title: Intronic DNA elements regulate androgen-dependent expression of the murine Nkx3.1 gene.
abstract: Nkx3.1 is a well-conserved homeobox gene that is involved in development, differentiation and maintenance of prostate epithelial cells. Nkx3.1 expression is induced by androgen in prostate epithelia and, as such, our interest is to understand the mechanism(s) for this androgen-dependent expression in normal epithelial cells. In this report, we show that the region of DNA sequence 2.7 kilobases in front of the mouse Nkx3.1 gene drives enhanced transcription in prostate epithelia cells; however, this segment was not capable of androgen-directed regulation. Among the multiple, potential androgen response elements (AREs) identified by scanning sequences near and within the gene, two sequences within the intron of the murine Nkx3.1 gene were demonstrated to confer androgen-dependent transcription in reporter gene transfection experiments. Each of the elements, termed ARE A and ARE B, contained a 6-base pair core sequence, TGTTCT, that has been described as an androgen receptor half-site binding sequence, separated by 498 base pairs of DNA. Both of the intronic half-sites bind activated androgen receptor from a variety of sources, albeit with different apparent affinities. This region of the Nkx3.1 gene demonstrates a high degree of conservation among diverse species and mutagenesis experiments demonstrated that both elements are required for androgen stimulation. Taken together, our study shows that androgen-dependent transcription of the mouse Nkx3.1 gene is conferred through a noncanonical element within the intron of the gene.
authors.affiliation: Department of Systems Biology and Translational Medicine, College of Medicine, Texas A&M Health Science Center, College Station, TX 77843-1114, USA.
authors.forename: Chinatsu
authors.initials: C
authors.lastname: Kojima
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Warren E
authors.initials: WE
authors.lastname: Zimmer
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D000728:Androgens / Q000494:pharmacology*; D000818:Animals; D019556:COS Cells; D045744:Cell Line, Tumor; D002522:Chlorocebus aethiops; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D018398:Homeodomain Proteins / Q000235:genetics*; D006801:Humans; D007438:Introns / Q000235:genetics*; D008297:Male; D051379:Mice; D011471:Prostatic Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D011485:Protein Binding; D011944:Receptors, Androgen / Q000378:metabolism; D050436:Regulatory Elements, Transcriptional / Q000502:physiology*; D020218:Response Elements / Q000187:drug effects / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics*; D015533:Transcriptional Activation / Q000187:drug effects / Q000502:physiology
chemical_list: D000728:Androgens; D018398:Homeodomain Proteins; C102837:Nkx3-1 protein, mouse; D011944:Receptors, Androgen; D014157:Transcription Factors