Abstract
TEBICHI (TEB) gene of Arabidopsis encodes a homolog of animal MUS308/POLQ proteins which are involved in DNA damage response, and loss-of-function teb mutants show defects in morphology of meristems and organs. teb showed constitutively activated DNA damage responses and an accumulation of cells expressing G2/M-specific cyclinB1;1:GUS in meristems. We show here that this accumulation of cyclinB1;1:GUS-expressing cells in teb was suppressed by a disruption of ATR gene which is involved in DNA replication checkpoint, suggesting teb is defective in DNA replication and activates ATR-dependent checkpoint. However atr enhanced morphological phenotypes of teb. Furthermore, teb atr double mutants frequently developed needle-like leaves indicating teb atr is defective in adaxial-abaxial polarity of leaves. Histochemical analysis of leaf cells and expression analysis of abaxial-specific FILAMENTOUS FLOWER gene showed leaves of teb and teb atr were partially abaxialized, indicating TEB is involved in the establishment of adaxial-abaxial polarity of leaves.
