Overexpression of chloroplast-targeted ferrochelatase 1 results in a genomes uncoupled chloroplast-to-nucleus retrograde signalling phenotype.
Overexpression of chloroplast-targeted ferrochelatase 1 results in a genomes uncoupled chloroplast-to-nucleus retrograde signalling phenotype.
复制标题
叶绿体靶向亚铁螯合酶 1 的过度表达会导致基因组解偶联叶绿体与细胞核的逆行信号传导表型。
DOI：
10.1098/rstb.2019.0401
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Page MT
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文献类型：
--
作者：
Page MT
叶绿体的发育需要祖质体和细胞核之间的通讯，而细胞核是编码叶绿体蛋白质的基因的所在地。从叶绿体到细胞核的逆行信号控制许多这些基因的表达，但信号通路知之甚少。四吡咯已经强烈地暗示为该信号的介质，目前的假设是由铁螯合酶1（FC 1）的活性产生的血红素是促进核基因表达所需的。我们已经通过过表达FC1并将其特异性靶向叶绿体或线粒体（该酶的两个可能位置）来验证这一假设。我们的研究结果表明，FC1靶向叶绿体的结果增加了核编码的叶绿体基因GUN 4，CA 1，HEMA 1，LHCB 2.1，CHLH的表达与氟草酮（NF）处理后，这种增加与FC1基因的表达和血红素生产的原叶绿素合成的反馈抑制测量。靶向FC1线粒体没有提高NF处理后的核编码的叶绿体基因的表达。FC 1的过表达也增加了核基因的表达，在NF处理的情况下，表明该途径是可操作的，在没有压力处理。因此，我们的研究结果支持这一假设，血红素合成是一个促进叶绿体到细胞核逆行信号。然而，并不是所有的FC1过表达线增强核基因的表达，这表明仍然有很多我们不了解FC1在这个信号通路中的作用。
Chloroplast development requires communication between the progenitor plastids and the nucleus, where most of the genes encoding chloroplast proteins reside. Retrograde signals from the chloroplast to the nucleus control the expression of many of these genes, but the signalling pathway is poorly understood. Tetrapyrroles have been strongly implicated as mediators of this signal with the current hypothesis being that haem produced by the activity of ferrochelatase 1 (FC1) is required to promote nuclear gene expression. We have tested this hypothesis by overexpressing FC1 and specifically targeting it to either chloroplasts or mitochondria, two possible locations for this enzyme. Our results show that targeting of FC1 to chloroplasts results in increased expression of the nuclear-encoded chloroplast genesGUN4,CA1,HEMA1,LHCB2.1, CHLHafter treatment with Norflurazon (NF) and that this increase correlates toFC1gene expression and haem production measured by feedback inhibition of protochlorophyllide synthesis. Targeting FC1 to mitochondria did not enhance the expression of nuclear-encoded chloroplast genes after NF treatment. The overexpression of FC1 also increased nuclear gene expression in the absence of NF treatment, demonstrating that this pathway is operational in the absence of a stress treatment. Our results therefore support the hypothesis that haem synthesis is a promotive chloroplast-to-nucleus retrograde signal. However, not all FC1 overexpression lines enhanced nuclear gene expression, suggesting there is still a lot we do not understand about the role of FC1 in this signalling pathway.This article is part of the theme issue ‘Retrograde signalling from endosymbiotic organelles’.