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The first committed step in the biosynthesis of L-ascorbate from D-glucose in plants requires conversion of GDP-L-galactose to L-galactose 1-phosphate by a previously unidentified enzyme. Here we show that the protein encoded by VTC2, a gene mutated in vitamin C-deficient Arabidopsis thaliana strains, is a member of the GalT/Apa1 branch of the histidine(More)
Insulin-like growth factor I (IGF-I) is required for normal embryonic development and postnatal growth. Like most hormones and growth factors, IGF-I is synthesized as a proprotein that is converted to the mature form by endoproteolysis. Processing of pro-IGF-I to mature IGF-I occurs by cleavage within the unique pentabasic processing motif(More)
A library of 50,000 recombinants representative of the human X chromosome has been constructed. Human X chromosomes were physically separated using a fluorescence-activated cell sorter. The DNA was purified from the chromosomes, digested to completion with the restriction enzyme EcoRI and cloned into the phage lambda gtWES.lambda B. The X-derived nature of(More)
Radioactively labelled DNAs (5 X 10(6) cpm/mug) complementary to human 18 S and 28 S ribosomal RNA were synthesized using RNA-directed DNA polymerase (EC These complementary DNAs were used to measure human ribosomal gene numbers by two independent methods, both of which indicated numbers at least four-fold lower than those previously reported.(More)
  • B D Young
  • 1984
The latest developments in the application of flow cytometry to the analysis and fractionation of metaphase chromosomes is reviewed. This includes the preparative techniques, staining and machine technology used in flow karyotype production. In particular, the application of this technology to the study of chromosomal changes and to the construction of(More)
The random association of Epstein-Barr virus DNA with host cell metaphase chromosomes of all sizes in Burkitt's lymphoma-derived cell lines was demonstrated by two substantially different techniques, namely fluorescence-activated chromosome sorting and in situ hybridization. The nature and potential importance of this association are discussed.
Base sequence complexities of polysomal poly(A+)RNA from mouse embryo, brain, and liver have been estimated by hybridization to homologous cDNA to be approximately 7 x 109, 1.5 x 1010, and 7 x109 daltons, respectively. By annealing each cDNA with a large excess of total mouse embryo DNA, the genes coding for the polysomal poly(A+) sequences were shown to be(More)
Conditions are described under which poly(A) polymerase from Escherichia coli ribosomes will catalyse the addition of AMP residues onto the 3'-ends of human 18 S and 28 S ribosomal RNAs at an average rate of 40 AMP residues per 1000 nucleotides in 20 min. Single-stranded complementary DNAs (cDNAs) can then be transcribed from the polyadenylated RNAs with(More)