Références sur les Plantes

demonstrating that it is a component of the 80S ribosome. Previously, ultraviolet-B (UV-B) exposure was shown to increase the expression of a number of maize ribosomal protein genes, including rpl10. In this work, we demonstrate that maize rpl10 genes are induced by UV-B while Arabidopsis RPL10s are differentially regulated by this radiation: RPL10A is not UV-B regulated, RPL10B is down-regulated, while RPL10C is upregulated by UV-B in all organs studied. Characterization of Arabidopsis T-DNA insertional mutants indicates that RPL10 genes are not functionally equivalent. rpl10A and rpl10B mutant plants show different phenotypes: knockout rpl10A mutants are lethal, rpl10A heterozygous plants are deficient in translation under UV-B conditions, and knockdown homozygous rpl10B mutants show abnormal growth. Based on the results described here, RPL10 genes are not redundant and participate in development and translation under UV-B stress.

URL: http://www.plantphysiol.org/cgi/content/abstract/153/4/1878 Author Address: Centro de Estudios Fotosintéticos y Bioquímicos, Universidad Nacional de Rosario, Suipacha 531, Rosario, Argentina Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94158–2517 USA XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX Author: Fields Allison, Wang Ning, Hua Zhihua, Meng Xiaoying, Kao Teh-hui, Year: 2010 Title: * Functional characterization of two chimeric proteins between a Petunia inflataS-locus F-box protein, PiSLF2, and a PiSLF-like protein, PiSLFLb-S2 .

Secondary Title: Plant Molecular Biology 74, 3, 279-292.

Publisher: Springer Netherlands Date: 2010-10-01 ISBN/ISSN: 0167-4412 Label: Physiol Keywords: Biomedical and Life Sciences - Chimeric proteins - Petunia inflata - Self-incompatibility - Slocus F-box protein - S-RNase Abstract: Self-incompatible solanaceous species possess the S-RNase and SLF (S-locus F-box) genes at the highly polymorphic S-locus, and their products mediate S-haplotype-specific rejection of pollen tubes in the style. After a pollen tube grows into the style, the S-RNases produced in the style are taken up; however, only self S-RNase (product of the matching S-haplotype) can inhibit the subsequent growth of the pollen tube. Based on the finding that non-self interactions between PiSLF (Petunia inflata SLF) and S-RNase are stronger than self-interactions, and based on the biochemical properties of PiSLF, we previously proposed that a PiSLF preferentially interacts with its non-self S-RNases to mediate their ubiquitination and degradation, thereby only allowing self S-RNase to exert its cytotoxic function. We further divided PiSLF into three potential Functional Domains (FDs), FD1-FD3, based on sequence comparison of PiSLF and PiSLF-like proteins, and based on SRNase-binding properties of these proteins and various truncated forms of PiSLF2 (S 2 allelic variant of PiSLF). In this work, we examined the in vivo function of FD2, which we proposed to be responsible for strong, general interactions between PiSLF and S-RNase. We swapped FD2 of PiSLF2 with the corresponding region of PiSLFLb-S2 (S 2 allelic variant of a PiSLF-like protein), and expressed GFP-fused chimeric proteins, named b-2-b and 2-b-2, in S 2 S 3 transgenic plants. We showed that neither chimeric protein retained the SI function of PiSLF2, suggesting that FD2 is necessary, but not sufficient, for the function of PiSLF. Moreover, since we previously found that b-2-b and 2-b-2 only interacted with S3-RNase ~50 and ~30%, respectively, as strongly as did PiSLF2 in vitro, their inability to function as PiSLF2 is also consistent with our model predicating on strong interaction between a PiSLF and its non-self S-RNases as part of the biochemical basis for S-haplotype-specific rejection of pollen tubes.

Notes: 25 Ref. URL: http://dx.doi.org/10.1007/s11103-010-9672-x Author Address: (1) Department of Biochemistry and Molecular Biology, The Pennsylvania State University, 403 Althouse Lab, University Park, PA 16802, USA (2) Intercollege Graduate Degree Program in Plant Biology, The Pennsylvania State University, 403 Althouse Lab, University Park, PA 16802, USA (3) Present address: Department of Genetics, University of Wisconsin, Madison, WI 53706, USA