Promoter Structure and Transcriptional Activation of the Murine TSG-14 Gene Encoding a Tumor Necrosis Factor/Interleukin-1-inducible Pentraxin Protein

Abstract

Human TNF-stimulated gene 14 (TSG-14) encodes a secreted 42-kDa glycoprotein that shows significant homology to proteins of the pentraxin family, which includes the acute phase reactants C-reactive protein and serum amyloid P component. Levels of TSG-14 protein (also termed PTX-3) become elevated in the serum of mice and humans after injection with bacterial lipopolysaccharide, but in contrast to conventional acute phase proteins, the bulk of TSG-14 synthesis in the intact organism occurs outside the liver. In the present study we cloned and partially sequenced murine genomic TSG-14 DNA. Analysis of the coding region predicts a high degree of amino acid sequence homology between murine and human TSG-14 (88 and 75% identity in the first and second exons, respectively). The promoter of the TSG-14 gene lacks consensus sequences for either a TATA box or CCAAT box. Primer extension analysis and S1 nuclease protection assay revealed one major transcription start site, situated within a consensus sequence for an initiator element. Sequence analysis of a approximately 1.4-kilobase pair fragment of the 5'-flanking region of the TSG-14 gene revealed the presence of numerous potential enhancer binding elements, including six NF-IL6-like sites, four AP-1, one AP-2, one NF-kB, two Sp1, two interferon-gamma-activated sites (GAS), one Hox-1.3, and five binding sites for Ets family members. Transfection of BALB/c 3T3 cells with promoter DNA fragments linked to the luciferase reporter gene revealed that the 5'-flanking region of the TSG-14 gene comprises elements that can mediate a basal level of transcription and inducibility by TNF.