Distinct requirements for the naturally occurring splice forms Stat4alpha and Stat4beta in IL-12 responses.
Signal transducer and activator of transcription (Stat)4 is a signaling molecule required for normal responses to interleukin-12 (IL-12) and is critically involved in inflammatory responses. We have isolated an alternatively spliced isoform of Stat4, termed Stat4beta, which lacks 44 amino acids at the C-terminus, encompassing the putative transcriptional activation domain. To assess the in vivo roles of these Stat4 isoforms, we generated transgenic Stat4-deficient mice expressing Stat4alpha or Stat4beta. Our results indicate that T-cell-specific expression of Stat4alpha or Stat4beta can mediate many aspects of IL-12 signaling including the differentiation of Th1 cells. However, Stat4alpha is required for normal levels of IL-12-induced interferon-gamma production from Th1 cells. Microarray analysis identified 98 genes induced by both Stat4 isoforms, 32 genes induced only by Stat4alpha and 29 genes induced only by Stat4beta. Some induced genes correlate with specific functions including the ability of Stat4beta, but not Stat4alpha, to mediate IL-12-stimulated proliferation. Thus, Stat4alpha and Stat4beta have distinct roles in mediating responses to IL-12.
Hoey
Timothy
T
Tularik, Inc., South San Francisco, CA 94080, USA.
Zhang
Shangming
S
Schmidt
Nathan
N
Yu
Qing
Q
Ramchandani
Shyam
S
Xu
Xiang
X
Naeger
Lisa K
LK
Sun
Ya-Lin
YL
Kaplan
Mark H
MH
D000276:Adjuvants, Immunologic / Q000494:pharmacology; D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000378:metabolism; D001483:Base Sequence; D019556:COS Cells; D002454:Cell Differentiation; D002455:Cell Division; D002522:Chlorocebus aethiops; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D018664:Interleukin-12 / Q000378:metabolism / Q000494:pharmacology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D020033:Protein Isoforms / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D050797:STAT4 Transcription Factor; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000378:metabolism; D018417:Th1 Cells / Q000166:cytology / Q000502:physiology; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*
D000276:Adjuvants, Immunologic; D000911:Antibodies, Monoclonal; D004268:DNA-Binding Proteins; D020033:Protein Isoforms; D012333:RNA, Messenger; D050797:STAT4 Transcription Factor; C494091:Stat4 protein, mouse; D015534:Trans-Activators; D018664:Interleukin-12