Characterization of the Promoter for the Human Long Pentraxin PTX3

Abstract

The "long pentraxins" are an emerging family of genes that have conserved in their carboxy-terminal halves a pentraxin domain homologous to the prototypical acute phase protein pentraxins (C-reactive protein and serum amyloid P component) and acquired novel amino-terminal domains. In this report, a genomic fragment of 1371 nucleotides from the human "long pentraxin" gene PTX3 is characterized as a promoter on tumor necrosis factor-␣ (TNF␣) and interleukin (IL)-1␤ exposure in transfected 8387 human fibroblasts by chloramphenicol acetyltransferase and RNase protection assays. In the same cells, the PTX3 promoter does not respond to IL-6 stimulation. Furthermore, IL-1␤ and TNF␣ responsiveness is not seen in the Hep 3B hepatoma cell line. The minimal promoter contains one NF-B element which is shown to be necessary for induction and able to bind p50 homodimers and p65 heterodimers but not c-Rel. Mutants in this site lose the ability to bind NF-B proteins and to respond to TNF␣ and IL-1␤ in functional assays. Sp1-and AP-1 binding sites lying in proximity to the NF-B site do not seem to play a major role for cytokine responsiveness. Finally, cotransfection experiments with expression vectors validate that the natural promoter contains a functional NF-B site.The human gene hPTX3 has been recently cloned from interleukin-1␤ (IL-1b) 1 -stimulated endothelial cells (1) and from tumor necrosis factor-␣ (TNF␣)-stimulated fibroblasts (2). PTX3 belongs to the family of pentraxins (so named because they are assembled in pentamers) that include C-reactive protein (CRP) and serum amyloid P component (SAP) from several different species (3) and which are markers of the acute phase. Moreover, while the 3Ј half of PTX3 can be aligned with the full-length sequences of CRP and SAP (4) (pentraxin domain), the 5Ј half of the protein does not show significant homology with other known proteins.

Production of the soluble pattern recognition receptor PTX3 by myeloid, but not plasmacytoid, dendritic cells

“…TIRAP/MAL) [24,32], and to induce the production of selected downstream effector molecules, such as the interferon (IFN)-inducible chemokine CXCL10. The finding that agonists of different TLR induce production of PTX3, a NF-‹ B-regulated gene [40,41], suggests that PTX3 is downstream of the common core signaling MyD88 pathway.…”

Cell-specific Regulation of PTX3 by Glucocorticoid Hormones in Hematopoietic and Nonhematopoietic Cells

“…GC exert many anti-inflammatory actions by interfering with other signaling pathways, and GR interactions with NFB and AP-1 occur in GR dim/dim mice, in which GR-mediated gene activation is impaired (32,45). The human and murine PTX3 promoters have both been characterized, and NFB plays a pivotal role in PTX3 gene regulation (36,37). More recently, PTX3 has been shown to be regulated by the FUS/CHOP oncogene (46,47).…”

“…PTX3 promoter was found to contain binding sites for the transcription factors NFB and AP-1, which confer responsiveness to IL-1␤, LPS, and TNF␣ (36,37). We investigated whether GC directly modulates PTX3 gene expression.…”

Tumor Necrosis Factor-α Regulates Expression of Vascular Endothelial Growth Factor Receptor-2 and of Its Co-receptor Neuropilin-1 in Human Vascular Endothelial Cells

“…This cell line was selected instead of endothelial cells, because it was more easily transfected with the construct than endothelial cells and expresses a functional active TNF receptor (29). Analysis of the respective luciferase expressions in untreated and TNF-␣-stimulated cells revealed notable basal activity of the pGL2basicFlk-1 construct, which was increased after treatment with the cytokine by a factor of 2 (Fig.…”