arabinose kinase, ARA1, gene of Arabidopsis is a novel member of the galactose kinase gene family

• Published in: Plant molecular biology 1999-03, Vol.39 (5), p.1003-1012
• Main Authors: Sherson, S, Gy, I, Medd, J, Schmidt, R, Dean, C, Kreis, M, Lecharny, A, Cobbett, C
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; amino acid sequences; Amino acids; ara1 gene; Arabidopsis - chemistry; Arabidopsis - enzymology; Arabidopsis - genetics; Arabidopsis Proteins; Arabidopsis thaliana; chromosome mapping; Chromosome Walking; Cloning; Cloning, Molecular; complementary DNA; DNA, Complementary - chemistry; DNA, Complementary - genetics; DNA, Plant - chemistry; DNA, Plant - genetics; E coli; enzyme activity; Galactokinase - genetics; genbank/af024623; Genes; Genes, Plant - genetics; genetic complementation; Genetic Complementation Test; genetic transformation; Kinases; Molecular Sequence Data; mutants; nucleotide sequences; open reading frames; Phosphotransferases (Alcohol Group Acceptor) - genetics; Physical Chromosome Mapping; restriction mapping; Sequence Analysis, DNA; Sequence Homology, Amino Acid; structural genes; Transgenic plants
• ISSN: 0167-4412; 1573-5028
• DOI: 10.1023/A:1006181908753

The arabinose-sensitive ara1-1 mutant of Arabidopsis is deficient in arabinose kinase activity. A candidate for the ARA1 gene, ISA1, has been previously identified through the Arabidopsis genome sequencing initiative. Here we demonstrate that (1) the ARA1 gene coincides with ISA1 in a positional cloning strategy; (2) there are mutations in the ISA1 gene in both the ara1-1 mutant and an intragenic suppressor mutant; and (3) the ara1-1 and suppressor mutant phenotypes can be complemented by the expression of the ISA1 cDNA in transgenic plants. Together these observations confirm that ISA1 is the ARA1 gene. ARA1 is a member of the galactose kinase family of genes and represents a new substrate specificity among this and other families of sugar kinases. A second gene with similarities to members of the galactose kinase gene family has been identified in the EST database. A 1.8 kb cDNA contained an open reading-frame predicted to encode a 496 amino acid polypeptide. The GAL1 cDNA was expressed in a galK mutant of Escherichia coli and in vitro assays of extracts of the strain expressing GAL1 confirmed that the cDNA encodes a galactose kinase activity. Both GAL1 and ARA1 cross-hybridise at low stringency to other sequences suggesting the presence of additional members of the galactose kinase gene family.