Glutamate regulates kainate-binding protein expression in cultured chick Bergmann glia through an activator protein-1 binding site.
The expression of the chick kainate-binding protein, a member of the ionotropic glutamate receptor family, is restricted to the cerebellum, specifically to Bergmann glia. Glutamate induces a membrane to nuclei signaling involved in gene expression regulation. Exposure of cultured chick Bergmann glia cells to glutamate leads to an increase in kainate binding protein and mRNA levels, suggesting a transcriptional level of regulation. The 5' proximal region of the chick kainate binding gene was cloned and transfected 4into Bergmann glia cells. Three main regulatory regions could be defined, a minimal promoter region, a negative regulatory region, and interestingly, a glutamate-responsive element. Deletion of this element abolishes the agonist effect. Moreover, electrophoretic mobility shift assays, cotransfection experiments, and site-directed mutagenesis clearly suggest that the glutamate effect is mediated through an AP-1 site by a Fos/Jun heterodimer. The present results favor the notion of a functional role of kainate-binding protein in glutamatergic cerebellar neurotransmission.
Aguirre
A
A
Departamento de Genética y Biologia Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Apartado Postal 14-740, México D.F. 07000, México.
López
T
T
López-Bayghen
E
E
Ortega
A
A
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D015152:Blotting, Northern; D015153:Blotting, Western; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D002531:Cerebellum / Q000378:metabolism; D002642:Chick Embryo; D015500:Chloramphenicol O-Acetyltransferase / Q000378:metabolism; D003001:Cloning, Molecular; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D005786:Gene Expression Regulation; D018698:Glutamic Acid / Q000502:physiology*; D008954:Models, Biological; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009457:Neuroglia / Q000378:metabolism*; D010957:Plasmids / Q000378:metabolism; D011401:Promoter Regions, Genetic; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D017470:Receptors, Glutamate / Q000096:biosynthesis* / Q000235:genetics; D018092:Kainic Acid Receptors / Q000096:biosynthesis* / Q000235:genetics*; D020218:Response Elements; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D018808:Transcription Factor AP-1 / Q000737:chemistry* / Q000378:metabolism*; D014158:Transcription, Genetic; D014162:Transfection; D015854:Up-Regulation
D015500:Chloramphenicol O-Acetyltransferase; D018698:Glutamic Acid; D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; D012333:RNA, Messenger; D017470:Receptors, Glutamate; D018092:Kainic Acid Receptors; D018808:Transcription Factor AP-1