Gene structure and evolution of Tieg3, a new member of the Tieg family of proteins

Abstract

TGFbeta-inducible immediate early gene, Tieg, belongs to the superfamily of Spl-like transcription factors containing three C(2)H(2)-zinc finger DNA binding motifs close to the C-terminus. So far, Tieg 1 and Tieg2 have been identified in human and mouse. We identified Tieg3 a new member of the Tieg protein family by screening a mouse cDNA library. Tieg3 has almost all the known features of the Tieg protein family: it shares a highly conserved C(2)H(2) zinc finger DNA binding domain and is 96% identical to Tieg2 and 86% to Tieg1, respectively. In addition, the three repression domains at the N-terminus, R1, R2, and R3 are conserved in all the-Tiegs. Similar to Tieg1 and,Tieg2, Tieg3 mRNA is up-regulated in response to TGFbeta1 treatment and can perform the Sp1 sites mediated repression of transcription.: A 4 kilobase (kb) long transcript of mouse Tieg3 can be detected using Northern-blot analysis. The gene of mouse Teg3 contains four exons. Due to. the amino acid sequence similarity, mouse Tieg2 is regarded as an orthologue of human Tieg2. However, the mouse Tieg3 gene is localized in a conserved segment on. mouse chromosome 12 corresponding to human Tieg2 on chromosome 2 with the same gene order. An interesting explanation for this apparent contradiction might be a homologous recombination leading to loci exchange between the mouse Tieg3 and Tieg2. (C) 2003 Elsevier B.V. All rights reserved.