Disease relevance of Aldob

• At the terminal stage of hepatocarcinogenesis, i.e. in malignant hepatoma cells, expression and inducibility of aldolase B and L-type pyruvate kinase mRNAs were similar to those in normal adult rats while mRNAs specific for undifferentiated or foetal stages were also synthesized [1].

High impact information on Aldob

• Eight dag populations and eight clones are characterized as being different from Faof1 cells by the production of serum albumin, aldolase B and in some cases activity of alcohol dehydrogenase and alanine aminotransferase [2].
• Dietary and hormonal regulation of aldolase B gene expression [3].
• In the liver, but not in the kidney, diabetes and glucagon administration abolished the induction of aldolase B mRNAs in animals refed the maltose-rich diets [3].
• The hormonal control of aldolase B mRNA levels in the small intestine is intermediate [3].
• A region encompassing the rat aldolase B gene (aldB) promoter acts as a chromosomal origin of DNA replication (origin) in rat aldolase B-nonexpressing hepatoma cells [4].

Biological context of Aldob

• The amino acid sequence of rat liver aldolase B is composed of 364 amino acids and has 70% homology with rabbit muscle aldolase A [5].
• The nucleotide sequence of messenger RNA encoding rat liver aldolase B has been determined by sequence analysis using recombinant cDNAs cloned in bacterial plasmids [5].
• Nucleotide sequence of rat liver aldolase B messenger RNA [5].
• By overlapping restriction maps of several individual cDNA inserts, it was found that they spanned 1200 base pairs, which represented about 70% of the aldolase B mRNA sequence [6].
• These data indicate the presence of a modulated enzyme-enzyme interaction between FBPase and isoenzyme B. They affirm that in kidney, aldolase B specifically participates, along the gluconeogenic pathway and aldolase A in glycolysis [7].

Anatomical context of Aldob

• Rat aldolase B mRNA was partially purified from liver polysomes by an immunochemical technique followed by oligo(dT)-cellulose column chromatography [6].
• We propose that aldolase B is ubiquitinated within the cytosol and then transported into autophagosomes and autolysosomes for degradation during nutrient stress [8].
• Similar experiments using RNAs from fetuses at later stages, however, showed that aldolase B mRNA increased during development, whereas aldolase A mRNA decreased [9].
• Aldolase A (muscle type) bound more tightly to the skeletal muscle cytoskeleton among the three isozymes, while aldolase B (liver type) preferred the liver cytoskeleton to those of other tissues [10].
• These findings suggest that the differentiated hepatocyte maintains a differentiated state during the liver regeneration as seen in aldolase B, whereas "oncofetal" isozymes such as aldolase A resurge after partial hepatectomy under the control of post-transcriptional mechanism [11].

Associations of Aldob with chemical compounds

• Although the complete amino acid sequence of rat aldolase B has not yet been reported, it was found that several amino acids neighboring the COOH-terminal tyrosine obtained by carboxypeptidase digestion completely coincided with those determined from the cDNA sequence; i.e. -Ser-Leu-Phe-Thr-Ala-Ser-Tyr-Thr-Tyr [6].
• In contrast, parenchymal cells isolated from the livers of these animals had only aldolase B and pyruvate kinase L, the same isozymes present in parenchymal cells of normal adult rats [12].
• This degradation was suppressed by chloroquine and 3-methyladenine, suggesting that aldolase B was being degraded within autolysosomes [8].
• Aminopeptidase and alkaline phosphatase were found from 3 days before birth in proximal tubule cells, aldolase-B and aldolase-A in all the nephron and collecting duct [13].
• Using a cDNA probe complementary to rat aldolase B mRNA, we determined the amount of cytoplasmic RNAs in the liver, kidney, and small intestine of normal, adrenalectomized, thyroidectomized, diabetic, and glucagon- or cAMP-treated animals refed either a fructose-rich or a maltose-rich diet [3].

Regulatory relationships of Aldob

• However, the mechanism of how interleukin-6 regulates aldolase B and albumin syntheses in hepatocytes is not completely understood [14].
• Glucagon rapidly suppressed aldolase B gene expression at the transcriptional level [15].

Other interactions of Aldob

• The same pattern of distribution was found for PK, but not for aldolase B, PEPCK, and FBPase [7].
• In contrast, aldolase B, aldolase C and albumin mRNAs did not change at all [11].
• At that time, glycogen content was significantly reduced, but no obvious changes in albumin, beta-actin and aldolase B mRNAs and in glutathione levels were observed [16].
• Quantitative evaluation of HNF4alpha-regulated pancreatic beta-cell gene expression revealed altered mRNA levels of insulin, glucose transporter-2, L-pyruvate kinase, aldolase B, 2-oxoglutarate dehydrogenase E1 subunit, and mitochondrial uncoupling protein-2 [17].
• 5-Azacytidine treatments also increased, but to a lesser extent, mRNAs level for actin, albumin, mitochondrial aspartate aminotransferase, aldolase B mRNAs (12- to 16-fold) as well as for tubulin, gluthathione transferase, and tyrosine aminotransferase mRNAs (2- to 5-fold) [18].

Analytical, diagnostic and therapeutic context of Aldob

• Quantitative evaluation of HNF-4alpha target gene expression revealed diminished mRNA levels for HNF-1alpha, GLUT2, L-type pyruvate kinase, aldolase B, apolipoprotein (apo)-B, and apoCIII [19].
• Plasmids DNAs of some pyruvate kinase and aldolase B clones (whose inserts ranged from 700 to 1050 bases in length) were labeled by nick translation and used as probes for Northern blot hybridization [20].
• Molecular cloning of cDNA for rat L-type pyruvate kinase and aldolase B [20].
• The reduced aldolase activity following PenCB-treatment was due to the marked suppression of the expression of aldolase B shown by immunoblot analysis after SDS-polyacrylamide gel electrophoresis and two-dimensional gel electrophoresis [21].
• Free ribosomes and membrane-bound ribosomes were prepared from rat livers, and the contributions of these two types of ribosomes to the synthesis of aldolase B were studied by the immunoprecipitation of [3H]puromycin-labeled nascent peptides with a rabbit antibody to this enzyme [22].

References