Mammalian pyruvate kinase (PK), a key glycolytic enzyme, has two genes named PKL and PKM, which produce the L- R-type isoenzymes by means of alternative promoters, M1-and M2-types mutually exclusive splicing respectively. The expression these is tissue-specific under developmental, dietary hormonal control. L-type isoenzyme (L-PK) gene contains multiple regulatory elements necessary for regulation in 5' flanking region, up to position -170. Both L-II L-III are required stimulation L-PK...

The effects of nutrients and hormones on transcriptional post-transcriptional regulation fatty acid synthase in rat liver were investigated following cDNA cloning. When fasted rats fed a carbohydrate/protein diet, the rate was greatly increased even 1 h. rate, mRNA concentration enzyme induction reached maximum levels 4 h, 8-16 h 48 respectively. Although dietary carbohydrate each level more than protein did, both required to reach high level. Corn oil feeding markedly decreased rate. In...

The effects of nutrients and hormones on transcriptional post‐transcriptional regulation acetyl‐CoA carboxylase in rat liver were investigated following a cDNA cloning. After refeeding carbohydrate/protein diet to fasted rats, the rate was increased 2.5‐fold only 1 h. mRNA concentration reached maximal level 9–12‐fold increase 8–16 h, enzyme induction 10‐fold 48 By carbohydrate without protein, rate, similarly levels diet. It appears that protein feeding is not necessary induce carboxylase....

The type 3 form of maturity-onset diabetes the young (M0DY3) results from mutations in gene encoding transcription factor, hepatocyte nuclear factor-1α (HNF-1α). mechanism by which only one allele HNF-1α impair pancreatic β-cell function is unclear. functional a dimer—either homodimer or heterodimer with structurally related protein HNF-1β—that binds to and activates genes whose expression it regulates. composed three domains: an amino-terminal dimerization domain (amino acids 1–32),...

Genomic clones containing the human pyruvate kinase M (PKM) gene, which encodes 1 ‐type and 2 isozymes, were isolated their exon sequences determined. The gene is approximately 32 kb consists of 12 exons 11 introns. Exons 9 10 contain specific to types, respectively, indicating that isozymes are produced from same by alternative splicing as in case rat gene. exon‐intron structure PKM identical introns both genes interrupt at points. Introns 6 7 begin with GC dinucleotide instead consensus...

The effects have been studied of streptozotocin‐induced diabetes and subsequent insulin administration or feeding a high fructose diet on the amount enzyme protein mRNA activity L‐type pyruvate kinase in rat liver. Diabetes markedly decreased liver treatment resulted restoration to normal. A also increased diabetic rats but lesser extent. Immunochemical analysis showed that these alterations were due changes immunoreactive protein. mechanism was further by assaying level functional coding...

Pyruvate kinase M₁, a non-allosteric isozyme, was converted into an allosteric enzyme by replacement of amino acid in the intersubunit contact. The substitution Ala-398 with Arg resulted pronounced enzyme. Hill coefficient and substrate concentration giving one-half <i>V</i> _max for mutant respect to phosphoenolpyruvate were 2.7 0.41 mm, respectively, whereas those values wild type 1.0 0.049 mm. This mutation, however, gave rise only minor effects on apparent <i>K</i>...

The three distal transcriptional regulatory elements of the rat pyruvate kinase M gene, referred to as boxes A, B, and C, are located around −270 base pairs upstream from initiation site. Electrophoretic mobility shift assays with specific competitors antibodies show that both box A B bind Sp1 Sp3 C binds nuclear factor-Y (NF-Y). Luciferase reporter revealed although alone have no independent effect on luciferase activities, stimulates transcription. However, inclusion all lead maximal...

We isolated two cDNA clones of rat Hex, a homeobox protein, studied its expression in liver and various cells, characterized the protein. The levels Hex mRNA were only slightly increased rats refed with high-carbohydrate diet or after partial hepatectomy. Whereas was detected hepatocytes from adult also highly differentiated hepatoma no poorly cells. embryo aged 15 days. Expression F9 cells during differentiation into visceral endoderm by treatment retinoic acid. This stimulation occurred...

cDNA clones, containing the entire coding region of rat L-type pyruvate kinase, were isolated and their nucleotide sequences determined by dideoxy-chain-termination method. The predicted region, which spans 543 amino acids, established complete acid sequence isozyme kinase for first time. deduced L type has one phosphorylation site in its terminus shows about 68% 48% homologies with M1-type chicken yeast respectively. Domain A exhibits higher homology than domains B C. residues active enzyme...

Pyruvate kinase M2 isozyme mutants with amino acid substitutions in the subunit interface were prepared and characterized. The made allosteric by corresponding residues of nonallosteric M1 to identify residue involved effects. replacement Cys-423 Leu led substantial loss both homotropic heterotropic effects while at Phe-389, Arg-398, Ala-401, Pro-402, Thr-408, Ile-427 did not. altered kinetic properties Cys-423-substituted mutant resulted from shift transition toward active R-state since...

Fasted rats were refed a carbohydrate/protein diet, carbohydrate diet (without protein) or protein carbohydrate) to investigate, using cDNA cloned in our laboratory, the regulatory mechanisms involved hepatic malic enzyme induction. In although activity and mRNA concentration of increased about 7-fold above levels fasted rat, rate transcription was only 2-fold. group group, whereas 60% those levels. Protein appears contribute an increase translation mRNA. transcriptional not low, but half...

The onset of Hex expression and its role in early murine development was analyzed using situ hybridization. mRNA first detected the chorion ectoplacental cavity weakly at visceral endoderm future yolk sac embryonic age (E) 7.5. Expression tissues exclusively hepatic anlage thyroid primordium E 9.5. At 12.5 15.5, persisted fetal liver thyroid, also lung. These results suggest that has differentiation and/or organogenesis several tissues.

In rats fed ad libitum, a marked circadian rhythm with peak at night was observed in the hepatic level of ornithine decarboxylase (ODC) [EC 4.1.1.17], enzyme for first step polyamine synthesis. A similar found content putrescine, but not spermidine or spermine. The mitotic activity liver also exhibited clear daytime. rhythms both ODC and mitosis were generated by cyclic ingestion proteinous food, since peaks shifted when meal-fed activities disappeared on starvation protein deprivation....

The intraperitoneal injection of either hydrocortisone or N6,O2′-dibutyryladenosine 3′,5′-phosphate (Bt2cAMP) results in a specific increase functional tyrosine aminotransferase mRNA (mRNATAT) activity rat liver that is proportional to the degree enzyme induction. Both require continuous RNA synthesis. There are several differences response these inducers: (a) magnitude greater following than after Bt2cAMP; (b) peak seen within 1 h Bt2cAMP as compared 5 required for maximal injection; (c)...

The L-II element (-149 to -126 bp) in the enhancer unit of rat pyruvate kinase L (PKL) gene is required for cell-type-specific transcription and induction by carbohydrates. This was found bind multiple nuclear proteins with different heat stabilities. A heat-labile factor shown be hepatocyte (HNF) 4 electrophoretic mobility-shift assay (EMSA) using various competitor DNAs anti-HNF4 serum. heat-stable purified from liver extract resolved as two protein bands migrating at about 33 kDa on...

The M1-type and M2-type isozymes of pyruvate kinase are produced from a single gene by mutually exclusive use exons 9 10. Selection exon 10 generates the M2 type, which occurs in most tissues, whereas M1 type is expressed only skeletal muscle, heart brain. We investigated mechanism 10, but not selected M2-expressing cells transfecting minigenes containing and/or analyzing transcripts using reverse-transcriptase polymerase chain reaction. Deletion conserved region intron 8 did affect...