Transcriptional regulation of TSG6, a tumor necrosis factor- and interleukin-1-inducible primary response gene coding for a secreted hyaluronan-binding protein.
TSG6 was originally identified as a tumor necrosis factor (TNF)-inducible gene in human fibroblasts. Earlier we showed that the secretory TSG6 protein is a member of a family of hyaluronan-binding proteins that includes cartilage link protein, proteoglycan core protein, and the adhesion receptor CD44. In the present study we have used Southern blot analysis to demonstrate that TSG6 is a single-copy gene in the human and murine species. With the aid of a somatic cell hybrid mapping panel, TSG6 was assigned to human chromosome 2. Nuclear run-on analysis revealed that TNF produced a rapid, primary transcriptional activation of the TSG6 gene in normal human FS-4 fibroblasts. In order to learn more about the regulation of TSG6 gene expression, we cloned the TSG6 gene from a genomic library of human white blood cells. Sequencing of a 1.3-kilobase fragment of the 5'-flanking region of the TSG6 gene identified TATA-like and CAAT sequences near the transcription start site. In addition, potential binding sites for NF-IL-6, AP-1, interferon regulatory factors (IRF)-1 and -2, and glucocorticoid response elements were identified in the 5'-flanking region. A single transcription start site was identified by primer extension. Deletion analysis of the 5'-flanking region of the TSG6 DNA linked to the chloramphenicol acetyltransferase reporter gene revealed that a construct containing TSG6 DNA from positions -165 to +78 could be transcriptionally activated by interleukin(IL)-1, and to a lesser extent by TNF, upon transfection into FS-4 fibroblasts. The region that imparts inducibility by IL-1 or TNF (positions -165 to -58) contains potential binding sites for IRF-1 and -2, AP-1, and NF-IL-6. A region mediating transcriptional silencing was localized further upstream (between positions -332 and -165). The results suggest that TSG6 gene expression is regulated by an interplay of positively and negatively acting transactivating factors.
Lee
T H
TH
Department of Microbiology, New York University Medical Center, New York 10016.
Klampfer
L
L
Shows
T B
TB
Vilcek
J
J
D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D015815:Cell Adhesion Molecules / Q000235:genetics* / Q000378:metabolism; D002460:Cell Line; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics; D002889:Chromosomes, Human, Pair 2; D003001:Cloning, Molecular; D004247:DNA; D005347:Fibroblasts; D005786:Gene Expression Regulation; D006367:HeLa Cells; D006801:Humans; D006820:Hyaluronic Acid / Q000378:metabolism*; D006822:Hybrid Cells; D007375:Interleukin-1 / Q000502:physiology*; D051379:Mice; D008969:Molecular Sequence Data; D011485:Protein Binding; D014158:Transcription, Genetic / Q000187:drug effects; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D015815:Cell Adhesion Molecules; D007375:Interleukin-1; C072273:TNFAIP6 protein, human; C513057:Tnfaip6 protein, mouse; D014409:Tumor Necrosis Factor-alpha; D006820:Hyaluronic Acid; D004247:DNA; D015500:Chloramphenicol O-Acetyltransferase