title: Identification of a functionally distinct truncated BDNF mRNA splice variant and protein in Trachemys scripta elegans.
abstract: Brain-derived neurotrophic factor (BDNF) has a diverse functional role and complex pattern of gene expression. Alternative splicing of mRNA transcripts leads to further diversity of mRNAs and protein isoforms. Here, we describe the regulation of BDNF mRNA transcripts in an in vitro model of eyeblink classical conditioning and a unique transcript that forms a functionally distinct truncated BDNF protein isoform. Nine different mRNA transcripts from the BDNF gene of the pond turtle Trachemys scripta elegans (tBDNF) are selectively regulated during classical conditioning: exon I mRNA transcripts show no change, exon II transcripts are downregulated, while exon III transcripts are upregulated. One unique transcript that codes from exon II, tBDNF2a, contains a 40 base pair deletion in the protein coding exon that generates a truncated tBDNF protein. The truncated transcript and protein are expressed in the naïve untrained state and are fully repressed during conditioning when full-length mature tBDNF is expressed, thereby having an alternate pattern of expression in conditioning. Truncated BDNF is not restricted to turtles as a truncated mRNA splice variant has been described for the human BDNF gene. Further studies are required to determine the ubiquity of truncated BDNF alternative splice variants across species and the mechanisms of regulation and function of this newly recognized BDNF protein.
authors.affiliation: Neuroscience Group, Division of Basic Biomedical Sciences, University of South Dakota Sanford School of Medicine, Vermillion, South Dakota, United States of America.
authors.forename: Ganesh
authors.initials: G
authors.lastname: Ambigapathy
authors.forename: Zhaoqing
authors.initials: Z
authors.lastname: Zheng
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.forename: Joyce
authors.initials: J
authors.lastname: Keifer
mesh_terms: D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D019208:Brain-Derived Neurotrophic Factor / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D005786:Gene Expression Regulation; D006801:Humans; D008969:Molecular Sequence Data; D009474:Neurons / Q000166:cytology; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D030162:Reptilian Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D017384:Sequence Deletion; D015398:Signal Transduction; D014426:Turtles
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D020033:Protein Isoforms; D012333:RNA, Messenger; D030162:Reptilian Proteins