Abstract:
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To investigate UV light response mechanisms in higher plants, we isolated a UV light-sensitive
mutant, rev3-1, in Arabidopsis. The root growth of rev3-1 was inhibited after UV-B irradiation under both
light and dark conditions. We found that chromosome 1 of rev3-1 was broken at a minimum of three points,
causing chromosome inversion and translocation. A gene disrupted by this rearrangement encoded the
catalytic subunit of DNA polymerase ζ (AtREV3), which is thought to be involved in translesion synthesis.
The rev3-1 seedlings also were sensitive to γ-rays and mitomycin C, which are known to inhibit DNA
replication. Incorporation of bromodeoxyuridine after UV-B irradiation was less in rev3-1 than in the wild
type. These results indicate that UV light-damaged DNA interrupted DNA replication in the rev3-1 mutant,
leading to the inhibition of cell division and root elongation |