Chloroplast development at low temperatures requires a homolog of DIM1, a yeast gene encoding the 18S rRNA dimethylase.
Poikilothermic organisms require mechanisms that allow survival at chilling temperatures (2 to 15 degreesC). We have isolated chilling-sensitive mutants of Arabidopsis, a plant that is very chilling resistant, and are characterizing them to understand the genes involved in chilling resistance. The T-DNA-tagged mutant paleface1 (pfc1) grows normally at 22 degrees C but at 5 degrees C exhibits a pattern of chilling-induced chlorosis consistent with a disruption of chloroplast development. Genomic DNA flanking the T-DNA was cloned and used to isolate wild-type genomic and cDNA clones. The PFC1 transcript is present at a low level in wild-type plants and was not detected in pfc1 plants. Wild-type Arabidopsis expressing antisense constructs of PFC1 grew normally at 22 degrees C but showed chilling-induced chlorosis, confirming that the gene is essential for low-temperature development of chloroplasts. The deduced amino acid sequence of PFC1 has identity with rRNA methylases found in bacteria and yeast that modify specific adenosines of pre-rRNA transcripts. The pfc1 mutant does not have these modifications in the small subunit rRNA of the plastid.
Tokuhisa
J G
JG
Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340, USA.
Vijayan
P
P
Feldmann
K A
KA
Browse
J A
JA
D000064:Acclimatization; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000502:physiology*; D029681:Arabidopsis Proteins; D001483:Base Sequence; D002736:Chloroplasts / Q000502:physiology*; D003080:Cold Temperature; D017124:Conserved Sequence; D004269:DNA, Bacterial / Q000235:genetics; D005800:Genes, Fungal; D017343:Genes, Plant; D008780:Methyltransferases / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D010940:Plant Proteins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013696:Temperature
D029681:Arabidopsis Proteins; D004269:DNA, Bacterial; D010940:Plant Proteins; D029701:Saccharomyces cerevisiae Proteins; C036483:T-DNA; C088929:DIM1 protein, S cerevisiae; D008780:Methyltransferases; C112639:PFC1 protein, Arabidopsis