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- Ellerström, Mats, 1961, et al.
(författare)
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Ectopic Expression of EFFECTOR OF TRANSCRIPTION Perturbs Gibberellin-Mediated Plant Developmental Processes
- 2005
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Ingår i: Plant Molecular Biology. - : Springer Science and Business Media LLC. - 0167-4412 .- 1573-5028. ; 59:4, s. 663-681
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Tidskriftsartikel (refereegranskat)abstract
- The plant hormone gibberellin (GA) is known to modulate various aspects of plant cell differentiation and development. The current model of GA-mediated regulation is based on a de-repressible system and includes specific protein modification and degradation. HRT, a zinc finger protein from barley has been shown to have GA-dependent transcriptional repressing activity on the seed-specific α-amylase promoter [Raventos, D., Skriver, K., Schlein, M., Karnahl, K., Rogers, S.W., Rogers, J.C. and Mundy, J. 1998. J.␣Biol. Chem. 273: 2331323320]. Here we report the characterization of a dicot homologue from Brassica napus (BnET) and provide evidence for its role in GA response modulation suggesting that this could be a conserved feature of this gene family. When BnET is ectopically expressed in either Arabidopsis or tobacco the phenotypes include dwarfism due to shorter internodes and late flowering, reduced germination rate, increased anthocyanin content and reduced xylem lignification as a marker for terminal cell differentiation. Transient expression in protoplasts supports the notion that this most likely is due to a transcriptional repression of GA controlled genes. Finally, histological analysis showed that in contrast to other GA deficient mutants the shorter internodes were due to fewer but not smaller cells, suggesting a function of BnET in GA-mediated cell division control.
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| 2. |
- Wycliffe, P., et al.
(författare)
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Continuous expression in tobacco leaves of a Brassica napus PEND homologue blocks differentiation of plastids and development of palisade cells
- 2005
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Ingår i: The Plant Journal. - 0960-7412 .- 1365-313X. ; 44:1, s. 1-15
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Tidskriftsartikel (refereegranskat)abstract
- Brassica napus complementary deoxyribonucleic acid (cDNA) clones encoding a DNA-binding protein, BnPEND, were isolated by Southwestern screening. A distinctive feature of the protein was a bZIP-like sequence in the amino-terminal portion, which, after expression in Escherichia coli, bound DNA. BnPEND transcripts were present in B. napus roots and flower buds, and to a lesser extent in stems, flowers and young leaves. Treatment in the dark for 72 h markedly increased the amount of BnPEND transcript in leaves of all ages. Sequence comparison showed that BnPEND was similar to a presumed transcription factor from B. napus, GSBF1, a protein deduced from an Arabidopsis thaliana cDNA (BX825084) and the PEND protein from Pisum sativum, believed to anchor the plastid DNA to the envelope early during plastid development. Homology to expressed sequence tag (EST) sequences from additional species suggested that BnPEND homologues are widespread among the angiosperms. Transient expression of BnPEND fused with green fluorescent protein (GFP) in Nicotiana benthamiana epidermal cells showed that BnPEND is a plastid protein, and that the 15 amino acids at the amino-terminal contain information about plastid targeting. Expression of BnPEND in Nicotiana tabacum from the Cauliflower Mosaic Virus 35S promoter gave stable transformants with different extents of white to light-green areas in the leaves, and even albino plants. In the white areas, but not in adjacent green tissue, the development of palisade cells and chloroplasts was disrupted. Our data demonstrate that the BnPEND protein, when over-expressed at an inappropriate stage, functionally blocks the development of plastids and leads to altered leaf anatomy, possibly by preventing the release of plastid DNA from the envelope.
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