REGULATION OF T-CELL RECEPTOR-GAMMA GENE-EXPRESSION BY CYTOKINES IN MURINE HEMATOPOIETIC-CELLS

Murine IL-3-dependent myeloid cell lines express transcripts from non- rearranged TCR gamma genes and this expression is dependent upon IL-3. To investigate this observation in general terms we examined various IL-3 dependent cell lines for TCR gamma gene expression. We also exami ned various cytokines to test their potential to induce TCR I gene exp ression, All IL-3 dependent cell lines expressed TCR gamma transcripts . The IL-3 induced expression was sensitive to protein synthesis inhib itors, This demonstrated that the TCR gamma genes belong to the early growth factor response class. IL-3, IL-4, GM-CSF and Erytropoietin (EP O), but not G-CSF, induced TCR gene expression. 32D cells transfected with the IL-2 beta chain receptor became responsive to IL-2 as a growt h factor and induced TCR gamma gamma gene expression. The induction of TCR gamma gene expression by the cytokines was not correlated to thei r growth promoting activity. This indicated different signaling pathwa ys.