Molecular Identification of the 62 kd Form of Glutamic Acid Decarboxylase from the Mouse

Authors

  • Z. Katarova,

    Corresponding author
    1. Department of Biology, Princeton University, Princeton, NJ and Department of Neurosciences, Roche Institute of Molecular Biology, Nutley, NJ 07110, USA
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  • G. Szabo,

    Corresponding author
    1. Department of Biology, Princeton University, Princeton, NJ and Department of Neurosciences, Roche Institute of Molecular Biology, Nutley, NJ 07110, USA
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  • E. Mugnaini,

    1. Laboratory of Neuromorphology, University of Connecticut, Storrs, CT 06269-4154, USA
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  • R. J. Greenspan

    Corresponding author
    1. Department of Biology, Princeton University, Princeton, NJ and Department of Neurosciences, Roche Institute of Molecular Biology, Nutley, NJ 07110, USA
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Correspondence to: Z. Katarova and G. Szabo, Biological Research Center of the Hungarian Academy of Sciences, H-6701 Szeged, PO Box 521, Hungary

All reprint requests and all correspondence other than European to: R. J. Greenspan, Department of Neurosciences, Roche Institute of Molecular Biology, Nutley, NJ 07110, USA

Abstract

A series of overlapping clones coding for L-glutamic acid decarboxylase was purified from a mouse brain cDNA library, the longest of which contains a 1869 bp open reading frame and 913 bp of non-coding sequence. By comparison with the corresponding sequences from the mouse genome, it was determined that the first methionine in the longest cDNA represents the initiation codon. Expression of this cDNA in eukaryotic cells produces a 62 kd protein that is recognized by antiserum against rat GAD and which displays GAD activity commensurate with the amount of protein produced. Antibodies raised against the purified product of this cDNA recognize a 62 kd protein from mouse brain on immunoblots, specifically stain GABA-ergic neurons in brain sections, and are capable of immunoprecipitating most GAD activity from mouse brain extracts. These results provide the first definitive identification of a cDNA coding for the larger of two forms of GAD in mouse brain, and suggest that the two forms are closely related.

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