Characterization of a 5'-flanking region supporting the transcription of mouse thymosin β-4 in mouse NIH3T3 cells

Expression of the gene coding for thymosin β-4 (Tβ-4), the major G- actin sequestering peptide in the cell, is regulated mainly at the level of transcription. In this study, we examined the nucleotide sequence of the 5'- flanking region (from - 2202 to 881) of the mouse Tβ-4 gene, and demonstrated that the DNA fragment from-278 to +410 of this gene was capable of directing the expression of a chloramphenicol acetyltransferase reporter gene in NIH3T3 cells. However, expression of the reporter gene in cells cannot be induced by interferon-α treatment even though a rapid activation of endogenous Tβ-4 gene by this cytokine was observed. These results suggest that the projected interferon-stimulated response element (ISRE) might reside in other parts of the mouse Tβ-4 gene.