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The neutral amino acid transport systems A, ASC, and L have been characterized in the Chinese hamster ovary cell. System A, defined by its sodium ion dependency and inhibition by 2-methylaminoisobutyric acid, was found to be extremely sensitive to the pH of the external medium and to increase in response to starvation for amino acids. System ASC, identified(More)
Zeins, the storage proteins of maize, are totally lacking in the essential amino acids lysine and tryptophan. Lysine codons and lysine- and tryptophan-encoding oligonucleotides were introduced at several positions into a 19-kilodalton zein complementary DNA by oligonucleotide-mediated mutagenesis. A 450-base pair open reading frame from a simian virus 40(More)
We employed a rapid fractionation method coupled with a sensitive enzyme-linked immunosorbent assay to quantify the globulins and avenins in developing and mature oat seeds. On a molar basis, there is approximately 10-11 times as much globulin as avenin. Pulse labeling of endosperm proteins indicated that the rate of globulin synthesis is approximately nine(More)
We have isolated genomic clones encoding the two major classes of seed storage proteins in oats, the 12 S globulins and the avenins. The globulin genes encode glutamine-rich, sulfur-poor storage proteins that are highly conserved in sequence and structure. The globulin genes contain three short introns whose positions in the coding sequence are the same as(More)
We have isolated and characterized cDNA clones encoding avenins, the prolamine storage proteins of oat seeds. Sequence analysis shows that avenins are a related group of polypeptides and that their mRNAs differ from each other by point mutations and small insertions and deletions. Avenin proteins have structural homology to the alpha/beta-gliadins and(More)
The regulation of the activity of transport System L for neutral amino acids has been investigated in Chinese hamster ovary cells. Incubation of the temperature-sensitive leucyl-tRNA synthetase mutant CHO-tsH1 at marginally permissive temperatures results in leucine-limited growth and increased transport of branched chain and aromatic amino acids. This(More)
We have isolated full-length cDNA clones that encode oat (Avena sativa) seed storage globulin mRNAs from a cDNA library in the expression vector lambda gtll. The longest of these clones, pOG2, has an 1840-base pair insert that encodes a complete precursor subunit with a signal peptide of 24 amino acids followed by an acidic polypeptide of 293 amino acids(More)
Five Arabidopsis mutants have been isolated on the basis of hypersensitivity of leaf tissue to UV light. For each mutant, the UV-hypersensitive phenotype (uvh) was inherited as a single recessive Mendelian trait. In addition, each uvh mutant represented a separate complementation group. Three of the mutations producing the UV hypersensitive phenotype have(More)