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First published online October 1, 2004; 10.1104/pp.104.047043 Plant Physiology 136:3319-3332 (2004) © 2004 American Society of Plant Biologists Crosslinking of Ribosomal Proteins to RNA in Maize Ribosomes by UV-B and Its Effects on Translation1,[w]Department of Biological Sciences, Stanford University, Stanford, California 943055020
Ultraviolet-B (UV-B) photons can cause substantial cellular damage in biomolecules, as is well established for DNA. Because RNA has the same absorption spectrum for UV as DNA, we have investigated damage to this cellular constituent. In maize (Zea mays) leaves, UV-B radiation damages ribosomes by crosslinking cytosolic ribosomal proteins S14, L23a, and L32, and chloroplast ribosomal protein L29 to RNA. Ribosomal damage accumulated during a day of UV-B exposure correlated with a progressive decrease in new protein production; however, de novo synthesis of some ribosomal proteins is increased after 6 h of UV-B exposure. After 16 h without UV-B, damaged ribosomes were eliminated and translation was restored to normal levels. Ribosomal protein S6 and an S6 kinase are phosphorylated during UV-B exposure; these modifications are associated with selective translation of some ribosomal proteins after ribosome damage in mammalian fibroblast cells and may be an adaptation in maize. Neither photosynthesis nor pigment levels were affected significantly by UV-B, demonstrating that the treatment applied is not lethal and that maize leaf physiology readily recovers.
1 This work was supported by the National Science Foundation (grant no. IBN 9872657) and the U.S. Department of Agriculture (grant no. 200300745). P.C. was a postdoctoral fellow of Fundación Antorchas. [w] The online version of this article contains Web-only data. Article, publication date, and citation information can be found at www.plantphysiol.org/cgi/doi/10.1104/pp.104.047043. * Corresponding author; e-mail pcasati{at}stanford.edu; fax 6507258221. Received May 25, 2004; returned for revision August 17, 2004; accepted August 17, 2004. This article has been cited by other articles:
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