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Pierre Poutrain Gr��gory Guirimand Ga?lle Gl��varec Vincent Courdavault Olivier Pichon 《Journal of Plant Growth Regulation》2011,30(2):235-241
In Catharanthus roseus cells, auxins are known to negatively regulate the biosynthesis of monoterpenoid indole alkaloids (MIA), a class of valuable
secondary metabolites. Despite extensive studies of this regulation, no protein of the auxin signaling pathway has been isolated
to date in this plant. We therefore decided to clone and characterize a C. roseus Aux/IAA protein that belongs to a family of gene expression repressors mediating auxin effects. Using PCR, a cDNA encoding
the first C. roseus Aux/IAA was cloned and named CrIAA1. The deduced amino acid sequence has four highly conserved domains that are typical of the Aux/IAA protein family and has
high homology to the Aux/IAA isoforms of Arabidopsis (>67%). The CrIAA1 gene expression, monitored by real-time PCR, was found to be dramatically induced by auxin treatment in C. roseus cells. Using GFP imagery and a bimolecular fluorescence complementation assay, we found that CrIAA1 can form oligomers in
the nucleus. We also found that CrIAA1 is quickly degraded following auxin treatments, suggesting that auxin regulates CrIAA1
availability via a feedback mechanism. These results should help to elucidate the molecular nature of the processes responsible
for the auxin-mediated regulation of MIA biosynthesis in C. roseus. 相似文献
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A. M. Middleton J. R. King M. J. Bennett M. R. Owen 《Bulletin of mathematical biology》2010,72(6):1383-1407
The hormone auxin is implicated in regulating a diverse range of developmental processes in plants. Auxin acts in part by
inducing the Aux/IAA genes. The associated pathway comprises multiple negative feedback loops (whereby Aux/IAA proteins can repress Aux/IAA genes) that are disrupted by auxin mediating the turnover of Aux/IAA protein. In this paper, we develop a mathematical model
of a single Aux/IAA negative feedback loop in a population of identical cells. The model has a single steady-state. We explore parameter space
to uncover a number of dynamical regimes. In particular, we identify the ratio between the Aux/IAA protein and mRNA turnover
rates as a key parameter in the model. When this ratio is sufficiently small, the system can evolve to a stable limit cycle,
corresponding to an oscillation in Aux/IAA expression levels. Otherwise, the steady-state is either a stable-node or a stable-spiral. These observations may shed light
on recent experimental results. 相似文献
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Yi Su Weigui Luo Xiaofei Chen Huizhen Liu Yueqing Hu Wanhuang Lin Langtao Xiao 《Biological procedures online》2017,19(1):1