HB Shu, WH Hu and H Johnson National Jewish Medical and Research Center, University of Colorado Health Sciences Center, Department of Immunology, Denver 80206, USA. shuh@njc.org Members of the tumor necrosis factor (TNF) family play important roles in modulation of immune responses. We describe the identification and cloning of a novel TNF family member that has been designated as TALL-1. TALL-1 is a 285-amino acid type II transmembrane protein. Its carboxy terminus shares approximately 35% sequence identity with the recently identified APRIL and approximately 20-25% with TNF, FasL, TRAIL, and lymphotoxin-alpha, suggesting that TALL-1 and APRIL belong to a subfamily of the TNF family of ligands. Northern blot analysis suggests that TALL-1 is expressed abundantly in peripheral blood leukocytes and weakly in spleen but is barely detectable in all other tissues examined. Reverse transcriptase-polymerase chain reaction analysis indicates that TALL-1 is specifically expressed in monocytes and macrophages but is undetectable in T and B lymphocytes. Furthermore, TALL-1 expression is dramatically down-regulated by phorbol myristate acetate/ionomycin. Related Articles Editorials : Joost J. Oppenheim The 2005 Dolph Adams awards and the state of the Journal of Leukocyte Biology J Leukoc Biol January 1, 2006 79 : 1 - 3 ; doi: 10.1189/jlb.0805480 Full Text Full Text (PDF) Editorials : Joost J. Oppenheim The 2004 Dolph Adams awards and the state of the Journal of Leukocyte Biology J Leukoc Biol January 1, 2005 77 : 1 - 2 ; doi: 10.1189/jlb.0704431 Full Text Full Text (PDF) Editorials : Joost J. Oppenheim The 2003 Dolph Adams awards and the state of the Journal of Leukocyte Biology J Leukoc Biol January 1, 2004 75 : 1 - 2 ; doi: 10.1189/jlb.1003520 Full Text Full Text (PDF)
/lp/fed-of-american-socs-for-experimental-biology/tall-1-is-a-novel-member-of-the-tnf-family-that-is-down-regulated-by-Vu92TyQ2wk