Disruption of theAtREV3Gene Causes Hypersensitivity to Ultraviolet B Light and γ-Rays in Arabidopsis: Implication of the Presence of a Translesion Synthesis Mechanism in Plants [W]

Abstract

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 ( AtREV3 ), which is thought to be involved in translesion synthesis. The rev3-1 seedlings also were sensitive to ␥ -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.

Arabidopsis RAD51C Gene Is Important for Homologous Recombination in Meiosis and Mitosis

“…MMC inhibits both the production of true leaves and growth of roots of antisense AtRAD1 plants (Gallego et al, 2000). MMC also inhibits the root growth of the rev3 mutant plant, although the effect of MMC on the production of true leaves has not been determined (Sakamoto et al, 2002). These results suggest that the contribution of HR repair to the cross-linked DNA repair might be tissue specific, although the cooperation of several DNA repair pathways must be operational for the efficient repair of cross-linked DNAs in plant cells.…”

“…According to studies on yeast and mammals, damaged DNA by cross-linking reagents such as cisplatin and mitomycin C (MMC) is repaired through three potential repair pathways: nucleotide excision repair (NER), postreplication repair/translesion DNA synthesis, and HR repair (Dronkert and Kanaar, 2001). Other than mutants of HR factor, two mutants and antisense-suppressed plants show higher sensitivity to the cross-linking reagents: antisense AtRAD1 (NER factor; Gallego et al, 2000) and atrev3 (translesion DNA synthesis factor; Sakamoto et al, 2002). MMC inhibits both the production of true leaves and growth of roots of antisense AtRAD1 plants (Gallego et al, 2000).…”

DNA polymerase zeta (pol ζ) in higher eukaryotes

“…Arabidopsis carrying a mutation in Rev3 are viable, but root growth is hypersensitive to ultraviolet-B radiation (313 nm), with stem cells in the root being particularly sensitive to inactivation by such radiation [89,90]. Arabidopsis with the mutant Rev3 were also more sensitive than normal plants to mitomycin C and to ionizing radiation [89]. Disruption of the Arabidopsis Rev1 and Rev7 genes has also been performed [91].…”

Role of AtPolζ, AtRev1, and AtPolη in UV Light-Induced Mutagenesis in Arabidopsis

“…AtPolh, encoded by AtPOLH, bypasses cyclobutane pyrimidine dimers with comparable activity to human or yeast Polh (Anderson et al, 2008;Hoffman et al, 2008). AtREV3-, AtREV7-, AtREV1-, or AtPOLH-disrupted plants are more sensitive to UV light exposure compared with wild-type plants, although the levels of sensitivity differ (Sakamoto et al, 2003;Takahashi et al, 2005;Curtis and Hays, 2007;Anderson et al, 2008), suggesting that these genes play a role in conferring tolerance to UV light-induced damage.…”

“…In Arabidopsis (Arabidopsis thaliana), we and other groups have isolated several genes encoding TLS-type polymerase homologs: AtREV3, AtREV7, AtREV1, AtPOLH, and AtPOLK (Sakamoto et al, 2003;García-Ortiz et al, 2004;Takahashi et al, 2005;Santiago et al, 2006). AtREV3 and AtREV7 encode a catalytic subunit and a regulatory subunit of AtPolz, respectively.…”