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. 1990 Nov;87(22):8771–8775. doi: 10.1073/pnas.87.22.8771

Developmentally regulated expression of an exon containing a stop codon in the gene for glutamic acid decarboxylase.

R W Bond 1, R J Wyborski 1, D I Gottlieb 1
PMCID: PMC55041  PMID: 2247446

Abstract

In the adult rat brain, the gene for glutamic acid decarboxylase (GAD; L-glutamate 1-carboxy-lyase, EC 4.1.1.15) is expressed predominantly as a 3.7-kilobase transcript. Earlier data showed that embryonic brain expresses an RNA transcript distinct from the adult form; however, the exact structure of this form was not elucidated. Here, transcripts expressed in the embryonic but not the adult brain were cloned and analyzed. These transcripts include an exon not expressed in the adult inserted into coding sequence. The embryonic exon contains a stop codon that is in-frame with the coding sequence. The exon is found in genomic DNA within the GAD gene where it is flanked by introns with conventional splice sites. On the basis of these structural data, we propose the hypothesis that, early in brain development, transcripts encoding a truncated form of GAD are expressed. The deduced protein cannot function as a decarboxylase because the stop codon in the embryonic exon occurs upstream of the binding site for pyridoxal phosphate, an essential cofactor. Thus, alternative splicing plays a crucial role in the pathway leading to the development of functional GABAergic neurons. The central nervous system-derived cell lines B65 and C6 express a mixture of the adult and embryonic forms of GAD mRNA. They therefore are useful clonal models of central nervous system cells in the early phases of differentiation.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Amara S. G., Jonas V., Rosenfeld M. G., Ong E. S., Evans R. M. Alternative RNA processing in calcitonin gene expression generates mRNAs encoding different polypeptide products. Nature. 1982 Jul 15;298(5871):240–244. doi: 10.1038/298240a0. [DOI] [PubMed] [Google Scholar]
  2. Bell L. R., Maine E. M., Schedl P., Cline T. W. Sex-lethal, a Drosophila sex determination switch gene, exhibits sex-specific RNA splicing and sequence similarity to RNA binding proteins. Cell. 1988 Dec 23;55(6):1037–1046. doi: 10.1016/0092-8674(88)90248-6. [DOI] [PubMed] [Google Scholar]
  3. Bond R. W., Jansen K. R., Gottlieb D. I. Pattern of expression of glutamic acid decarboxylase mRNA in the developing rat brain. Proc Natl Acad Sci U S A. 1988 May;85(9):3231–3234. doi: 10.1073/pnas.85.9.3231. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Chesselet M. F., Weiss L., Wuenschell C., Tobin A. J., Affolter H. U. Comparative distribution of mRNAs for glutamic acid decarboxylase, tyrosine hydroxylase, and tachykinins in the basal ganglia: an in situ hybridization study in the rodent brain. J Comp Neurol. 1987 Aug 1;262(1):125–140. doi: 10.1002/cne.902620110. [DOI] [PubMed] [Google Scholar]
  5. Gower H. J., Barton C. H., Elsom V. L., Thompson J., Moore S. E., Dickson G., Walsh F. S. Alternative splicing generates a secreted form of N-CAM in muscle and brain. Cell. 1988 Dec 23;55(6):955–964. doi: 10.1016/0092-8674(88)90241-3. [DOI] [PubMed] [Google Scholar]
  6. Kobayashi Y., Kaufman D. L., Tobin A. J. Glutamic acid decarboxylase cDNA: nucleotide sequence encoding an enzymatically active fusion protein. J Neurosci. 1987 Sep;7(9):2768–2772. doi: 10.1523/JNEUROSCI.07-09-02768.1987. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Levine J. M., Beasley L., Stallcup W. B. The D1.1 antigen: a cell surface marker for germinal cells of the central nervous system. J Neurosci. 1984 Mar;4(3):820–831. doi: 10.1523/JNEUROSCI.04-03-00820.1984. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. O'Malley K. L., Anhalt M. J., Martin B. M., Kelsoe J. R., Winfield S. L., Ginns E. I. Isolation and characterization of the human tyrosine hydroxylase gene: identification of 5' alternative splice sites responsible for multiple mRNAs. Biochemistry. 1987 Nov 3;26(22):6910–6914. doi: 10.1021/bi00396a007. [DOI] [PubMed] [Google Scholar]
  9. Sanger F., Nicklen S., Coulson A. R. DNA sequencing with chain-terminating inhibitors. Proc Natl Acad Sci U S A. 1977 Dec;74(12):5463–5467. doi: 10.1073/pnas.74.12.5463. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Schubert D., Heinemann S., Carlisle W., Tarikas H., Kimes B., Patrick J., Steinbach J. H., Culp W., Brandt B. L. Clonal cell lines from the rat central nervous system. Nature. 1974 May 17;249(454):224–227. doi: 10.1038/249224a0. [DOI] [PubMed] [Google Scholar]
  11. Tindall K. R., Kunkel T. A. Fidelity of DNA synthesis by the Thermus aquaticus DNA polymerase. Biochemistry. 1988 Aug 9;27(16):6008–6013. doi: 10.1021/bi00416a027. [DOI] [PubMed] [Google Scholar]
  12. Wuenschell C. W., Fisher R. S., Kaufman D. L., Tobin A. J. In situ hybridization to localize mRNA encoding the neurotransmitter synthetic enzyme glutamate decarboxylase in mouse cerebellum. Proc Natl Acad Sci U S A. 1986 Aug;83(16):6193–6197. doi: 10.1073/pnas.83.16.6193. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Wyborski R. J., Bond R. W., Gottlieb D. I. Characterization of a cDNA coding for rat glutamic acid decarboxylase. Brain Res Mol Brain Res. 1990 Aug;8(3):193–198. doi: 10.1016/0169-328x(90)90016-7. [DOI] [PubMed] [Google Scholar]

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