Interleukin 4 activates a signal transducer and activator of transcription (Stat) protein which interacts with an interferon-gamma activation site-like sequence upstream of the I epsilon exon in a human B cell line. Evidence for the involvement of Janus kinase 3 and interleukin-4 Stat.

Abstract

Germ line CQ transcripts can be induced by 1L-4 in the human B cell line, BL-2. Utilizing a IFN-y activation sitelike DNA sequence element located upstream of the L exon, we demonstrated by gel mobility shift assays that IL-4 induced a binding activity in the cytosol and nucleus of BL-2 cells. This factor was designated 1L4 NAF (IL-4-induced nuclear-activating factors) and was identified as a tyrosine phosphoprotein, which translocates from the cytosol to the nucleus upon 11-4 treatment. Because these are the characteristics of a signal transducer and activator of transcription (Stat) protein, we determined whether antibodies to Stat proteins will interfere with gel mobility shift and found that antibodies to 11-4 Stat, also known as Stat6, but not antibodies to other Stat proteins, interfere with the formation of the IL-4 NAF complex. Congruous with the involvement of a Stat protein, 1L-4 induced robust Janus kinase 3 (JAK3) activity in BL-2 cells. Cotransfection of JAK3 with 11-4 Stat into COS-7 cells produced an intracellular activity which bound the same IFN-y activation site-like sequence and comigrated with 1L-4 NAF in electrophoretic mobility shift assay. These results show that 1L-4 NAF is 11-4 Stat, which is activated by JAK3 in response to 1L-4 receptor engagement. (J. Clin. Invest. 1995. 96:907-914.)

Stat6 Activation Is Essential for Interleukin-4 Induction of P-Selectin Transcription in Human Umbilical Vein Endothelial Cells

“…Site 1 and 2 sequences were from the P-selectin promoter, and the I⑀ core Stat6 sequence (italicized) was from the immunoglobulin ⑀ (I⑀) promoter that was previously shown to bind Stat6. 25 The mut sequence contained mutations in the site 1 core sequence that rendered it unable to bind Stat6 (data not shown). The ␤-cas sequence is the interferon-␥ activation site-like sequence (GAS) element from the ␤-casein promoter, which binds Stat5 26 and acts as a general STAT-binding site (Y.K-G. et al, unpublished observations, 1998, and Reference 27).…”

“…First, the binding was completely abolished by the addition of a cold competitor oligonucleotide (denoted I⑀) containing the Stat6-binding site of the I⑀ promoter, which had previously been demonstrated to efficiently bind Stat6. 25 In contrast, an oligonucleotide probe with a mutation in the Stat6 consensus sequence (denoted mut) was unable to compete for binding to either site 1 or site 2 probes even when added at 100-fold molar excess. This finding suggests that the IL-4 -inducible factor was specifically binding to both of the canonical Stat6 sequences of the P-selectin promoter.…”

“…Major transcription start sites 28 are denoted by downward arrowheads, and ϩ1 in the sequence is the first nt of the translation initiation codon ATG. 25 and mut, the P-selectin promoter site 1 sequence with a mutation that renders it unable to bind Stat6 (see Methods for actual sequences). Both competitors were used at a 100-fold molar excess.…”

IL-4 and interferon gamma regulate expression of inducible nitric oxide synthase in chronic lymphocytic leukemia cells

“…IL-4 has also been shown to induce transcription factor STAT6 binding to a GAS element in the monocytic cell line THP-1 55,58 and in the B cell line BL-2. 59 In B-CLL cells, STAT-1 is activated 60 and STAT-6 nuclear translocation is induced by IL-4. 61 Therefore, taken together, these studies suggest that constitutive and cytokine-induced NOS2 expression in B-CLL cells may be regulated by STAT-1, STAT-6 and NOS2 GAS promoter elements at the transcriptional level.…”

Inhibition of Interleukin-4- and CD40-induced IgE Germline Gene Promoter Activity by 2′-Aminoethoxy-modified Triplex-forming Oligonucleotides

“…Latent STAT6 is activated in the cytoplasm by tyrosine phosphorylation. In its activated state, it can dimerize, translocate to the nucleus, and bind to a specific DNA sequence in the regulatory region of the IgE germline gene (20). There it functionally interacts with other constitutively bound factors such as C/EBP (21), PU.1 (22), and two different sets of NF-B/Rel family members (23)(24)(25).…”