Identification and characterization of SKAT-2, a novel Th2-specific zinc finger gene

We have identified a novel Kruppel-type zinc finger (ZF) gene, SKAT-2, whic h is selectively expressed by murine Th2 cells. The protein encoded by this gene has 14 C2H2-type ZF tandemly arrayed at its C terminus and N-terminal SCAN box and KRAB domains. SKAT-2 is tissue restricted in expression at th e RNA level, detectable only in brain and at low levels in kidney and splee n and few hematopoietic cell lines. By in situ hybridization, SKAT-2 expres sion was found to peak in antigen-stimulated CD4(+) T cells after 2-3 days of culture under Th2 but not Th1 biasing conditions. This pattern of expres sion closely mirrored that of GATA-3 in the same cells. In transient transf ection experiments in phorbol 12-myristate 13-acetate/ ionomycin-stimulated EL4 cells, SKAT-2 was found to up-regulate the activity of the IL-4 but no t the IL-5 promoter, contrasting with the ability of GATA-3 to activate bot h promoters. This result was confirmed using clones of EL4 cells stably exp ressing an inducible form of SKAT-2, thus SKAT-2 is a novel The-specific ge ne that may play a role in selective regulation of cytokine genes in T cell s.