title: Tissue-specific and neural activity-regulated expression of human BDNF gene in BAC transgenic mice.
abstract: BACKGROUND
  Brain-derived neurotrophic factor (BDNF) is a small secreted protein that has important roles in the developing and adult nervous system. Altered expression or changes in the regulation of the BDNF gene have been implicated in a variety of human nervous system disorders. Although regulation of the rodent BDNF gene has been extensively investigated, in vivo studies regarding the human BDNF gene are largely limited to postmortem analysis. Bacterial artificial chromosome (BAC) transgenic mice harboring the human BDNF gene and its regulatory flanking sequences constitute a useful tool for studying human BDNF gene regulation and for identification of therapeutic compounds modulating BDNF expression.
  
  
  RESULTS
  In this study we have generated and analyzed BAC transgenic mice carrying 168 kb of the human BDNF locus modified such that BDNF coding sequence was replaced with the sequence of a fusion protein consisting of N-terminal BDNF and the enhanced green fluorescent protein (EGFP). The human BDNF-BAC construct containing all BDNF 5' exons preceded by different promoters recapitulated the expression of endogenous BDNF mRNA in the brain and several non-neural tissues of transgenic mice. All different 5' exon-specific BDNF-EGFP alternative transcripts were expressed from the transgenic human BDNF-BAC construct, resembling the expression of endogenous BDNF. Furthermore, BDNF-EGFP mRNA was induced upon treatment with kainic acid in a promotor-specific manner, similarly to that of the endogenous mouse BDNF mRNA.
  
  
  CONCLUSIONS
  Genomic region covering 67 kb of human BDNF gene, 84 kb of upstream and 17 kb of downstream sequences is sufficient to drive tissue-specific and kainic acid-induced expression of the reporter gene in transgenic mice. The pattern of expression of the transgene is highly similar to BDNF gene expression in mouse and human. This is the first study to show that human BDNF gene is regulated by neural activity.
authors: Department of Gene Technology, Tallinn University of Technology, Akadeemia tee 15, 12618 Tallinn, Estonia. indrek.koppel@ttu.ee
authors: Indrek
authors: I
authors: Koppel
authors: Tamara
authors: T
authors: Aid-Pavlidis
authors: Kaur
authors: K
authors: Jaanson
authors: Mari
authors: M
authors: Sepp
authors: Priit
authors: P
authors: Pruunsild
authors: Kaia
authors: K
authors: Palm
authors: Tõnis
authors: T
authors: Timmusk
mesh_terms: D000818:Animals; D001921:Brain / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D019208:Brain-Derived Neurotrophic Factor / Q000235:genetics* / Q000378:metabolism*; D022202:Chromosomes, Artificial, Bacterial; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects / Q000235:genetics*; D049452:Green Fluorescent Proteins / Q000235:genetics; D006801:Humans; D007608:Kainic Acid / Q000494:pharmacology; D051379:Mice; D008822:Mice, Transgenic; D009474:Neurons / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D018690:Excitatory Amino Acid Agonists; D012333:RNA, Messenger; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D007608:Kainic Acid