Cloning of a novel tumor necrosis factor-alpha-inducible primary response gene that is differentially expressed in development and capillary tube-like formation in vitro.

TNF is a proinflammatory cytokine that has pleiotropic effects on cells and tissues, mediated in large part by alterations in target tissue gene expression. We have used the technique of differential hybridization to identify several primary response genes induced by TNF in human umbilical vein endothelial (HUVE) cells, a cell type that is profoundly activated by cytokine treatment. One of these cDNA, designated B94, detects a rapidly and transiently induced 4-kb transcript in TNF-treated HUVE cells, and this transcript is superinduced in the concomitant presence of cycloheximide. Other proinflammatory stimuli including IL-1 beta and LPS are also able to induce B94 mRNA expression. Nuclear run-on experiments demonstrate that TNF induction of B94 transcript occurs primarily at the level of transcriptional activation. Further, B94 is shown to be a single copy gene that is evolutionarily conserved. The gene is localized to the q32 region of chromosome 14, a region that is often rearranged in lymphoid neoplasms. B94 transcript expression is also found to be regulated during mouse development and in an in vitro model of endothelial capillary tube formation. Developmental regulation occurs most prominently in mouse embryonic liver and kidney, and a second smaller form of B94 transcript is detected in the placenta and testes. B94 and other TNF-responsive transcripts are also induced during capillary tube formation suggesting overlap between genes induced by TNF and those induced during angiogenesis. Sequence analysis of the B94 cDNA reveals an open reading frame encoding a 73-kDa polypeptide that has no homology to any known protein. Polyclonal antisera directed against the carboxyl-terminal portion of the B94 protein immunoprecipitates a protein of the predicted molecular mass both from COS cells transfected with a B94 expression vector and from TNF-treated HUVE cells.