title: Identification and implantation stage-specific expression of an interferon-alpha-regulated gene in human and rat endometrium.
abstract: Implantation of the developing blastocyst is regulated by multiple effectors, such as steroid hormones, growth factors, and cytokines. To understand how these diverse signaling pathways interact to modulate uterine gene expression, we employed a gene expression screen technique to identify the molecules that are induced in the periimplantation rat uterus. Here we report the isolation of a complementary DNA representing a novel gene, interferon-regulated gene 1 (IRG1). This gene exhibits significant homology to interferon (IFN)-alpha/beta-inducible human genes p27 and 6-16, indicating that these genes may belong to the same family. Consistent with this finding, expression of IRG1 messenger RNA (mRNA) in rat uterus increased about 20-fold in response to IFNalpha. Uterine expression of IRG1 was also stimulated by estrogen and was partially inhibited by an antiestrogen, ICI 182,780. In pregnant rats, IRG1 expression was high on day 1, but declined on days 2 and 3. The level of IRG1 mRNA again rose transiently on day 4 immediately preceding implantation. In situ hybridization analysis localized the IRG1 mRNA expression in the endometrial epithelium and the surrounding stroma. Interestingly, the expression of p27, which shows high homology to IRG1, was strongly enhanced in human endometrium during the midsecretory phase of the menstrual cycle, overlapping the putative window of implantation. Both IRG1 and p27 mRNAs are therefore induced in the endometrium in an implantation stage-specific manner. We also observed a synergistic interaction between IFNalpha and estrogen receptor signaling pathways that led to maximal induction of p27 mRNA in Ishikawa cells. Although the functional roles of IRG1 and p27 remain unclear, we describe for the first time, identification of a gene family regulated by IFNalpha in both rodent and human uteri. More importantly, our studies reveal that a complex interplay between the steroid hormone and IFN pathways regulates the expression of these genes in the endometrium at the time of implantation.
authors.affiliation: The Population Council and Rockefeller University, New York, NY 10021, USA.
authors.forename: Q
authors.initials: Q
authors.lastname: Li
authors.forename: M
authors.initials: M
authors.lastname: Zhang
authors.forename: S
authors.initials: S
authors.lastname: Kumar
authors.forename: L J
authors.initials: LJ
authors.lastname: Zhu
authors.forename: D
authors.initials: D
authors.lastname: Chen
authors.forename: M K
authors.initials: MK
authors.lastname: Bagchi
authors.forename: I C
authors.initials: IC
authors.lastname: Bagchi
mesh_terms: D000328:Adult; D000595:Amino Acid Sequence; D000818:Animals; D015152:Blotting, Northern; D001943:Breast Neoplasms; D018797:Cell Cycle Proteins; D050760:Cyclin-Dependent Kinase Inhibitor p27; D018076:DNA, Complementary / Q000737:chemistry / Q000302:isolation & purification; D004357:Drug Synergism; D010064:Embryo Implantation; D004717:Endometrium / Q000737:chemistry / Q000378:metabolism*; D004848:Epithelium / Q000737:chemistry; D004958:Estradiol / Q000031:analogs & derivatives* / Q000494:pharmacology; D004967:Estrogens / Q000494:pharmacology; D005260:Female; D000077267:Fulvestrant; D005786:Gene Expression Regulation; D006801:Humans; D016898:Interferon-alpha / Q000494:pharmacology*; D008597:Menstrual Cycle; D008869:Microtubule-Associated Proteins / Q000737:chemistry / Q000235:genetics; D008969:Molecular Sequence Data; D010052:Ovariectomy; D011247:Pregnancy; D011506:Proteins / Q000737:chemistry / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D017385:Sequence Homology; D014162:Transfection; D014407:Tumor Cells, Cultured; D025521:Tumor Suppressor Proteins
chemical_list: C493962:Cdkn1b protein, rat; D018797:Cell Cycle Proteins; D018076:DNA, Complementary; D004967:Estrogens; C428426:IFN-inducible protein p27; C428425:Ifi27 protein, rat; D016898:Interferon-alpha; D008869:Microtubule-Associated Proteins; D011506:Proteins; D012333:RNA, Messenger; D025521:Tumor Suppressor Proteins; D050760:Cyclin-Dependent Kinase Inhibitor p27; D000077267:Fulvestrant; D004958:Estradiol