Kautz B, Kakar R, David E, Eklund E A
Department of Medicine, Northwestern University Medical School and The Robert H. Lurie Comprehensive Cancer Center, Chicago Lakeside Veterans Administration Hospital, Chicago, Illinois 60611, USA.
J Biol Chem. 2001 Oct 12;276(41):37868-78. doi: 10.1074/jbc.M103381200. Epub 2001 Aug 1.
The CYBB and NCF2 genes encode the phagocyte respiratory burst oxidase proteins, gp91PHOX and p67PHOX. Previously, we identified homologous CYBB and NCF2 cis elements that are necessary for lineage-specific transcription during late myeloid differentiation. We determined that these homologous cis elements are activated by PU.1, IRF1, interferon consensus sequence-binding protein (ICSBP), and the CREB-binding protein (CBP). Since expression of PU.1 and ICSBP is lineage-restricted, our investigations identified a mechanism of lineage-specific CYBB and NCF2 transcription. Since PU.1, IRF1, ICSBP, and CBP are expressed in undifferentiated myeloid cells, our investigations did not determine the mechanism of differentiation stage-specific CYBB and NCF2 transcription. In the current investigations, we determine that SHP1 protein-tyrosine phosphatase (SHP1-PTP) inhibits gp91PHOX and p67PHOX expression, in undifferentiated myeloid cell lines, by decreasing interaction of PU.1, IRF1, ICSBP, and CBP with the CYBB and NCF2 genes. We also determine that IRF1 and ICSBP are tyrosine-phosphorylated during interferon gamma differentiation of myeloid cell lines, and we identify IRF1 and ICSBP tyrosine residues that are necessary for CYBB and NCF2 transcription. Therefore, these investigations identify a novel mechanism by which SHP1-PTP antagonizes myeloid differentiation and determine that tyrosine phosphorylation of IRF1 and ICSPB mediates stage-specific transcriptional activation in differentiating myeloid cells.
CYBB和NCF2基因编码吞噬细胞呼吸爆发氧化酶蛋白gp91PHOX和p67PHOX。此前，我们鉴定出同源的CYBB和NCF2顺式元件，它们是晚期髓系分化过程中谱系特异性转录所必需的。我们确定这些同源顺式元件由PU.1、IRF1、干扰素共有序列结合蛋白（ICSBP）和CREB结合蛋白（CBP）激活。由于PU.1和ICSBP的表达具有谱系限制性，我们的研究确定了CYBB和NCF2谱系特异性转录的机制。由于PU.1、IRF1、ICSBP和CBP在未分化的髓系细胞中表达，我们的研究未确定分化阶段特异性CYBB和NCF2转录的机制。在当前的研究中，我们确定SHP1蛋白酪氨酸磷酸酶（SHP1-PTP）通过减少PU.1、IRF1、ICSBP和CBP与CYBB和NCF2基因的相互作用，在未分化的髓系细胞系中抑制gp91PHOX和p67PHOX的表达。我们还确定IRF1和ICSBP在髓系细胞系的干扰素γ分化过程中发生酪氨酸磷酸化，并且我们鉴定出CYBB和NCF2转录所必需的IRF1和ICSBP酪氨酸残基。因此，这些研究确定了一种SHP1-PTP拮抗髓系分化的新机制，并确定IRF1和ICSPB的酪氨酸磷酸化介导了分化中的髓系细胞的阶段特异性转录激活。
