Regulatory BC1 RNA and the fragile X mental retardation protein: convergent functionality in brain

Background

BC RNAs and the fragile X mental retardation protein (FMRP) are translational repressors that have been implicated in the control of local protein synthesis at the synapse. Work with BC1 and Fmr1 animal models has revealed that phenotypical consequences resulting from the absence of either BC1 RNA or FMRP are remarkably similar. To establish functional interactions between BC1 RNA and FMRP is important for our understanding of how local protein synthesis regulates neuronal excitability.

Methodology/Principal Findings

We generated BC1−/− Fmr1−/− double knockout (dKO) mice. We examined such animals, lacking both BC1 RNA and FMRP, in comparison with single knockout (sKO) animals lacking either one repressor. Analysis of neural phenotypical output revealed that at least three attributes of brain functionality are subject to control by both BC1 RNA and FMRP: neuronal network excitability, epileptogenesis, and place learning. The severity of CA3 pyramidal cell hyperexcitability was significantly higher in BC1−/− Fmr1−/− dKO preparations than in the respective sKO preparations, as was seizure susceptibility of BC1−/− Fmr1−/− dKO animals in response to auditory stimulation. In place learning, BC1−/− Fmr1−/− dKO animals were severely impaired, in contrast to BC1−/− or Fmr1−/− sKO animals which exhibited only mild deficits.

Conclusions/Significance

Our data indicate that BC1 RNA and FMRP operate in sequential-independent fashion. They suggest that the molecular interplay between two translational repressors directly impacts brain functionality.     

猫嗅球外丛层和僧帽细胞层年龄相关形态学变化

分别用Nissl法及免疫组织化学ABC法标记青、老年猫嗅球中嗅觉二级神经元和外丛层胶质细胞,显微镜下观察其分布并计数,对嗅觉二级神经元胞体直径和外丛层厚度进行测量,比较其年龄相关性变化,研究神经元与胶质细胞之间的关系,探讨老年性嗅觉功能衰退的相关神经机理。结果显示,老年猫嗅觉二级神经元胞体直径和分布密度均有不同程度的显著性下降(P<0.05);外丛层厚度变化不明显(P>0.05);外丛层胶质细胞特别是星形胶质细胞显著性增生(P<0.05)。表明在衰老过程中嗅觉二级神经元有丢失,并呈现功能下降,可能是老年性嗅觉功能衰退的原因之一。同时外丛层胶质细胞增生以进一步保护神经元,延缓其衰老。     

Molecular Evolution of the Primate Antiviral Restriction Factor Tetherin

Background

Tetherin is a recently identified antiviral restriction factor that restricts HIV-1 particle release in the absence of the HIV-1 viral protein U (Vpu). It is reminiscent of APOBEC3G and TRIM5a that also antagonize HIV. APOBEC3G and TRIM5a have been demonstrated to evolve under pervasive positive selection throughout primate evolution, supporting the red-queen hypothesis. Therefore, one naturally presumes that Tetherin also evolves under pervasive positive selection throughout primate evolution and supports the red-queen hypothesis. Here, we performed a detailed evolutionary analysis to address this presumption.

Methodology/Principal Findings

Results of non-synonymous and synonymous substitution rates reveal that Tetherin as a whole experiences neutral evolution rather than pervasive positive selection throughout primate evolution, as well as in non-primate mammal evolution. Sliding-window analyses show that the regions of the primate Tetherin that interact with viral proteins are under positive selection or relaxed purifying selection. In particular, the sites identified under positive selection generally focus on these regions, indicating that the main selective pressure acting on the primate Tetherin comes from virus infection. The branch-site model detected positive selection acting on the ancestral branch of the New World Monkey lineage, suggesting an episodic adaptive evolution. The positive selection was also found in duplicated Tetherins in ruminants. Moreover, there is no bias in the alterations of amino acids in the evolution of the primate Tetherin, implying that the primate Tetherin may retain broad spectrum of antiviral activity by maintaining structure stability.

Conclusions/Significance

These results conclude that the molecular evolution of Tetherin may be attributed to the host–virus arms race, supporting the Red Queen hypothesis, and Tetherin may be in an intermediate stage in transition from neutral to pervasive adaptive evolution.     

暴发脑膜脑炎流行的新型毒株的全基因序列

吉林省延边地区１９９６年６月发生无菌性脑膜脑炎流行,从病人脑脊液和粪便标本中分离到多株病毒,血清学实验证明所分离的病毒为此次无菌性脑膜脑炎流行的病因。对其中的２株病毒（Ｙａｎｂｉａｎ９６－８３ｃｓｆ和Ｙａｎｂｉａｎ９６－８５ｃｓｆ）测定了全基因核酸序列并帮了比较分析。结果所测２株病毒核酸长度均为７４５６ｂｐ〔包括３端ｐｏｌｙ（Ａ）尾〕,两者间仅有１３个位点不同,同源性达９９．８％,在进化树上位于同     

三种不同方法固定的石蜡切片中RNA的分析

研究在 10 %中性福尔马林、丙酮、甲醇 氯仿 冰醋酸 3种方法固定的石蜡切片中提取RNA的质量和数量 .取 2 5 0g体重的Wistar大鼠的肾脏 ,分别采用 10 %中性福尔马林、丙酮、甲醇 氯仿 冰醋酸 3种方法固定 ,石蜡包埋 ,H E染色 ;采用RNA裂解液、TRIZOL试剂 2种方法提取切片RNA ,逆转录为cDNA ,采用普通PCR和SYBRGREEN 1定量PCR分析RNA质量和数量 .结果表明 ,3种固定方法都可保持组织良好的结构和形态 ;采用 2种提取方法 ,均可经RT PCR扩增出 180bp大鼠磷酸甘油醛脱氢酶 (G3PDH)、5 6 5bpβ肌动蛋白 (β actin)、10 0bp纤溶酶系活化剂抑制物 1(PAI 1) ;但采用RNA裂解液时 ,比TRIZOL试剂可提取更多的RNA .     

One-step knockin for inducible expression in mouse embryonic stem cells

Transgenesis enables the elucidation of gene function; however, constant transgene expression is not always desired. The tetracycline responsive system was devised to turn on and off transgene expression at will. It has two components: a doxycycline (dox)-controlled transactivator (TA) and an inducible expression cassette. Integration of these transgenes requires two transfection steps usually accomplished by sequential random integration. Unfortunately, random integration can be problematic due to chromatin position effects, integration of variable transgene units, and mutation at the integration site. Therefore, targeted transgenesis and knockin were developed to target the TA and the inducible expression cassette to a specific location, but these approaches can be costly in time, labor, and money. Here, we describe a one-step Cre-mediated knockin system in mouse embryonic stem cells that positions the TA and inducible expression cassette to a single location. Using this system, we show dox-dependent regulation of eGFP at the DNA topoisomerase 3β promoter. Because Cre-mediated recombination is used in lieu of gene targeting, this system is fast and efficient.     

老年冠心病患者服用抗血小板药物的依从性分析及护理对策

目的:分析老年冠心痛患者服用抗血小板药物的依从性,寻求护理干预的有效途径.方法:自行设计服用抗血小板药物依从性调查表,通过调查与健康教育相结合的方式,对128例年龄在68～95岁的老年冠心病患者服药依从性问题进行调查分析.结果:通过临床医师知道抗血小板药物作用的占100%;知道终身服用抗血小板药物意义的占35%;服用抗血小板药物遇到问题而自行停药的占0%;健康教育后能坚持终身服用抗血小板药物的占95%.结论:相对于老年冠心痛患者,有效的健康教育能极大地提高患者服药依从性.临床医护人员对患者进行健康教育的同时,对家属的教育也很重要.通过健康教育干预,使其掌握药物的基本知识,告知获益大于风险,启动家庭支持系统,可显著提高老年冠心病患者服用抗血小板药物依从性.