Objective To investigate whether genes required for synaptogenesis and synaptic function are also involved in fat storage control in Caenorhabditis elegans. Methods Fat storage was examined in mutants of genes affecti...Objective To investigate whether genes required for synaptogenesis and synaptic function are also involved in fat storage control in Caenorhabditis elegans. Methods Fat storage was examined in mutants of genes affecting the synaptogenesis and synaptic function. In addition, the genetic interactions of SNAREs syntaxin/unc-64 and SNAP-25/ric-4 with daf-2, daf-7, nhr-49, sbp-1 and mdt-15 in regulating fat storage were further investigated. The tissue-specific activities of unc-64 and ric-4 were investigated to study the roles of unc-64 and ric-4 in regulating fat storage in the nervous system and/or the intestine. Results Mutations of genes required for the formation of presynaptic neurotransmission site did not obviously influence fat storage. However, among the genes required for synaptic function, the plasma membrane-associated SNAREs syntaxin/unc-64 and SNAP-25/ric-4 genes were involved in the fat storage control. Fat storage in the intestinal cells was dramatically increased in unc-64 and ric-4 mutants as revealed by Sudan Black and Nile Red strainings, although the fat droplet size was not significantly changed. Moreover, in both the nervous system and the intestine, expression of unc-64 significantly inhibited the increase in fat storage observed in unc-64 mutant. And expression of ric-4 in the nervous system completely restored fat storage in ric-4 mutant. Genetic interaction assay further indicated that both unc-64 and ric-4 regulated fat storage independently of daf-2 [encoding an insulin-like growth factor-I （IGF-I） receptor], daf-7 [encoding a transforming growth factor-β （TGF-β） ligand], and nhr-49 （encoding a nuclear hormone receptor）. Besides, mutation of daf-16 did not obviously affect the phenotype of increased fat storage in unc-64 or ric-4 mutant. Furthermore, unc-64 and ric-4 regulated fat storage probably through the ARC105/mdt-15- and SREBP/sbp-1-mediated signaling pathways. In addition, fat storage in unc-64; ric-4 was higher than that in either unc-64 or ric-4 single mutant nematodes, suggesting that unc-64 functions in parallel with ric-4 in regulating fat storage. Conclusion The plasma membrane-associated SNAREs syntaxin/ unc-64 and SNAP-25/ric-4 function in parallel in regulating fat storage in C. elegans, probably through the ARC105/mdt-15- and SREBP/sbp-1-mediated signaling pathways.展开更多
细胞极性建立和形态建成是植物组织器官发育的关键。根毛、花粉管和子叶铺板细胞已成为研究细胞极性建立以及细胞形态建成的模式系统。植物器官中,细胞形态的形成依赖分子开关传递环境或发育信号。植物中特有的一类小G蛋白(rho of plant...细胞极性建立和形态建成是植物组织器官发育的关键。根毛、花粉管和子叶铺板细胞已成为研究细胞极性建立以及细胞形态建成的模式系统。植物器官中,细胞形态的形成依赖分子开关传递环境或发育信号。植物中特有的一类小G蛋白(rho of plant,ROP)在许多细胞过程中起着信号转导的作用,ROP interactive CRIB-containing proteins(RIC)蛋白家族作为ROP下游的效应蛋白,是植物中特有的蛋白家族,参与ROP介导的复杂的信号网络。目前对RIC的研究主要集中在拟南芥中。本研究通过生物信息学方法对RIC蛋白进行α-螺旋、β-折叠、延伸链、无规则卷曲比例和亚细胞定位进行分析,并总结了RIC在根毛、花粉管和子叶铺板细胞形态建成以及植物适应逆境胁迫中所起的作用。本研究是对RIC蛋白家族系统的总结,将为进一步研究RIC的生物学功能网络提供理论参考。展开更多
基金supported by the grants from the National Natural Science Foundation of China(No. 30771113, 30870810)the Program for New Century Excellent Talents in University
文摘Objective To investigate whether genes required for synaptogenesis and synaptic function are also involved in fat storage control in Caenorhabditis elegans. Methods Fat storage was examined in mutants of genes affecting the synaptogenesis and synaptic function. In addition, the genetic interactions of SNAREs syntaxin/unc-64 and SNAP-25/ric-4 with daf-2, daf-7, nhr-49, sbp-1 and mdt-15 in regulating fat storage were further investigated. The tissue-specific activities of unc-64 and ric-4 were investigated to study the roles of unc-64 and ric-4 in regulating fat storage in the nervous system and/or the intestine. Results Mutations of genes required for the formation of presynaptic neurotransmission site did not obviously influence fat storage. However, among the genes required for synaptic function, the plasma membrane-associated SNAREs syntaxin/unc-64 and SNAP-25/ric-4 genes were involved in the fat storage control. Fat storage in the intestinal cells was dramatically increased in unc-64 and ric-4 mutants as revealed by Sudan Black and Nile Red strainings, although the fat droplet size was not significantly changed. Moreover, in both the nervous system and the intestine, expression of unc-64 significantly inhibited the increase in fat storage observed in unc-64 mutant. And expression of ric-4 in the nervous system completely restored fat storage in ric-4 mutant. Genetic interaction assay further indicated that both unc-64 and ric-4 regulated fat storage independently of daf-2 [encoding an insulin-like growth factor-I （IGF-I） receptor], daf-7 [encoding a transforming growth factor-β （TGF-β） ligand], and nhr-49 （encoding a nuclear hormone receptor）. Besides, mutation of daf-16 did not obviously affect the phenotype of increased fat storage in unc-64 or ric-4 mutant. Furthermore, unc-64 and ric-4 regulated fat storage probably through the ARC105/mdt-15- and SREBP/sbp-1-mediated signaling pathways. In addition, fat storage in unc-64; ric-4 was higher than that in either unc-64 or ric-4 single mutant nematodes, suggesting that unc-64 functions in parallel with ric-4 in regulating fat storage. Conclusion The plasma membrane-associated SNAREs syntaxin/ unc-64 and SNAP-25/ric-4 function in parallel in regulating fat storage in C. elegans, probably through the ARC105/mdt-15- and SREBP/sbp-1-mediated signaling pathways.
