title: The interferon consensus sequence-binding protein (ICSBP/IRF8) represses PTPN13 gene transcription in differentiating myeloid cells.
abstract: The interferon consensus sequence-binding protein (ICSBP/IRF8) is an interferon regulatory factor that is expressed in myeloid and B-cells. ICSBP-deficient mice develop a myeloproliferative disorder characterized by cytokine hypersensitivity and apoptosis resistance. To identify ICSBP target genes involved in these effects, we screened a CpG island microarray with chromatin that co-immunoprecipitated with ICSBP from myeloid cells. Using this technique, we identified PTPN13 as an ICSBP target gene. PTPN13 encodes Fas-associated phosphatase 1 (Fap-1), a ubiquitously expressed protein-tyrosine phosphatase. This was of interest because interaction of Fap-1 with Fas results in Fas dephosphorylation and inhibition of Fas-induced apoptosis. In this study, we found that ICSBP influenced Fas-induced apoptosis in a Fap-1-dependent manner. We also found that ICSBP interacted with a cis element in the proximal PTPN13 promoter and repressed transcription. This interaction increased during myeloid differentiation and was regulated by phosphorylation of conserved tyrosine residues in the interferon regulatory factor domain of ICSBP. ICSBP deficiency was present in human myeloid malignancies, including chronic myeloid leukemia. Therefore, these studies identified a mechanism for increased survival of mature myeloid cells in the ICSBP-deficient murine model and in human myeloid malignancies with decreased ICSBP expression.
authors.affiliation: The Feinberg School of Medicine and The Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, Illinois 60611, USA.
authors.forename: Weiqi
authors.initials: W
authors.lastname: Huang
authors.forename: Chunliu
authors.initials: C
authors.lastname: Zhu
authors.forename: Hao
authors.initials: H
authors.lastname: Wang
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Horvath
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Eklund
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics; D001402:B-Lymphocytes / Q000378:metabolism; D002454:Cell Differentiation / Q000235:genetics; D018899:CpG Islands / Q000235:genetics; D020869:Gene Expression Profiling; D015971:Gene Expression Regulation, Enzymologic / Q000235:genetics; D006801:Humans; D050835:Interferon Regulatory Factors / Q000235:genetics / Q000378:metabolism*; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000235:genetics / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D022423:Myeloid Cells / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D054595:Protein Tyrosine Phosphatase, Non-Receptor Type 13 / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism*; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic / Q000235:genetics; D020298:U937 Cells; D019014:fas Receptor / Q000235:genetics / Q000378:metabolism; D000099185:Interferon Regulatory Factor-8
chemical_list: D050835:Interferon Regulatory Factors; D054595:Protein Tyrosine Phosphatase, Non-Receptor Type 13; D012097:Repressor Proteins; D019014:fas Receptor; D000099185:Interferon Regulatory Factor-8; C516742:PTPN13 protein, human; C516743:Ptpn13 protein, mouse