OPEN ACCESS ARTICLE

This Article Free via Open Access: OA OA Full Text Full Text (PDF) Supplemental Data OA All Versions of this Article: 18/2/350    most recent tpc.105.037044v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (7) Citing Articles via Google Scholar Google Scholar Articles by Wang, C. Articles by Liu, Z. Search for Related Content PubMed PubMed Citation Articles by Wang, C. Articles by Liu, Z. Agricola Articles by Wang, C. Articles by Liu, Z.

Arabidopsis Ribonucleotide Reductases Are Critical for Cell Cycle Progression, DNA Damage Repair, and Plant Development^[W],[OA]

Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742

¹ To whom correspondence should be addressed. E-mail zliu{at}umd.edu; fax 301-314-9082.

Ribonucleotide reductase (RNR), comprising two large (R1) and two small (R2) subunits, catalyzes a rate-limiting step in the production of deoxyribonucleotides needed for DNA replication and repair. Previous studies in yeast and mammals indicated that defective RNR often led to cell cycle arrest, growth retardation, and p53-dependent apoptosis, whereas abnormally increased RNR activities led to higher mutation rates. Because plants are constantly exposed to environmental mutagens and plant cells are totipotent, an understanding of RNR function in plants is important. We isolated and characterized mutations in all three R2 genes (TSO2, RNR2A, and RNR2B) in Arabidopsis thaliana. tso2 mutants had reduced deoxyribonucleoside triphosphate (dNTP) levels and exhibited developmental defects, including callus-like floral organs and fasciated shoot apical meristems. tso2 single and tso2 rnr2a double mutants were more sensitive to UV-C light, and tso2 rnr2a seedlings exhibited increased DNA damage, massive programmed cell death, and release of transcriptional gene silencing. Analyses of single and double r2 mutants demonstrated that a normal dNTP pool and RNR function are critical for the plant response to mutagens and proper plant development. The correlation between DNA damage accumulation and the subsequent occurrence of apoptotic nuclei in tso2 rnr2a double mutants suggests that perhaps plants, like animals, can initiate programmed cell death upon sensing DNA damage.

This article has been cited by other articles:

				C. Breuer, N. J. Stacey, C. E. West, Y. Zhao, J. Chory, H. Tsukaya, Y. Azumi, A. Maxwell, K. Roberts, and K. Sugimoto-Shirasu BIN4, a Novel Component of the Plant DNA Topoisomerase VI Complex, Is Required for Endoreduplication in Arabidopsis PLANT CELL, November 1, 2007; 19(11): 3655 - 3668. [Abstract] [Full Text] [PDF]

				Y. Zhu, A. Dong, D. Meyer, O. Pichon, J.-P. Renou, K. Cao, and W.-H. Shen Arabidopsis NRP1 and NRP2 Encode Histone Chaperones and Are Required for Maintaining Postembryonic Root Growth PLANT CELL, November 1, 2006; 18(11): 2879 - 2892. [Abstract] [Full Text] [PDF]

				N. Li, D.-S. Zhang, H.-S. Liu, C.-S. Yin, X.-x. Li, W.-q. Liang, Z. Yuan, B. Xu, H.-W. Chu, J. Wang, et al. The Rice Tapetum Degeneration Retardation Gene Is Required for Tapetum Degradation and Anther Development PLANT CELL, November 1, 2006; 18(11): 2999 - 3014. [Abstract] [Full Text] [PDF]