Presumably a zinc binding domain, which has been shown to bind to DNA in the human nuclear transcriptional repressor NF-X1. The zinc finger can be characterized by the pattern C-X(1-6)-H-X-C-X3-C(H/C)-X(3-4)-(H/C)-X(1-10)-C. The NF-X1 zinc finger co-occurs with atypical RING-finger and R3H domains. Human NF-X1 is involved in the transcriptional repression of major histocompatibility complex class II genes. The drosophila homolog encoded by stc (shuttle craft) plays a role in embryonic development, and the Arabidopsis homologue AtNFXL1 has been shown to function in the response to trichothecene and other defense mechanisms.