A novel mouse c-fos intronic promoter that responds to CREB and AP-1 is developmentally regulated in vivo

• Published in: PloS one 2010-06, Vol.5 (6), p.e11235-e11235
• Main Authors: Coulon, Vincent, Chebli, Karim, Cavelier, Patricia, Blanchard, Jean-Marie
• Format: Article
• Language: English
• Subjects: Adults; Analysis; Animals; Base Sequence; beta-Galactosidase - genetics; Binding Sites; Biochemistry, Molecular Biology; Brain; Breastfeeding & lactation; c-Fos protein; c-Jun protein; Calcium; Calcium (intracellular); Cell Biology/Gene Expression; Cell cycle; Cell Line; Central nervous system; Conserved Sequence; Cyclic adenosine monophosphate; Cyclic AMP response element-binding protein; Cyclic AMP Response Element-Binding Protein - metabolism; Developmental Biology/Developmental Molecular Mechanisms; Electrophoretic Mobility Shift Assay; Embryos; Evolution, Molecular; Expression vectors; Female; Fibroblasts; Fos gene; Fos protein; Gene expression; Gene Expression Regulation, Developmental; Genetic engineering; Genetics and Genomics/Genomics; Genomes; Genomics; Humans; Introns - genetics; Kinases; Life Sciences; Luciferases - genetics; Male; Mammary gland; Mesenchyme; Mice; Mice, Transgenic; Molecular Biology/Transcription Initiation and Activation; Molecular Sequence Data; Musculoskeletal system; Organ Specificity; Promoter Regions, Genetic - genetics; Proto-Oncogene Proteins c-fos - genetics; Regulatory sequences; Reporter gene; RNA; RNA, Messenger - genetics; Rodents; Tata box; TATA Box - genetics; Tissue analysis; Transcription activation; Transcription Factor AP-1 - metabolism; Transcription factors; Transgenic animals; Transgenic mice; Xenopus; Zebrafish
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0011235

The c-fos proto-oncogene is an archetype for rapid and integrative transcriptional activation. Innumerable studies have focused on the canonical promoter, located upstream from the transcriptional start site. However, several regulatory sequences have been found in the first intron. Here we describe an extremely conserved region in c-fos first intron that contains a putative TATA box, and functional TRE and CRE sites. This fragment drives reporter gene activation in fibroblasts, which is enhanced by increasing intracellular calcium and cAMP and by cotransfection of CREB or c-Fos/c-Jun expression vectors. We produced transgenic mice expressing a lacZ reporter controlled by the intronic promoter. Lac Z expression of this promoter is restricted to the developing central nervous system (CNS) and the mesenchyme of developing mammary buds in embryos 12.5 days post-conception, and to brain tissue in adults. RT-QPCR analysis of tissue mRNA, including the anlage of the mammary gland and the CNS, confirms the existence of a novel, nested mRNA initiated in the first intron. Our results provide evidence for a novel, developmentally regulated promoter in the first intron of the c-fos gene.