title: Expression of endogenous NMDAR1 transcripts without receptor protein suggests post-transcriptional control in PC12 cells.
abstract: Expression of RNA for the NMDAR1 subunit of the N-methyl-D-aspartate receptor was detected by Northern hybridization in both nerve growth factor-differentiated and undifferentiated rat pheochromocytoma (PC12) cells. The NMDA receptor type 1 (NMDAR1) message in PC12 cells was similar in size to that expressed in hippocampal neurons. PC12 cell cDNAs that were amplified by polymerase chain reaction with primers flanking the coding region of NMDAR1 corresponded to the NMDAR1 splice variant NMDA receptor type 1 isoform C (NMDAR1C). Using calcium imaging or patch-clamp recording, no functional NMDA-gated ion channels were found in PC12 cells. A monoclonal antibody against NMDAR1 was developed in order to investigate whether or not NMDAR1 protein was present in PC12 cells. Only trace amounts of NMDAR1 protein were found in native PC12 cells. However, expression of NMDAR1 protein was detected in PC12 cells that were transfected with an expression vector containing an NMDAR1C clone under control of a cytomegalovirus promoter. These findings suggest that the expression of NMDAR1 protein in PC12 cells may be controlled by post-transcriptional mechanisms. The PC12 cell line may serve as a model system for the study of the transcriptional, post-transcriptional, and translational regulation of NMDAR1. Furthermore, the presence of NMDAR1 RNA in a particular cell type may not necessarily indicate expression of NMDAR1 protein.
authors.affiliation: Laboratory of Cellular and Molecular Neuroscience, Department of Neurology, Children's Hospital, Boston, Massachusetts 02115
authors.forename: N J
authors.initials: NJ
authors.lastname: Sucher
authors.affiliation: Molecular Neurobiology Laboratory, the Salk Institute, La Jolla, California 92037
authors.forename: N
authors.initials: N
authors.lastname: Brose
authors.affiliation: Department of Genetics, Boston, Massachusetts 02115
authors.forename: D L
authors.initials: DL
authors.lastname: Deitcher
authors.affiliation: Laboratory of Cellular and Molecular Neuroscience, Department of Neurology, Children's Hospital, Boston, Massachusetts 02115|Program in Neuroscience, Boston, Massachusetts 02115
authors.forename: M
authors.initials: M
authors.lastname: Awobuluyi
authors.affiliation: Molecular Neurobiology Laboratory, the Salk Institute, La Jolla, California 92037
authors.forename: G P
authors.initials: GP
authors.lastname: Gasic
authors.affiliation: Department of Microbiology and Molecular Genetics, Boston, Massachusetts 02115
authors.forename: H
authors.initials: H
authors.lastname: Bading
authors.affiliation: Department of Genetics, Boston, Massachusetts 02115|Program in Neuroscience, Boston, Massachusetts 02115
authors.forename: C L
authors.initials: CL
authors.lastname: Cepko
authors.affiliation: Department of Microbiology and Molecular Genetics, Boston, Massachusetts 02115|Howard Hughes Medical Institute, Boyer Center for Molecular Medicine, Yale University School of Medicine, New Haven, Connecticut 06510|Departments of Neurology, Beth Israel Hospital, Brigham and Women's Hospital, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02115
authors.forename: M E
authors.initials: ME
authors.lastname: Greenberg
authors.affiliation: Departments of Neurology, Beth Israel Hospital, Brigham and Women's Hospital, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02115
authors.forename: R
authors.initials: R
authors.lastname: Jahn
authors.affiliation: Molecular Neurobiology Laboratory, the Salk Institute, La Jolla, California 92037
authors.forename: S F
authors.initials: SF
authors.lastname: Heinemann
authors.affiliation: Laboratory of Cellular and Molecular Neuroscience, Department of Neurology, Children's Hospital, Boston, Massachusetts 02115|Program in Neuroscience, Boston, Massachusetts 02115|Departments of Neurology, Beth Israel Hospital, Brigham and Women's Hospital, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02115
authors.forename: S A
authors.initials: SA
authors.lastname: Lipton
mesh_terms: D017398:Alternative Splicing; D000818:Animals; D001253:Astrocytes / Q000378:metabolism; D001483:Base Sequence; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D002478:Cells, Cultured; D017931:DNA Primers; D004246:Dimethylphenylpiperazinium Iodide / Q000494:pharmacology; D015870:Gene Expression; D015972:Gene Expression Regulation, Neoplastic; D014644:Genetic Variation; D006624:Hippocampus / Q000378:metabolism; D006801:Humans; D007668:Kidney; D046911:Macromolecular Substances; D008564:Membrane Potentials / Q000187:drug effects; D008969:Molecular Sequence Data; D008970:Molecular Weight; D016202:N-Methylaspartate / Q000494:pharmacology; D009414:Nerve Growth Factors / Q000494:pharmacology; D016716:PC12 Cells; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000302:isolation & purification / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000096:biosynthesis* / Q000235:genetics*; D013570:Synaptic Membranes / Q000378:metabolism; D014158:Transcription, Genetic; D014162:Transfection
chemical_list: D017931:DNA Primers; D046911:Macromolecular Substances; D009414:Nerve Growth Factors; D012333:RNA, Messenger; D016194:Receptors, N-Methyl-D-Aspartate; D004246:Dimethylphenylpiperazinium Iodide; D016202:N-Methylaspartate