An acute phase response factor/NF-kappa B site downstream of the junB gene that mediates responsiveness to interleukin-6 in a murine plasmacytoma.

The immediate early gene, junB, is induced by interleukin-6 (IL-6) in plasmacytomas. In order to identify enhancers that mediate this effect, we cloned upstream and downstream sequences flanking the gene into a luciferase reporter gene vector containing the junB promoter and evaluated the IL-6 inducibility of these sequences by transient expression in an IL-6-dependent plasmacytoma cell line. Although a 6.

Production of delta-aminolevulinic acid: characterization of murine liver 4,5-dioxovaleric acid: L-alanine aminotransferase.

1. We report on the kinetic properties of murine liver 4,5-dioxovaleric acid:L-alanine aminotransferase (DOVA transaminase). 2.

Production of delta-aminolevulinate: subcellular localization and purification of murine hepatic L-alanine: 4,5-dioxovaleric acid aminotransferase.

1. L-Alanine: 4,5-dioxovaleric acid aminotransferase (DOVA transaminase) activity was measured in murine liver, kidney and spleen homogenates. 2.

Mitochondrial biogenesis: do liver mitochondria contain glycoproteins and glycosyltransferases?

1. Subcellular fractions isolated from livers of 19-day-old chicken embryos were analyzed in order to assess whether liver mitochondria contained glycosylated proteins or had mannosyl- or sialyl-transferases that could transfer sugars to mitochondrial macromolecules. 2.

Induction of cytochrome P-450 RNA by porphyrogenic agents: on the nature of the coordinate induction with delta-aminolevulinate synthase in tissues of the chicken embryo.

1. We determined by cDNA-RNA solution hybridization analyses that in ovo administration of allylisopropylacetamide in combination with diethyl 1,4-dihydro-2,4,6-trimethyl-3,5-pyridinedicarboxylate increased the concentrations of cytochrome P-450 RNA in liver, kidney, and intestine of 18-day-old chicken embryos. 2.

Regulation of production of delta-aminolaevulinate synthase in tissues of chick embryos. Effects of porphyrogenic agents and of haem precursors.

Studies conducted by several groups have established that porphyrogenic agents which caused elevations in chick-embryo liver delta-aminolaevulinate (ALA) synthase activity also increased the concentrations of the enzyme's RNA, and that haemin inhibited these elevations. We have determined in this study, using immune-blot analyses, that administration in ovo of allylisopropylacetamide (AIA) in combination with diethyl 1,4-dihydro-2,4,6-trimethyl,3,5-pyridinedicarboxylate (DDC) increased the mass of ALA synthase in intestine and kidney of chick embryos. Furthermore, the molecular mass of the subunit of the enzyme in those tissues appeared identical with that of liver ALA synthase.

Regulation of the stability of chicken embryo liver delta-aminolevulinate synthase mRNA by hemin.

The effect of hemin on the stability of delta-aminolevulinate (ALA) synthase mRNA was investigated in primary cultures of chicken embryo hepatocytes. Hepatocytes were first incubated with allylisopropylacetamide (AIA) to increase the starting level of ALA synthase mRNA, and then the cells were incubated with alpha-amanitin (1 microgram/ml) to block further transcription of ALA synthase RNA. The rates of depletion of the enzyme's mRNA were then determined by liquid hybridization analyses in cells incubated with or without hemin (10 microM) in the culture medium.

Characterization of chicken liver L-alanine:4,5-dioxovaleric acid aminotransferase.

1. A procedure is described for purifying the enzyme L-alanine:4,5-dioxovaleric acid aminotransferase (DOVA transaminase) from chicken liver. The enzyme catalyzes a transamination reaction between L-alanine and 4,5-dioxovaleric acid (DOVA), yielding delta-aminolevulinic acid (ALA).

Coordinate elevations of liver delta-aminolevulinate synthase and cytochrome P-450 RNA by phenobarbital in chicken embryos: the effects of heme.

1. The role of heme in the coordinate elevations of liver delta-aminolevulinate (ALA) synthase activity and microsomal cytochrome P-450 concentration induced by phenobarbital (PB) was investigated in the chicken embryo. 2.

Regulation of biogenesis of liver delta-aminolevulinate synthase: effects of structural modifications of heme on the enzyme's RNA.

1. The aim of this study was to determine the effects of several metallo-porphyrins, derived by modifications of heme, on the concentration delta-aminolevulinate (ALA) synthase RNA in hepatocytes. 2.

Properties of chicken erythrocyte delta-aminolevulinate synthase.

A procedure is described for preparing a fraction highly enriched for chicken blood delta-aminolevulinate synthase (ALA-S) using animals recovering from acetylphenylhydrazine-induced anemia. 1. Blood cells collected from chickens recovering from anemia were disrupted by nitrogen cavitation, and the mitochondrial fraction was prepared from the cell homogenates.

Maturation of embryonic chick liver delta-aminolevulinate synthase: precursor pools and regulation by intra-cellularly produced heme.

1. Immunoblot analyses were carried out to determine the relative distributions of delta-aminolevulinate synthase (ALA synthase) in mitochondrial and cytosol fractions prepared from embryos at different times after injections with allylisopropylacetamide (AIA). 2.

Biogenesis of embryonic chick liver delta-aminolevulinate synthase: regulation of the level of mRNA by hemin.

The effects of hemin on the concentration of the mRNA for delta-aminolevulinate synthase (ALA synthase) and on the association of the messenger with polysomes were investigated in primary cultures of embryonic chick hepatocytes incubated with allylisopropylacetamide (AIA). A synthetic 24-mer DNA complementary to ALA synthase mRNA was used to determine by solution hybridization the effects of AIA and of AIA plus hemin on the ALA synthase-specific RNA sequences in the cells. The results indicated that ALA synthase mRNA concentrations increased significantly in hepatocytes incubated for 5 h with AIA (0.

Regulation of production of embryonic chick liver delta-aminolevulinate synthase: effects of testosterone and of hemin on the mRNA of the enzyme.

The effects of testosterone and of hemin on the concentration of the mRNA of embryonic chick liver ALA synthase were investigated. Using cDNA-RNA liquid hybridization analyses, we determined that testosterone, when injected into the fluid surrounding chick embryos, caused a dose-dependent increase in the concentration of ALA synthase mRNA in liver. Similarly, addition of testosterone (5 micrograms/ml) or of 75 micrograms/ml of allylisopropylacetamide (AIA) into the medium of chick embryo hepatocytes maintained in culture caused an increase in the concentration of ALA synthase mRNA.

Biogenesis of liver delta-aminolevulinate synthase. The role of cAMP in the induction.

In primary cultures of chick embryo hepatocytes pulse labeled with [35S]methionine, immunochemical analyses indicated that adenosine 3':5'-cyclic monophosphate (cAMP) did not affect either the rate of production or the maturation of delta-aminolevulinate synthase (ALA synthase). In addition, allylisopropylacetamide caused a slight drop in intracellular cAMP while testosterone caused the levels of cAMP to rise to 260% of the basal levels measured in hepatocytes in culture. Thus the results of this study did not indicate a direct short-term role for cAMP in the regulation of production of ALA synthase.

Biogenesis of mitochondrial proteins. Regulation of production of delta-aminolaevulinate synthase by haemin in embryonic-chick liver.

The effect of haemin on the biogenesis of delta-aminolaevulinate synthase (ALA synthase) was investigated in primary cultures of embryonic-chick liver. The activity of the enzyme and the amount of the enzyme detected by 'immune-blotting' were determined in hepatocytes incubated with the porphyrogenic agent allylisopropylacetamide. The results of these studies indicated that the loss in ALA synthase activity in cells incubated in the presence of haemin (10 microM) was roughly proportional to a loss in the immune-reactive mass of the enzyme.

Biogenesis of mitochondrial proteins regulation of maturation of delta-aminolevulinate synthase by hemin.

The effect of hemin on the biogenesis of delta-aminolevulinate (ALA) synthase was examined in primary cultures of chick embryo hepatocytes. Hemin (0.010 mM) in the culture medium significantly inhibited the induction of ALA synthase activity in hepatocytes exposed to the porphyrogenic agent allylisopropylacetamide.

Isolation of the mature subunit of delta-aminolaevulinate synthase from embryonic chick liver.

We presented evidence indicating that the established procedure for purifying delta-aminolaevulinate (ALA) synthase from embryonic-chick liver yielded an enzyme with a partially degraded subunit of molecular weight 51000 [Ades & Harpe (1981) J. Biol. Chem.

Transport of newly synthesized proteins into mitochondria - a review.

This review examines the mechanism of translocation of cytoplasmically synthesized proteins into mitochondria. Approximately 10% of the mitochondrial proteins are synthesized within the organelles while most mitochondrial proteins are coded for by nuclear genes and synthesized on cytoplasmic ribosomes. Those mitochondrial proteins synthesized on cytoplasmic ribosomes have to be transferred at some point into one of the mitochondrial compartments, a process which would require their insertion through one or both mitochondrial membranes.

Biogenesis of mitochondrial proteins. Identification of the mature and precursor forms of the subunit of delta-aminolevulinate synthase from embryonic chick liver.

The purpose of this study was to determine the molecular weights of the mature subunit of embryonic chick liver delta-aminolevulinate synthase and of its putative precursor fom. Although an active enzyme with a subunit molecular weight of 51,000 could be purified from the livers of porphyric embryos, it was determined by immunoreplicate electrophoresis analyses of sodium dodecyl sulfate-solubilized liver homogenates and mitochondria from porphyric embryos that the actual molecular weight of the enzyme's subunit was 65,000 +/- 2,000. These results suggested that the usual procedure for purifying delta-aminolevulinate synthase from chick embryo yielded a partially degraded enzyme.

The transport of proteins into yeast mitochondria. Kinetics and pools.

By double isotope pulse-labeling of yeast cells, we determined the kinetics of labeling at 9 degrees C of total mitochondrial membrane, mitochondrial matrix, and cytosolic proteins, the alpha, beta, and gamma subunits of F1 ATPase, and glyceraldehyde-3-phosphate dehydrogenase. We find that none of the mitochondrial proteins show a lag in the incorporation of label compared to cytosolic proteins. These results argue against the existence in the cytosol of large pools of mitochondrial proteins awaiting transport into the organelle.

The products of mitochondria-bound cytoplasmic polysomes in yeast.

Experiments were undertaken to examine the fate and composition of polypeptides synthesized on cytoplasmic polysomes associated with the outer mitochondrial membrane of Saccharomyces cerevisiae. Mitochondria with their associated cytoplasmic polysomes were isolated from growing yeast spheroplasts and placed in a polypeptide chain completion system together with [35S]methionine. Of the total products synthesized in the readout system, 80 to 85% remain associated with the mitochondria after sucrose gradient centrifugation.