title: Progesterone regulation of RUSH/SMARCA3/HLTF includes DNA looping.
abstract: RUSH/SMARCA3 (SWI/SNF-related matrix-associated actin-dependent regulator of chromatin subfamily A, member 3) is capable of sequence-selective DNA binding and ATP-dependent DNA unwinding. In rabbit uterine epithelial cells, RUSH-1alpha (113 kDa) is the progesterone-dependent splice variant and RUSH-1beta (95 kDa) is the oestrogen-dependent splice variant. Rabbit RUSH/SMARCA3 mRNA is primarily regulated at the proximal promoter (-162/+90) via a PRE (progesterone-response element) half-site/overlapping Y-box domain (-38/-26) and two Sp (specificity protein) 3 sites centred at -128 and -58. We investigated hormone regulation by exploring binding of transcription factors to a putative RUSH/SMARCA3 site (-616/-611) and the distal Sp3 (-131/-126) site. In response to progesterone, RUSH-1alpha binds the RUSH site and the Sp3 site becomes a functional binding site for Egr-1 (early growth-response gene product 1)/Sp (specificity protein)1/3/MAZ (Myc-associated zinc-finger protein)/MZF1 (myeloid zinc finger 1)/c-Rel. TransSignal TF-TF Interaction Arrays, supershift assays and ChIP (chromatin immunoprecipitation) analyses confirmed strong physical interactions between RUSH and Egr-1/c-Rel. Higher-order long-range interactions between RUSH and the Egr-1/c-Rel derivative of the anisotropic flexibility of the intervening DNA sequence were shown with 3C (chromosome conformation capture) assays. Transient transfection assays with mutant constructs showed the co-operative interaction between RUSH and Egr-1 mediates repression by c-Rel. Thus DNA-bound RUSH/SMARCA3 communicates with its own proximal promoter by looping the intervening DNA. Moreover, progesterone-dependent DNA looping is an adjunct to progesterone induction of the RUSH/SMARCA3 gene because the availability of RUSH isoforms and relevant binding partners is progesterone-regulated.
authors.affiliation: Department of Cell Biology & Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA. Beverly.Chilton@ttuhsc.edu
authors.forename: Beverly S
authors.initials: BS
authors.lastname: Chilton
authors.forename: Aveline
authors.initials: A
authors.lastname: Hewetson
mesh_terms: D017398:Alternative Splicing / Q000235:genetics; D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism; D004247:DNA / Q000737:chemistry* / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D009690:Nucleic Acid Conformation; D011374:Progesterone / Q000494:pharmacology*; D014157:Transcription Factors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; D014157:Transcription Factors; D011374:Progesterone; D004247:DNA