Thi1, a thiamine biosynthetic gene in Arabidopsis thaliana, complements bacterial defects in DNA repair.
An Arabidopsis thaliana cDNA was isolated by complementation of the Escherichia coli mutant strain BW535 (xth, nfo, nth), which is defective in DNA base excision repair pathways. This cDNA partially complements the methyl methane sulfonate (MMS) sensitive phenotype of BW535. It also partially corrects the UV-sensitive phenotype of E. coli AB1886 (uvrA) and restores its ability to reactivate UV-irradiated lambda phage. It has an insert of ca. 1.3 kb with an open reading frame of 1047 bp (predicting a protein with a molecular mass of 36 kDa). This cDNA presents a high homology to a stress related gene from two species of Fusarium (sti35) and to genes whose products participate in the thiamine biosynthesis pathway, THI4, from Saccharomyces cerevisiae and nmt2 from Schizosaccharomyces pombe. The Arabidopsis predicted polypeptide has homology to several protein motifs: amino-terminal chloroplast transit peptide, dinucleotide binding site, DNA binding and bacterial DNA polymerases. The auxotrophy for thiamine in the yeast thi4::URA3 disruption strain is complemented by the Arabidopsis gene. Thus, the cloned gene, named thi1, is likely to function in the biosynthesis of thiamine in plants. The data presented in this work indicate that thi1 may also be involved in DNA damage tolerance in plant cells.
Machado
C R
CR
Depto. de Biologia, Universidade de São Paulo, Brazil.
de Oliveira
R L
RL
Boiteux
S
S
Praekelt
U M
UM
Meacock
P A
PA
Menck
C F
CF
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism*; D029681:Arabidopsis Proteins; D010582:Bacteriophage lambda / Q000235:genetics / Q000528:radiation effects*; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000096:biosynthesis* / Q000737:chemistry* / Q000235:genetics; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics* / Q000528:radiation effects; D005670:Fusarium / Q000235:genetics; D015723:Gene Library; D017343:Genes, Plant; D005816:Genetic Complementation Test; D008741:Methyl Methanesulfonate / Q000494:pharmacology; D008969:Molecular Sequence Data; D016296:Mutagenesis; D010641:Phenotype; D012568:Schizosaccharomyces / Q000235:genetics / Q000254:growth & development; D017386:Sequence Homology, Amino Acid; D013831:Thiamine / Q000096:biosynthesis*; D014157:Transcription Factors / Q000096:biosynthesis* / Q000737:chemistry* / Q000235:genetics; D014466:Ultraviolet Rays
D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; C437085:THI1 protein, Arabidopsis; D014157:Transcription Factors; D008741:Methyl Methanesulfonate; D013831:Thiamine