Isolation and characterization of the Xenopus HIVEP gene family

The HIVEP gene family encodes for very large sequence-specific DNA binding proteins containing multiple zinc fingers. Three mammalian paralogous genes have been identified, HIVEP1, -2 and -3, as well as the closely related Drosophila gene, Schnurri. These genes have been found to directly participate in the transcriptional regulation of a variety of genes. Mammalian HIVEP members have been implicated in signaling by TNF-alpha and in the positive selection of thymocytes, while Schnurri has been shown to be an essential component of the TGF-beta signaling pathway. In this study, we describe the isolation of Xenopus HIVEP1, as well as partial cDNAs of HIVEP2 and -3. Analysis of the temporal and spatial expression of the XHIVEP transcripts during early embryogenesis revealed ubiquitous expression of the transcripts. Assays using Xenopus oocytes mapped XHIVEP1 domains that are responsible for nuclear export and import activity. The DNA binding specificity of XHIVEP was characterized using a PCR-mediated selection and gel mobility shift assays.