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Var2 mutation in Arabidopsis affects D1 degradation

Var2 mutation in Arabidopsis affects D1 degradation

Bailey, S., Thompson, E.P. ORCID: 0000-0002-6434-9290, Mullineaux, C.W., Nixon, P., Robinson, C. and Mann, N. (2001) Var2 mutation in Arabidopsis affects D1 degradation. Biochemical Society Transactions, 29 (3). A67-A67. ISSN 0300-5127 (Print), 1470-8752 (Online) (doi:

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Var2 is one of several FtsH homologues in Arabidopsis thaliana. Var2 mutations cause variegation, and alter photosynthetic function in a number of ways. FtsH proteins are AAA proteases (ATPases associated with a variety of cellular activities), which are widely distributed in prokaryotes and eukaryotes and have numerous roles. We have found that Var2 mutant are affected in the D1 repair cycle following photoinhibition. Composition of the photosynthetic apparatus is comparable in wild-type (WT). The chlorophyll a/b ratios suggest similar-size photosystem (PS) I1 antennae, and fluorescence spectra indicate only slightly different PS1:PSII ratios in low-light-grown plants. Measurement of Fv/Fm, however, suggests that Var2 undergoes greater photoinhibition than WT at low (300 kE/mZ/s) and, markedly, high light (1800 pE/mZ/s). When protein synthesis is prevented (with lincomycin), both Var2 and WT leaves are photoinhibited at high light since neither can synthesise new D1 polypeptide following photooxidative damage. Even without lincomycin, however, Var2 is photoinhibited to twice the extent of WT this key PSII protein is not replaced. Western blots confirm that lincomycin-treated WT leaves exhibit rapid D1 turnover whereas Var2 leaves do not, suggesting that D1 is not degraded.

Item Type: Article
Additional Information: 673rd Bristol Meeting Tuesday 10 April; Wednesday 11 April Speaker Abstract
Uncontrolled Keywords: Var2, FtsH, metalloprotease, Arabidopsis, photosynthesis
Subjects: Q Science > Q Science (General)
Q Science > QH Natural history > QH301 Biology
Faculty / School / Research Centre / Research Group: Faculty of Education, Health & Human Sciences > School of Human Sciences (HUM)
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Last Modified: 09 Oct 2021 04:46

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