Concurrent interactions of heme and FLU with Glu tRNA reductase (HEMA1), the target of metabolic feedback inhibition of tetrapyrrole biosynthesis, in dark‐ and light‐grown Arabidopsis plants
- 6 December 2004
- journal article
- Published by Wiley in The Plant Journal
- Vol. 40 (6) , 957-967
- https://doi.org/10.1111/j.1365-313x.2004.02262.x
Abstract
The regulation of tetrapyrrole biosynthesis in higher plants has been attributed to metabolic feedback inhibition of Glu tRNA reductase by heme. Recently, another negative regulator of tetrapyrrole biosynthesis has been discovered, the FLU protein. During an extensive second site screen of mutagenized flu seedlings a suppressor of flu, ulf3, was identified that is allelic to hy1 and encodes a heme oxygenase. Increased levels of heme in the hy1 mutant have been implicated with inhibiting Glu tRNA reductase and suppressing the synthesis of δ‐aminolevulinic acid (ALA) and Pchlide accumulation. When combined with hy1 or ulf3 upregulation of ALA synthesis and overaccumulation of protochlorophyllide in the flu mutants were severely suppressed supporting the notion that heme antagonizes the effect of the flu mutation by inhibiting Glu tRNA reductase independently of FLU. The coiled‐coil domain at the C‐terminal end of Glu tRNA reductase interacts with FLU, whereas the N‐terminal site of Glu tRNA reductase that is necessary for the inhibition of the enzyme by heme is not required for this interaction. The interaction with FLU is specific for the Glu tRNA reductase encoded by HEMA1 that is expressed in photosynthetically active tissues. FLU seems to be part of a second regulatory circuit that controls chlorophyll biosynthesis by interacting directly with Glu tRNA reductase not only in etiolated seedlings but also in light‐adapted green plants.Keywords
This publication has 41 references indexed in Scilit:
- Macromolecular physiology of plastids XII. Tigrina mutants in barley: genetic, spectroscopic and structural characterizationHereditas, 2009
- An Arabidopsis porB porC double mutant lacking light‐dependent NADPH:protochlorophyllide oxidoreductases B and C is highly chlorophyll‐deficient and developmentally arrestedThe Plant Journal, 2003
- Loss of Nuclear Gene Expression during the Phytochrome A-Mediated Far-Red Block of Greening ResponsePlant Physiology, 2002
- Modification of Distinct Aspects of Photomorphogenesis via Targeted Expression of Mammalian Biliverdin Reductase in Transgenic Arabidopsis PlantsPlant Physiology, 1999
- D1‐D2 protein degradation in the chloroplastEuropean Journal of Biochemistry, 1999
- Feedback Inhibition of Chlorophyll Synthesis in the Phytochrome Chromophore-Deficientaureaandyellow-green-2Mutants of TomatoPlant Physiology, 1999
- Phytochrome-Deficient hy1 and hy2 Long Hypocotyl Mutants of Arabidopsis Are Defective in Phytochrome Chromophore BiosynthesisPlant Cell, 1991
- Photodynamic herbicides. Recent developments and molecular basis of selectivityCritical Reviews in Plant Sciences, 1988
- Genetic Regulation of Chlorophyll Synthesis Analyzed with Mutants in BarleyScience, 1974
- A Revised Medium for Rapid Growth and Bio Assays with Tobacco Tissue CulturesPhysiologia Plantarum, 1962