Developmentally‐regulated expression of tissue‐specific splice variant of rat vesicular glutamate transporter 1 in retina and pineal gland

• Published in: Journal of neurochemistry Vol. 99; no. 1; pp. 142 - 153
• Main Authors: Nogami, Haruo, Ogasawara, Kiyomoto, Mimura, Yuka, Mogi, Koichi, Shutoh, Fumihiro, Hisano, Setsuji
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.10.2006; Blackwell
• Subjects: Alternative Splicing; Animals; Biochemistry; Biological and medical sciences; Brain - physiology; Central nervous system; Central neurotransmission. Neuromudulation. Pathways and receptors; ciliary neurotrophic factor; DNA - genetics; DNA - isolation & purification; DNA Primers; Fundamental and applied biological sciences. Psychology; Gene expression; Gene Expression Regulation, Developmental; Genetic Variation; Hormones and neuropeptides. Regulation; Hypothalamus. Hypophysis. Epiphysis. Urophysis; Organ Specificity; pineal gland; Pineal Gland - physiology; Prenatal development; Proteins; Rats; Retina; Retina - physiology; Reverse Transcriptase Polymerase Chain Reaction; rhodopsin; Ribonucleic acid; RNA; RNA, Messenger - genetics; RNA, Messenger - metabolism; Rodents; splice variant; Vertebrates: endocrinology; Vertebrates: nervous system and sense organs; Vesicular Glutamate Transport Protein 1 - genetics; vesicular glutamate transporter 1; Alternative splicing; Rat; Photoreceptor; Retina; pineal gland; ciliary neurotrophic factor; Eye; rhodopsin; Visual system; Development; VGLUT glutamate transporter; Release; Rod; Rodentia; VGLUT1 glutamate transporter; Glutamate; Hand; Vertebrata; Synapse; Mammalia; Excitatory aminoacid; Neurotransmitter; vesicular glutamate transporter 1; Subtype; splice variant
• ISSN: 0022-3042; 1471-4159
• DOI: 10.1111/j.1471-4159.2006.04049.x

Three distinct subtypes of vesicular glutamate transporters (VGLUTs) have been identified to date that are expressed basically in a cell type‐specific manner. We have found a splice variant of VGLUT1 mRNA that is expressed almost exclusively in photosensitive tissues, i.e. the retina and the pineal gland. The variant mRNA, termed VGLUT1v, contains an additional 75 base pair sequence derived from part of a second intron (designated as exon IIa) between exons 2 and 3. The variant accounted for approximately 70% and 25%of VGLUT1 mRNA in the adult retina and pineal gland, respectively. The expression of VGLUT1v was developmentally regulated in both tissues. Organ culture showed that expression of the variant in the retina increased in association with the development of rod cells, suggesting that VGLUT1v is expressed in rod cells. In situ hybridization with variant‐specific probes showed expression of VGLUT1v in the inner segment layer of photoreceptor cells. On the other hand, variant expression did not parallel the development of rhodopsin‐positive cells in the pineal gland. As rod cells and pinealocytes are known to release glutamate continuously at ribbon synapses, it is possible that the variant has some functional advantage over the wild‐type transporter in such a specialized manner of glutamate release.