crinkled leaves 8--a mutation in the large subunit of ribonucleotide reductase--leads to defects in leaf development and chloroplast division in Arabidopsis thaliana.
The crinkled leaves8 (cls8) mutant of Arabidopsis thaliana displays a developmental phenotype of abnormal leaf and flower morphology, reduced root growth and bleached leaf sections. Map-based cloning identified the mutation as being within the gene encoding the large subunit of ribonucleotide reductase (RNR1), the enzyme that catalyses the rate-limiting step in the production of deoxyribonucleoside triphosphates (dNTPs) for DNA synthesis and repair. Levels of dTTP and dATP were significantly reduced in cls8. Two further mutant cls8 alleles and cls8::RNAi plants show similar or more severe phenotypes. The cls8-1 mutant has fewer copies of the chloroplast genome, and fewer, larger chloroplasts than wild-type plants. The ultrastructure of the chloroplast, however, appears normal in cls8-1 leaves. We present evidence that, under conditions of limited dNTP supply, the inhibition of chloroplast DNA replication may be the primary factor in inducing aberrant growth.
Garton
Sarah
S
School of Biological Sciences, Royal Holloway, University of London, Egham, Surrey TW20 0EX, UK.
Knight
Heather
H
Warren
Gareth J
GJ
Knight
Marc R
MR
Thorlby
Glenn J
GJ
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D002736:Chloroplasts / Q000502:physiology*; D003001:Cloning, Molecular; D018548:Cotyledon / Q000235:genetics / Q000254:growth & development; D018506:Gene Expression Regulation, Plant; D005838:Genotype; D018525:Germination / Q000235:genetics / Q000502:physiology; D046529:Microscopy, Electron, Transmission; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D018515:Plant Leaves / Q000235:genetics* / Q000254:growth & development / Q000648:ultrastructure; D030821:Plants, Genetically Modified; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D012264:Ribonucleotide Reductases / Q000235:genetics* / Q000378:metabolism; D036226:Seedlings / Q000235:genetics / Q000254:growth & development; D017386:Sequence Homology, Amino Acid; D013942:Thymine Nucleotides / Q000378:metabolism
D029681:Arabidopsis Proteins; D021122:Protein Subunits; D013942:Thymine Nucleotides; D012264:Ribonucleotide Reductases; C024157:thymidine 5'-triphosphate