Abstract
We identified Arabidopsis mutant SS93 having short root. SS93 shows disorganization of cell layers not only in RAM but also in SAM, abnormal phyllotaxy and leaf morphology, and fasciated stem. We mapped SS93 mutation on chromosome4 by using genome information and found a deletion of 2.7kb in a gene which may encode a protein with the polymerase domains of prokaryotic DNA polymerases and conserved motifs characteristic of helicases. Proteins having these two structures were previously identified in various eukaryotes. Mutation in the Drosophila homolog, mus308, gene confer specific hypersensitivity to DNA-crosslinking agents as a consequence of defects in DNA repair. SS93 phenocopies fasciata (fas) mutant which shows abnormal meristem structures. FASCIATA gene encodes a subunit of the Arabidopsis counterpart of chromatin assembly factor-1 (CAF-1), and previous studies in animals show that CAF-1 is involved in DNA repair and replication. It seems that SS93 and fas have common defect in replication.
