Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.49 (reverse transcriptase)
 31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The gene coding for starch phosphorylase (EC 2.4.1.1) was isolated from a potato genomic library constructed in lambda EMBL3. It is an unusually long plant gene (16.4 kb) which encodes a preprotein of 966 amino acids. The phosphorylase coding sequence is interrupted by 14 introns whose positions do not match those of the introns in the human glycogen phosphorylase gene. A 78 amino acid central peptide unique to plant plastidial phosphorylases is hypothesized to have arisen through the mis-splicing of an intron-exon junction site in an ancestral gene. The fifth intron of the phosphorylase is very large (approximately 7 kb) and contains a copia-like transposable element inserted in the opposite orientation to that of the phosphorylase gene. This element has been named Tst1; it is bordered on the 5' and 3' sides by long terminal repeats of 285 and 283 bp respectively, which define an internal domain of 4492 bp. Tst1 contains 4 open reading frames (ORFs) that encode protein domains for a reverse transcriptase, an integrase, an RNA-binding site and a protease. Transcription of the phosphorylase gene appears to proceed unimpaired through the copia element.
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PMID:Occurrence of a copia-like transposable element in one of the introns of the potato starch phosphorylase gene. 170 27

Of the three isozymes of glycogen phosphorylase (GP) known, the brain (B) and muscle (M) isoforms have been reported to occur in brain. We investigated the regional and cellular occurrence of the three isozymes in various parts of the rat nervous system, fetal brain and astroglia-rich primary cultures by means of electrophoresis of native proteins with subsequent activity stain and by reverse transcriptase polymerase chain reaction. In the cortex, cerebellum, olfactory bulb, brainstem, spinal cord and dorsal root ganglia, both mRNA and enzyme protein were found for the B and M isozymes. In addition, the liver (L) isoform mRNA was detected in fetal brain and cultured astrocytes. Our studies indicate that there is no regional difference in distribution pattern between brain regions, spinal cord and dorsal root ganglia. In immature brain and cultured glial cells, the additional presence of the L isozyme is possible. These results support the idea that astrocytes express two or even three GP isozymes simultaneously.
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PMID:Isozyme pattern of glycogen phosphorylase in the rat nervous system and rat astroglia-rich primary cultures: electrophoretic and polymerase chain reaction studies. 1107 67

Kidney contains glycogen. Glycogen is degraded by glycogen phosphorylase (GP). This enzyme comes in three isoforms, one of which, the brain isozyme (GP BB), is known to occur in kidney. Its pattern of distribution in rat kidney was studied in comparison to that of the muscle isoform (GP MM) with the aim to see if for GP BB and GP MM there were functional similarities in brain and kidney. In immunoblotting and quantitative reverse transcriptase polymerase chain reaction (RT-PCR) experiments, both isozymes and their respective mRNAs were found in kidney homogenates. GP BB was immunocytochemically detected in collecting ducts which were identified by the marker protein aquaporin-2. GP MM was localized exclusively in interstitial cells of cortex and outer medulla. These cells were identified as fibroblasts by their expression of 5'-ectonucleotidase (cortex) or by their morphology (outer medulla). The physiological role of both isozymes is discussed in respect to local demands of energy and of proteoglycan building blocks.
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PMID:Renal expression of the brain and muscle isoforms of glycogen phosphorylase in different cell types. 1833 48

Heart glycogen represents a store of glucosyl residues which are mobilized by the catalysis of glycogen phosphorylase (GP) and are mainly destined to serve as substrates for the generation of ATP. The brain isoform of GP (GP BB) was studied in rat heart in comparison with the muscle isoform (GP MM) to find functional analogies to the brain. Western blotting and quantitative reverse transcriptase polymerase chain reaction (RT-PCR) experiments revealed that at the protein level, but not at the mRNA level, the content of GP BB is similar in heart and brain. In contrast, GP MM is more abundant in the heart than in the brain. Immunocytochemically GP BB was colocalized with GP MM in cardiomyocytes. GP MM was also detected in interstitial cells identified as fibroblasts. The physiological role of co-expression of GP BB and GP MM in cardiomyocytes and in brain astrocytes is discussed in a comparative way.
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PMID:Expression of the brain and muscle isoforms of glycogen phosphorylase in rat heart. 1875 94

Using rapid amplification of cDNA ends, a full-length cDNA sequence of a GDP-L-galactose phosphorylase-like gene was isolated from leaves infected by Erysiphe necator in the Chinese wild (Vitis pseudoreticulata) clone, 'Baihe-35-1', an E. necator-resistant genotype. The full-length cDNA, designated as VpVTC, comprised 1943 bp and putatively encodes a 453-amino acid polypeptide containing an HIT motif. The deduced amino acid sequence showed high similarity with that of VTC genes from other plants. The expression of VpVTC, determined by reverse transcriptase-polymerase chain reaction, was induced by E. necator and defense signaling molecules, including salicylic acid, methyl jasmonate, and ethephon, in 'Baihe-35-1', the V. quinquangularis genotype 'Shang-24', and the E. necator-susceptible V. pseudoreticulata genotype, 'Hunan-1'. Transcript levels of VpVTC correlated well with the degree of disease resistance in the 3 genotypes. Maximum induction of VpVTC by E. necator (>7-fold at 96 h post-inoculation) occurred in 'Baihe-35-1', which also showed the fastest response to signaling molecules. Upregulating the expression of VpVTC in 'Baihe-35-1' resulted in a gradual increase in the ascorbic acid concentration of leaves inoculated with E. necator. Furthermore, VpVTC was expressed in leaves, stems, inflorescence, tendrils, and fruit at all developmental stages, with the highest level occurring in fruit 35 days after flowering.
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PMID:Expression of a GDP-L-galactose phosphorylase-like gene in a Chinese wild Vitis species induces responses to Erysiphe necator and defense signaling molecules. 2408 44