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Ash2l-1/Ash2l-2在小鼠胚胎干细胞中的表达特异性及互补效应 被引量:1
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作者 谢晶 范辰 +2 位作者 张景龙 张仕强 谷峰 《遗传》 CAS CSCD 北大核心 2018年第3期237-249,共13页
H3K4me3是一种重要的表观遗传修饰,主要由MLL(mixed lineage leukemia)甲基转移酶复合体催化,对小鼠胚胎干细胞(mouse embryonic stem cells,m ESCs)自我更新能力的维持具有重要作用。ASH2L是MLL复合体中一个重要的核心亚单位,参与调控m... H3K4me3是一种重要的表观遗传修饰,主要由MLL(mixed lineage leukemia)甲基转移酶复合体催化,对小鼠胚胎干细胞(mouse embryonic stem cells,m ESCs)自我更新能力的维持具有重要作用。ASH2L是MLL复合体中一个重要的核心亚单位,参与调控m ESCs中染色质的开放状态。ASH2L在m ESCs中有2个异构体:ASH2L-1(80 k Da)和ASH2L-2(65 k Da),且以ASH2L-2的表达为主;而在小鼠胚胎成纤维细胞(mouse embryonic fibroblast,MEF)中,只有ASH2L-1表达。目前,Ash2l-1和Ash2l-2在m ESCs中的作用尚不清楚。本文利用CRISPR/Cas9基因组编辑技术,建立了Ash2l-1^(–/–)和Ash2l-2^(–/–)m ESCs。通过碱性磷酸酶染色、免疫荧光染色和q RT-PCR发现,Ash2l-1^(–/–)和Ash2l-2^(–/–)m ESCs在碱性磷酸酶、多能性调控转录因子(Oct4、Nanog、Sox2和Klf4)的表达与野生型对照无显著差异。通过拟胚体分化实验,发现Ash2l-1^(–/–)m ESCs诱导的拟胚体在Snai2(外胚层标记基因)和Gata4(内胚层标记基因)的表达上显著低于野生型m ESCs诱导的拟胚体(P<0.01)。通过Western blotting,发现Ash2l-1^(–/–)m ESCs中ASH2L-2的表达显著上调(P<0.01),Ash2l-2^(–/–)m ESCs中ASH2L-1的表达显著上调(P<0.01),而Ash2l-1^(–/–)和Ash2l-2^(–/–)m ESCs中,基因组H3K4me3的表达与野生型对照并无显著差异。这表明Ash2l-1和Ash2l-2之间存在补偿效应。利用JASPAR和KEGG预测分析发现,Ash2l-1和Ash2l-2启动子区分别具有3个和16个潜在的多能性转录因子结合位点,这些转录因子可能介导实现Ash2l-1和Ash2l-2之间的补偿效应。以上结果表明,Ash2l-1和Ash2l-2之间的补偿效应可能参与m ESCs多能性的维持和基因组H3K4me3的调控。 展开更多
关键词 H3K4me3 ASH2L异构体 CRISPR/Cas9 小鼠胚胎干细胞 补偿效应
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Routing and scheduling co-design for holistic software-defined deterministic network 被引量:1
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作者 jinglong zhang Fengyuan Zhu +3 位作者 Zeming Yang Cailian Chen Xiaohua Tian Xinping Guan 《Fundamental Research》 CAS CSCD 2024年第1期25-34,共10页
As a result of the growing complexity of industrial Internet applications,traditional hardware-based network designs are encountering challenges in terms of programmability and dynamic adaptability as they struggle to... As a result of the growing complexity of industrial Internet applications,traditional hardware-based network designs are encountering challenges in terms of programmability and dynamic adaptability as they struggle to meet the real-time,high-reliability transmission requirements for the vast quantities of data generated in industrial environments.This paper proposes a holistic software-defined deterministic network(HSDDN)design solution.This solution uses a centralized controller to implement a comprehensive software definition,ranging from the network layer down to the physical layer.Within the wireless access domain,we decouple the standard radio-frequency modules from baseband processing to realize a software-defined physical layer,which then allows us to adjust the data transmission cycles and tag the trigger rates to meet demand for low-power,high-concurrency transmission.Within the wired network domain,we integrate software-defined networking with time-sensitive networking and propose a coordinated design strategy to address routing and the deterministic scheduling problem.We define a set of constraints to ensure collaborative transmission of the periodic and aperiodic data flows.To guarantee load balancing across all paths and timeslots,we introduce the Jain’s fairness index as the optimization objective and then construct a nondeterministic polynomial-time(NP)-hard joint optimization problem.Furthermore,an algorithm called Tabu search for routing and scheduling with dual-stages(TSRS-DS)is proposed.Simulation experiments demonstrate the effectiveness of the proposed HSDDN architecture. 展开更多
关键词 Deterministic networking Software-defined networking Software-defined physical layer Time-sensitive networking Backscatter communication Routing and scheduling co-design
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清代海防重器——蓬莱水城道光铁炮
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作者 张景龙 《中国港口》 2017年第A02期98-104,共7页
本文以蓬莱水城保存的三门清朝道光年间的大铁炮为研究对象,结合炮身铭文内容,对照鸦片战争相关史料,佐证福建工匠参与铸造山东海防重型火炮的史实;同时通过探讨蓬莱水城道光铁炮与鸦片战争的关系,揭示了蓬莱水城清代铁炮海防功能的衰微。
关键词 蓬莱水城 铁炮 托浑布 山东海防 鸦片战争
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