2016 Vol. 7, No. 11

Prof. Huan-Yong Chen: a leading botanist and taxonomist, one of the pioneers and founders of modern plant taxonomy in China
Rui-Lan Huang
2016, 7(11): 773-776. doi: 10.1007/s13238-016-0311-4
DNA sensor cGAS-mediated immune recognition
Pengyan Xia, Shuo Wang, Pu Gao, Guangxia Gao, Zusen Fan
2016, 7(11): 777-791. doi: 10.1007/s13238-016-0320-3
The host takes use of pattern recognition receptors (PRRs) to defend against pathogen invasion or cellular damage. Among microorganism-associated molecular patterns detected by host PRRs, nucleic acids derived from bacteria or viruses are tightly supervised, providing a fundamental mechanism of host defense. Pathogenic DNAs are supposed to be detected by DNA sensors that induce the activation of NFκB or TBK1-IRF3 pathway. DNA sensor cGAS is widely expressed in innate immune cells and is a key sensor of invading DNAs in several cell types. cGAS binds to DNA, followed by a conformational change that allows the synthesis of cyclic guanosine monophosphate-adenosine monophosphate (cGAMP) from adenosine triphosphate and guanosine triphosphate. cGAMP is a strong activator of STING that can activate IRF3 and subsequent type I interferon production. Here we describe recent progresses in DNA sensors especially cGAS in the innate immune responses against pathogenic DNAs.
Research articles
Structural studies on MRG701 chromodomain reveal a novel dimerization interface of MRG proteins in green plants
Yanchao Liu, Hong Wu, Yu Yu, Ying Huang
2016, 7(11): 792-803. doi: 10.1007/s13238-016-0310-5
MRG proteins are conserved during evolution in fungi, flies, mammals and plants, and they can exhibit diversified functions. The animal MRGs were found to form various complexes to activate gene expression. Plant MRG1/2 and MRG702 were reported to be involved in the regulation of flowering time via binding to H3K36me3-marked flowering genes. Herein, we determined the crystal structure of MRG701 chromodomain (MRG701CD). MRG701CD forms a novel dimerization fold both in crystal and in solution. Moreover, we found that the dimerization of MRG chromodomains is conserved in green plants. Our findings may provide new insights into the mechanism of MRGs in regulation of gene expression in green plants.
A new method for quantifying mitochondrial axonal transport
Mengmeng Chen, Yang Li, Mengxue Yang, Xiaoping Chen, Yemeng Chen, Fan Yang, Sheng Lu, Shengyu Yao, Timothy Zhou, Jianghong Liu, Li Zhu, Sidan Du, Jane Y. Wu
2016, 7(11): 804-819. doi: 10.1007/s13238-016-0268-3
Axonal transport of mitochondria is critical for neuronal survival and function. Automatically quantifying and analyzing mitochondrial movement in a large quantity remain challenging. Here, we report an efficient method for imaging and quantifying axonal mitochondrial transport using microfluidic-chamber-cultured neurons together with a newly developed analysis package named "MitoQuant". This tool-kit consists of an automated program for tracking mitochondrial movement inside live neuronal axons and a transient-velocity analysis program for analyzing dynamic movement patterns of mitochondria. Using this method, we examined axonal mitochondrial movement both in cultured mammalian neurons and in motor neuron axons of Drosophila in vivo. In 3 different paradigms (temperature changes, drug treatment and genetic manipulation) that affect mitochondria, we have shown that this new method is highly efficient and sensitive for detecting changes in mitochondrial movement. The method significantly enhanced our ability to quantitatively analyze axonal mitochondrial movement and allowed us to detect dynamic changes in axonal mitochondrial transport that were not detected by traditional kymographic analyses.
Role of circadian gene Clock during differentiation of mouse pluripotent stem cells
Chao Lu, Yang Yang, Ran Zhao, Bingxuan Hua, Chen Xu, Zuoqin Yan, Ning Sun, Ruizhe Qian
2016, 7(11): 820-832. doi: 10.1007/s13238-016-0319-9
Biological rhythms controlled by the circadian Clock are absent in embryonic stem cells (ESCs). However, they start to develop during the differentiation of pluripotent ESCs to downstream cells. Conversely, biological rhythms in adult somatic cells disappear when they are reprogrammed into induced pluripotent stem cells (iPSCs). These studies indicated that the development of biological rhythms in ESCs might be closely associated with the maintenance and differentiation of ESCs. The core circadian gene Clock is essential for regulation of biological rhythms. Its role in the development of biological rhythms of ESCs is totally unknown. Here, we used CRISPR/CAS9-mediated genetic editing techniques, to completely knock out the Clock expression in mouse ESCs. By AP, teratoma formation, quantitative real-time PCR and Immunofluorescent staining, we did not find any difference between Clock knockout mESCs and wild type mESCs in morphology and pluripotent capability under the pluripotent state. In brief, these data indicated Clock did not influence the maintaining of pluripotent state. However, they exhibited decreased proliferation and increased apoptosis. Furthermore, the biological rhythms failed to develop in Clock knockout mESCs after spontaneous differentiation, which indicated that there was no compensational factor in most peripheral tissues as described in mice models before (DeBruyne et al., 2007b). After spontaneous differentiation, loss of Clock protein due to Clock gene silencing induced spontaneous differentiation of mESCs, indicating an exit from the pluripotent state, or its differentiating ability. Our findings indicate that the core circadian gene Clock may be essential during normal mESCs differentiation by regulating mESCs proliferation, apoptosis and activity.
The role of endosomal cholesterol trafficking protein, StAR-related lipid transfer domain 3 (StarD3/MLN64), in BRIN-BD11 insulinoma cells
Joana Borges Pinto, Annette Graham
2016, 7(11): 833-838. doi: 10.1007/s13238-016-0315-0
3-Anhydro-6-hydroxy-ophiobolin A displays high in vitro and in vivo efficacy against influenza A virus infection
Song Wang, Xiaoqin Luo, Ruoxiang Yan, Quanxin Wang, Qiuyue Qi, Xiaojuan Chi, Lanlan Zhang, Ziding Yu, Binxiang Cai, Ji-Long Chen, Hongwei Liu
2016, 7(11): 839-843. doi: 10.1007/s13238-016-0325-y
Three dimensional collagen scaffolds promote iPSC induction with higher pluripotency
Qi Gu, He Zhu, Lei Chen, Ling Shuai, Jinhui Fang, Jun Wu, Lei Liu, Wei Li, Jianwu Dai, Jie Hao, Qi Zhou
2016, 7(11): 844-848. doi: 10.1007/s13238-016-0321-2