Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.48 (transcriptase)
 9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Synaptic transmission from glutamatergic neurons requires vesicular glutamate transporters (VGLUTs) to concentrate cytosolic glutamate in synaptic vesicles. In retina, glutamatergic photoreceptors and bipolar cells exclusively express the VGLUT1 isoform, whereas ganglion cells express VGLUT2. Surprisingly, the recently identified VGLUT3 isoform was found in presumed amacrine cells, generally considered to be inhibitory interneurons. To investigate the synaptic machinery and conceivable secondary neurotransmitter composition of VGLUT3 cells, and to determine a potential functional role, we further investigated these putative glutamatergic amacrine cells in adult and developing rodent retina. Reverse transcriptase-PCR substantiated VGLUT3 expression in mouse retina. VGLUT3 cells did not immunostain for ganglion or bipolar cell markers, providing evidence that they are amacrine cells. VGLUT3 colocalized with synaptic vesicle markers, and electron microscopy showed that VGLUT3 immunostained synaptic vesicles. VGLUT3 cells were not immunoreactive for amacrine cell markers gamma-aminobutyric acid, choline acetyltransferase, calretinin, or tyrosine hydroxylase, although they immunostain for glycine. VGLUT3 processes made synaptic contact with ganglion cell dendrites, suggesting input onto these cells. VGLUT3 immunostaining was closely associated with the metabotropic glutamate receptor 4, which is consistent with glutamatergic synaptic exocytosis by these cells. In the maturing mouse retina, Western blots showed VGLUT3 expression at postnatal day 7/8 (P7/8). VGLUT3 immunostaining in retinal sections was first observed at P8, achieving an adult pattern at P12. Thus, VGLUT3 function commences around the same time as VGLUT1-mediated glutamatergic transmission from bipolar cells. Furthermore, a subset of VGLUT3 cells expressed the circadian clock gene period 1, implicating VGLUT3 cells as part of the light-entrainable retina-based circadian system.
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PMID:Vesicular glutamate transporter 3 expression identifies glutamatergic amacrine cells in the rodent retina. 1532 88

Vesicular glutamate transporters (VGLUT1, -2, and -3) mediate the accumulation of transmitter glutamate into synaptic vesicles in glutamatergic neurons. VGLUT1 and VGLUT2 are more reliable glutamatergic neuron markers, since VGLUT3 also exists in other neuron types. To study whether the dopaminergic neuron uses glutamate as a cotransmitter, we analyzed VGLUTs expression in dopamine neurons of adult male rats by in situ hybridization and immunohistochemistry. In the ventral midbrain, in situ hybridization analysis revealed no VGLUT1 mRNA expression, a widespread but discrete pattern of VGLUT2 mRNA expression, and a highly limited expression of VGLUT3 mRNA. Reverse-transcriptase polymerase chain reaction analysis detected full-length VGLUT2 gene transcripts in the ventral midbrain. Using in situ hybridization combined with tyrosine hydroxylase (TH) immunostaining, only VGLUT2 signals were detectable in some TH-labeled neurons of A10 dopamine neuron groups, with the highest incidence (20%) in the rostral linear nucleus of the ventral tegmental area. In the forebrain, VGLUT2 signals were demonstrated in half of the A11 TH-labeled neurons in the hypothalamus. Double-label immunostaining for VGLUT2 and vesicular monoamine transporter 2 or TH showed that double-labeled varicosities are rarely observed in any target regions examined of A10 and A11 dopamine neuron groups. These results indicate that VGLUT2 is expressed in subsets of A10 and A11 dopamine neurons, which might release dopamine and glutamate separately from different varicosities in the majority of their single axons.
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PMID:Particular subpopulations of midbrain and hypothalamic dopamine neurons express vesicular glutamate transporter 2 in the rat brain. 1691 21

In the light of the various neurobiological effects of glutamate in brain development, although some embryonic cells are a probable source of glutamate involved in the development of precursor cells and/or immature neurons, little is known about when and where glutamate plays its crucial roles during corticogenesis. To investigate these roles, we focused on the developmental expression of vesicular glutamate transporter (VGLUT)1 and VGLUT2, which are regarded as the best markers for verifying glutamatergic neuron identity, especially the spatiotemporal distributions of their transcripts and proteins in the developing mouse cortex and hippocampus. In situ hybridization studies revealed that VGLUT1 mRNA is expressed in preplate and marginal zone cells at embryonic day (E)10 and in subplate cells by E13, whereas VGLUT2 mRNA is expressed in preplate and marginal zone cells at E10 and in cells of the subventricular zone by E13. Reverse transcriptase-polymerase chain reaction analysis detected full-length VGLUT1 and VGLUT2 gene transcripts in the embryonic brain. By dual labeling combined with immunostaining for microtubule-associated protein 2 (MAP2) or reelin, we showed that MAP2-positive preplate and marginal zone neurons and subplate neurons express VGLUT1, while reelin-positive preplate and marginal zone cells and MAP2-negative subventricular zone cells express VGLUT2. The present study is the first to provide morphologically reliable evidence showing that Cajal-Retzius cells and subplate neurons are glutamatergic, and that the two cells differentially express VGLUT1 and VGLUT2, respectively, as the specific transport system of glutamate in some events orchestrated by these cells during the cortical development of mice.
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PMID:Cajal-Retzius cells and subplate neurons differentially express vesicular glutamate transporters 1 and 2 during development of mouse cortex. 1765 22