He Shan, Sun Yan, Yang Qian, Zhang Xiangyu, Huang Qingpei, Zhao Peng, Sun Mengxiang, Liu Jingjing, Qian Weiqiang, Qin Genji, Gu Hongya, Qu Li-Jia
State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, School of Life Sciences, Peking University, Beijing, China.
Department of Cell and Development Biology, College of Life Science, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan, China.
PLoS Genet. 2017 Jan 17;13(1):e1006553. doi: 10.1371/journal.pgen.1006553. eCollection 2017 Jan.
Imprinted genes display biased expression of paternal and maternal alleles and are only found in mammals and flowering plants. Compared to several hundred imprinted genes that are functionally characterized in mammals, very few imprinted genes were confirmed in plants and even fewer of them have been functionally investigated. Here, we report a new imprinted gene, NUWA, in plants. NUWA is an essential gene, because loss of its function resulted in reduced transmission through the female gametophyte and defective cell/nuclear proliferation in early Arabidopsis embryo and endosperm. NUWA is a maternally expressed imprinted gene, as only the maternal allele of NUWA is transcribed and translated from gametogenesis to the 16-cell globular embryo stage after fertilization, and the de novo transcription of the maternal allele of NUWA starts from the zygote stage. Different from other identified plant imprinted genes whose encoded proteins are mostly localized to the nucleus, the NUWA protein was localized to the mitochondria and was essential for mitochondria function. Our work uncovers a novel imprinted gene of a previously unidentified type, namely, a maternal-specific expressed nuclear gene with its encoded protein localizing to and controlling the function of the maternally inherited mitochondria. This reveals a unique mechanism of maternal control of the mitochondria and adds an extra layer of complexity to the regulation of nucleus-organelle coordination during early plant development.
印记基因表现出父本和母本等位基因的偏向性表达，且仅在哺乳动物和开花植物中发现。与数百个在哺乳动物中具有功能特征的印记基因相比，植物中已确认的印记基因很少，对其进行功能研究的更少。在此，我们报道了植物中的一个新的印记基因NUWA。NUWA是一个必需基因，因为其功能丧失导致通过雌配子体的传递减少，以及拟南芥早期胚胎和胚乳中的细胞/核增殖缺陷。NUWA是一个母本表达的印记基因，因为从配子发生到受精后16细胞球形胚阶段，只有NUWA的母本等位基因被转录和翻译，并且NUWA母本等位基因的从头转录从合子阶段开始。与其他已鉴定的植物印记基因不同，其编码蛋白大多定位于细胞核，而NUWA蛋白定位于线粒体，并且对线粒体功能至关重要。我们的工作揭示了一种以前未鉴定类型的新的印记基因，即一种母本特异性表达的核基因，其编码蛋白定位于并控制母本遗传的线粒体的功能。这揭示了母本控制线粒体的独特机制，并为植物早期发育过程中核-细胞器协调的调控增加了一层额外的复杂性。
