these studies we have isolated a human cDNA which codes for a protein sharing homology with the mouse Rpt-1 gene; it will be referred as Staf-50 for Stimulated Trans-Acting Factor of 50 kDa. Amino acid sequence analysis revealed that Staf-50 is a member of the Ring finger family and contains all the features of a transcriptional regulator able to initiate a second cascade of gene induction (secondary response). Staf-50 is induced by both type I and type II IFN in various cell lines and down-regulates the transcription directed by the long terminal repeat promoter region of human immunodeficiency virus type 1 in transfected cells. These data are consistent with a role of Staf-50 in the mechanism of transduction of the IFN antiviral action.
Molecular cloning of a new interferon-induced factor that represses human immunodeficiency virus type 1 long terminal repeat expression
Tissot, C.; Mechti, N.
J Biol Chem
1995-06-23 / vol 270 / pages 14891-8
Humans; Amino Acid Sequence; Molecular Sequence Data; Base Sequence; Cell Line; Transcription, Genetic; Sequence Homology, Amino Acid; Transfection; Zinc Fingers; *Gene Expression Regulation, Viral; Hela Cells; Tumor Cells, Cultured; *HIV Long Terminal Repeat; Cloning, Molecular; DNA, Complementary; HIV-1/*genetics; Interferon-alpha/*pharmacology; Interferon-beta/*pharmacology; Repressor Proteins/biosynthesis/chemistry/*metabolism; Transcription Factors/biosynthesis/chemistry/*metabolism