Publications [#174192] of G. Allan Johnson

Papers Published

1. MD Stewart, Y Choi, GA Johnson, LY Yu-Lee, FW Bazer, TE Spencer, Roles of Stat1, Stat2, and interferon regulatory factor-9 (IRF-9) in interferon tau regulation of IRF-1., Biology of reproduction, vol. 66 no. 2 (February, 2002), pp. 393-400, ISSN 0006-3363
   (last updated on 2010/04/30)

   Abstract:
   Interferon tau (IFNtau) is the pregnancy recognition signal produced by the conceptus trophectoderm and acts in a paracine manner on the ovine endometrium to increase expression of IFN-stimulated genes primarily in the stroma and deep glandular epithelium, including IFN regulatory factor-1 (IRF-1). The roles of Stat1, Stat2, and IRF-9 in IFNtau regulation of IRF-1 expression were determined using human stromal fibroblasts lacking specific IFN signaling components or complemented with specific Stat1 mutants. In parental (2fTGH) cells treated with IFNtau, Stat1alpha/beta was tyrosine phosphorylated by 15 min, and IRF-1 mRNA and protein increased from 0 to 6 h, was maximal at 6 h, and decreased to 24 h. In contrast, IFNtau did not affect IRF-1 expression in Stat1- and Stat2-deficient cells or in Stat1-deficient cells complemented with Stat1 Y701Q or Stat1 R602L mutants. In Stat1-deficient cells complemented with the Stat1 S727A mutant, Stat1alpha, or Stat1beta and treated with IFNtau, IRF-1 increased from 0 to 6 h, was maximal at 6 h, and decreased thereafter. In IRF-9-deficient cells stimulated with IFNtau, IRF-1 increased from 0 to 6 h but did not exhibit the sharp decline from 6 to 12 h observed in other cells. Collectively, results indicate that IFNtau effect on IRF-1 expression is primarily regulated by tyrosine-phosphorylated Stat1alpha or Stat1beta dimers, whereas the decline of IRF-1 after 6 h of IFNtau treatment is regulated by IRF-9.

   Keywords:
   Blotting, Western • Cell Line • Cells, Cultured • DNA-Binding Proteins • Fibroblasts • Humans • Indicators and Reagents • Interferon Regulatory Factor-1 • Interferon Type I • Interferon-Stimulated Gene Factor 3 • Interferon-Stimulated Gene Factor 3, gamma Subunit • Phosphoproteins • Phosphorylation • Pregnancy Proteins • RNA, Messenger • Reverse Transcriptase Polymerase Chain Reaction • STAT1 Transcription Factor • STAT2 Transcription Factor • Signal Transduction • Trans-Activators • Transcription Factors • Tyrosine • biosynthesis • genetics • metabolism • physiology • physiology*