Immunohistochemical localization of glutamate dehydrogenase in rat liver: plasticity of distribution during development and with hormone treatment.

Lamers, W. H.; Janzen, J. W. Gaasbeek; Moorman, Antoon F.M.; Charles, R.; Knecht, Erwin; Martinez-Ramon, Amelia; Hernández-Yago, José; Grisolı́a, Santiago

doi:10.1177/36.1.3335769

Cited by 35 publications

(20 citation statements)

References 4 publications

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“…This cRNA was incubated with rat liver polyadenylated RNA (lanes 4 and 5) or wheat-germ tRNA (lanes 6 and 7). Non-hybridizing sequences were digested with RNase A (lane 4 …”

Section: Constructmentioning

confidence: 99%

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Isolation and characterization of the rat gene encoding glutamate dehydrogenase

Das

Arnberg

Malingré

et al. 1993

European Journal of Biochemistry

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The concentration of glutamate dehydrogenase (GDH) varies strongly between different organs and between different regions within organs. To permit further studies on the regulation of GDH expression, we isolated and characterized the rat gene encoding the GDH protein. This gene contains 13 exons and spans approximately 34 kbp. The GDH gene is present as a single, autosomally located copy in the Wistar rat genome, but shows an extensive restriction-fragment-length polymorphism for several enzymes. Promoter activity of the 5'-flanking sequence is shown by transient transfection experiments. The 5'-flanking sequence contains a TTAAAA sequence at position -29, instead of a consensus TATA box and, like many other TATA-less promoters, is characterized by a very high G + C content. In addition, consensus sequences for the binding sites of the transcription factors Spl and Zif268 are present in the G + C-rich upstream region.Glutamate dehydrogenase (GDH), a mitochondria1 matrix enzyme, catalyzes the reversible oxidative deamination of L-glutamate to 2-oxoglutarate and ammonia, using NAD' or NADP' as cofactor [l]. GDH therefore plays an important role in ammonia and amino acid metabolism. Although GDH is an ubiquitous enzyme, its concentration in different organs varies markedly, the highest concentrations being found in liver, brain, kidney and pancreas [2, 31.In liver GDH is highly expressed only in the hepatocytes. In the adult rat [4-91 and human [lo] liver the GDH concentration depends on the position of the hepatocyte along the central-portal distance, the highest activity and protein concentration being found in hepatocytes around the central veins. In rat liver two mRNAs are present which differ in the length of their 3'-untranslated region [ l l , 121. As shown by in situ hybridization, these mRNAs are also heterogeneously distributed within the adult rat liver, both showing a gradient in cellular concentration decreasing along the central-portal distance [13]. The heterogeneous mRNA distribution in the liver lobule demonstrates the presence of regional differences in the rate of pretranslational processes involved in GDH

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“…This cRNA was incubated with rat liver polyadenylated RNA (lanes 4 and 5) or wheat-germ tRNA (lanes 6 and 7). Non-hybridizing sequences were digested with RNase A (lane 4 …”

Section: Constructmentioning

confidence: 99%

“…Intron-exon organization of the GDH gene. The size and position of the exons [1][2][3][4] were determined by Southern blot and sequence analysis. The size and position of the other exons were determined by electron microscopy of genomic DNA .…”

Section: Intron/exon Analysismentioning

confidence: 99%

Isolation and characterization of the rat gene encoding glutamate dehydrogenase

Das

Arnberg

Malingré

et al. 1993

European Journal of Biochemistry

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“…Evidence has been presented that genäse is present in all hepatocytes; however, similar to alanine and proline, most gluco-its distribution shows a U-shaped gradient neogenic amino acids (apart from aspartate along the lobule with highest activities at the and glutamate) are predominantly taken up periportal and perivenous end of the lobule by periportal hepatocytes, i.e. into a com- [6], Apart from the uptake and catabolism of partment exhibiting a high capacity for glu-most amino acids and urea synthesis, also coneogenesis and ureogenesis [23,40,41] chyma to which the expression of a gene is confined, irrespective of the concentrations of modulatory factors. The best paradigm of the compartment type of zonation is the reciprocal distribution of the ammonia-me tabolizing enzymes carbamoylphosphate syn thase and glutamine synthase [46], As a consequence of such straight forward dichotomy in the patterns of hepatic gene expression, the central problem concerning the topography of gene expression in the liver becomes directly focussed on the origin and maintenance of gradients and compart ments of gene expression within the liver lobule, and on the problem of whether differ ent lineages of hepatocytes exist or whether the hepatic architecture is the dominant fac tor.…”

Section: Zonation Of Enzymes and Metabolic Capacitiesmentioning

confidence: 99%

“…The positional regula tion of glutamate dehydrogenase seems more complex. Glutamate dehydrogenase mRNA is expressed in all hepatocytes in a gradient decreasing in concentration in a central-por tal direction [11], Enzyme activities show a similar distribution [41, 50,51], In contrast, glutamate dehydrogenase protein has a Ushaped distribution across the porto-central distance [6], Obviously, lack of specificity of the antibodies and/or the immunohisto chemical procedures used, might account for these unexplained discrepancies. However, this possibility seems unlikely as both mono clonal and polyclonal antibodies gave simi lar results.…”

Section: Patterns Of Gene Expression In the Adult Livermentioning

confidence: 99%

Hepatocyte Heterogeneity in the Metabolism of Amino Acids and Ammonia

Häussinger¹,

Lamers²,

Moorman³

1992

Enzyme

206

134

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With respect to hepatocyte heterogeneity in ammonia and amino acid metabolism, two different patterns of sublobular gene expression are distinguished: ‘gradient-type’ and ‘strict- or compartment-type’ zonation. An example for strict-type zonation is the reciprocal distribution of carbamoylphosphate synthase and glutamine synthase in the liver lobule. The mechanisms underlying the different sublobular gene expressions are not yet settled but may involve the development of hepatic architecture, innervation, blood-borne hormonal and metabolic factors. The periportal zone is characterized by a high capacity for uptake and catabolism of amino acids (except glutamate and aspartate) as well as for urea synthesis and gluconeogenesis. On the other hand, glutamine synthesis, ornithine transamination and the uptake of vascular glutamate, aspartate, malate and a-ketoglutarate are restricted to a small perivenous hepatocyte population. Accordingly, in the intact liver lobule the major pathways for ammonia detoxication, urea and glutamine synthesis, are anatomically switched behind each other and represent in functional terms the sequence of the periportal low affinity system (urea synthesis) and a previous high affinity system (glutamine synthesis) for ammonia detoxication. Perivenous glutamine synthase-containing hepatocytes (‘scavenger cells’) act as a high affinity scavenger for the ammonia, which escapes the more upstream urea-synthesizing compartment. Periportal glutaminase acts as a pH- and hormone- modulated ammonia-amplifying system in the mitochondria of periportal hepatocytes. The activity of this amplifying system is one crucial determinant for flux through the urea cycle in view of the high K(m) (ammonia) of carbamoylphosphate synthase, the ratecontrolling enzyme of the urea cycle. The structural and functional organization of glutamine and ammonia-metabolizing pathways in the liver lobule provides one basis for the understanding of a hepatic role in systemic acid base homeostasis. Urea synthesis is a major pathway for irreversible removal of metabolically generated bicarbonate. The lobular organization enables the adjustment of the urea cycle flux and accordingly the rate of irreversible hepatic bicarbonate elimination to the needs of the systemic acid base situation, without the threat of hyperammonemia.

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“…In adult rat liver, GDH is highly expressed only in the hepatocytes and the level of expression depends on the position of the hepatocyte along the porto-central axis, the highest activity, protein and mRNA concentrations being found in hepatocytes around the central veins . Furthermore, changes in the distribution pattern of GDH protein and mRNA, due to an enhanced expression in the hepatocytes around the terminal portal veins, were shown to occur during development and with changes in the hormonal status of the animal [17,181. To be able to study the apparently complex regulation of GDH expression, we recently isolated the GDH gene of the rat [201.…”

mentioning

confidence: 99%

Identification and analysis of a matrix‐attachment region 5′ of the rat glutamate‐dehydrogenase‐encoding gene

Das¹,

Ludérus²,

Lamers³

1993

European Journal of Biochemistry

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Eukaryotic chromatin is thought to be organized into independently regulated loop domains by interaction of matrix‐attachment regions (MAR) of the DNA to the nuclear matrix. To define the borders of the chromatin loop containing the glutamate dehydrogenase (GDH) gene, we screened the GDH gene and flanking regions for the presence of MAR sequences. We here report identification, mapping and sequencing of an (A+T)‐rich MAR located 2010–1397 bp upstream of the transcription initiation site of GDH, that mediates strong binding to the nuclear matrix. Smaller regions can also confer binding capacity, although at a lower affinity. This (A+T)‐rich MAR contained 11 bp and 12 bp (A+T)‐rich direct repeats, but not any of the sequences previously described to be associated with MAR activity. We here show that the presence of (A+T)‐rich domains of DNA is not sufficient to confer binding capacity, since (A+T)‐rich sequences located downstream of the identified MAR did not bind to the nuclear matrix. Moreover, a consensus topoisomerase‐II‐binding site located downstream of the MAR was found to be insufficient to mediate substantial binding. The number of binding sites in the nuclear matrix for MAR‐containing fragments was shown to be approximately 15 000/nucleus. Since organization of the entire rat genome in loops with an average loop size of 100 kbp would require 60 000 binding sites, this suggests that only part of the genome is organized in loops. Alternatively, we might have underestimated the number of binding sites. The GDH MAR, and MAR‐containing fragments derived from other species, were found to bind to the same binding sites in the nuclear matrix, although the affinity varied.

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Immunohistochemical localization of glutamate dehydrogenase in rat liver: plasticity of distribution during development and with hormone treatment.

Cited by 35 publications

References 4 publications

Isolation and characterization of the rat gene encoding glutamate dehydrogenase

Isolation and characterization of the rat gene encoding glutamate dehydrogenase

Hepatocyte Heterogeneity in the Metabolism of Amino Acids and Ammonia

Identification and analysis of a matrix‐attachment region 5′ of the rat glutamate‐dehydrogenase‐encoding gene

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