大脑表达 miRNA 在大脑进化中的作用及其遗传机制初步研究

人类区别于其它动物的最本质特征是其拥有其他动物所无法比拟的大脑容量及高 级的认知能力。即使与其近亲－非人灵长类相比，人也拥有比非人灵长类大好几倍的脑 容量和更为发达的认知能力。现在一般认为，人类大脑的形成是适应性选择(达尔文正 选择)的结果。但是到目前为止，对人类起源过程中大脑容量增大及认知能力提高的遗 传学机制却知之甚少。以前的研究表明，几个与大脑发育相关的蛋白质编码基因在人类 起源中受到了正向选择。同时，也有证据表明人类大脑的进化也可能是基因表达调控变 化的结果。因此寻找人与非人灵长类大脑表达基因的调控差异或许能够进一步为人与非 人灵长类为何有如此巨大的差异提供分子生物学水平上的解释。 MicroRNA(miRNA)是一类在转录后水平调控基因表达的不编码蛋白质的小 RNA(长度20－24个碱基)。通过调控靶基因的表达，miRNA参与了众多的生理过程。而 很多大脑表达的miRNA的表达量在大脑发育过程中呈显著的变化，这表明miRNA参与 了大脑的发育调控。由此可知，miRNA对其靶基因调控效率的改变很可能引起大脑发育 调控的改变。 本文通过寻找大脑表达的保守microRNA 及对其靶基因的预测，同时用比较基因组 学的方法发现：有很多microRNA 的靶基因3’UTR 的靶位点中存在人类特异突变位点。 我们推测这些人类特异突变位点可能改变microRNA 对其靶基因的表达调控效应，而调 控效应的改变可能在进化过程中对认知能力的提高发挥重要作用。利用体外报告基因系 统，我们发现有几个预测的靶基因是对应miRNA 的真实靶基因。其中，miR-127 的靶 基因（SEMA3F）3’UTR 的靶位点中所含的一个人类特有的突变增强了miR-127 对 SEMA3F 的调控效率。将该位点突变回复为黑猩猩的位点使得miR-127 对SEMA3F 的 调控效率降低到黑猩猩的水平。这表明miR-127 对SEMA3F 的调控效率的改变确实是 由该人类特异突变位点引起的。我们提供了人类特异突变位点能够引起miR-127 对SEMA3F 的调控效率的改变的体外证据，但是体内的调控模式是否如此尚需进一步的工 作。 总之，本文通过体外试验表明，miRNA靶基因3’UTR的序列变异具有功能效应，它 有可能是人类中枢神经系统在起源和演化中发挥关键作用的重要遗传机制之一。

Thermally Stable Guest-Host Polyetherketone Poled Polymer for Electro-Optical Applications

The high glass transition temperature polymer polyetherketone doped with disperse red 13 (DR13/PEK-c) has been prepared by the spin-coating method. Through in situ second-harmonic generation, the corona poling temperature was optimized by measuring the temperature dependence of the in situ second-harmonic generation signal intensity under the poling electric field. The linear electro-optic coefficients of the poled polymer films have been determined at 632.8 nm by using a simple interferometric technique. The polymer system was measured after 13 000 h, and found that it remained at 80% of its initial value.

Synthesis and Properties of Carbazole Main Chain Copolymers with Oxadiazole Pendant toward Bipolar Polymer Host: Tuning the HOMO/LUMO Level and Triplet Energy

Three new carbazole copolymers, poly(9-(2,5-diarene-[1,3,4]oxadiazole)-carbazole-alt-9-(2-ethylhexyl)-carbazole-3,6-diyl)s (P1), poly(9-(2,5-diarene-[1,3,4]oxadiazole)-2, 7-carbazole-alt-9-(2-ethylhexyl)-3, 6-carbazole-diyl)s (P2), and poly(9-(2,5-diarene-[1,3,4]oxadiazole)-carbazole-alt-9-(2-ethylhexyl)-carbazole-2,7-diyl)s (P3), were synthesized by the Suzuki coupling reaction

Solution-processable highly efficient yellow- and red-emitting phosphorescent organic light emitting devices from a small molecule bipolar host and iridium complexes

A bipolar transport compound, 2,5-bis(4-(9-(2-ethylhexyl)-9H-carbazol-3-yl) phenyl)-1,3,4-oxadiazole (CzOXD), incorporating both electron-and hole-transport functionalities, was synthesized and fully characterized by H-1 NMR, C-13 NMR, elemental analysis and mass spectrometry. Its thermal, electrochemical, electronic absorption and photoluminescent properties were studied

Solution-Processible Red Iridium Dendrimers based on Oligocarbazole Host Dendrons: Synthesis, Properties, and their Applications in Organic Light-Emitting Diodes

A series of novel red-emitting iridium dendrimers functionalized with oligocarbazole host dendrons up to the third generation (red-G3) have been synthesized by a convergent method, and their photophysical, electrochemical, and electroluminescent properties have been investigated. In addition to controlling the intermolecular interactions, oligocarbazole-based dendrons could also participate in the electrochemical and charge-transporting process. As a result, highly efficient electrophosphorescent devices can be fabricated by spin-coating from chlorobenzene solution in different device configurations.

Blue electroluminescent polymers with dopant-host systems and molecular dispersion features: polyfluorene as the deep blue host and 1,8-naphthalimide derivative units as the light blue dopants

We developed a series of highly efficient blue electroluminescent polymers with dopant-host systems and molecular dispersion features by selecting 1,8-naphthalimide derivatives as the light blue emissive dopant units, choosing polyfluorene as the deep blue emissive polymer host and covalently attaching the dopant units to the side chain of the polymer host. The polymers' EL spectra exhibited both deep blue emission from the polymer host and light blue emission from the dopant units because of the energy transfer and charge trapping from the polymer host to the dopant units.

Highly efficient red electroluminescent polymers with dopant/host system and molecular dispersion feature: polyfluorene as the host and 2,1,3-benzothiadiazole derivatives as the red dopant

By selecting polyfluorene as the polymer host, choosing 2,1,3-benzothiadiazole derivative moieties as the red dopant units and covalently attaching 0.3 mol% of the dopant units to the side chain of the polymer host, we developed a novel series of red electroluminescent polymers of dopant/host system with molecular dispersion feature. Their EL spectra exhibited predominant red emission from the dopant units because of the energy transfer and charge trapping from the polymer backbone to the dopant units. The emission wavelength of the polymers could be tuned by modifying the chemical structures of the dopant units.

Enhanced amplified spontaneous emission by assistant Forster energy transfer in DCJTB-C545T-Alq(3) coguest-host system

Amplified spontaneous emission (ASE) characteristics of a red fluorescent dye 4-(dicyanomethylene)-2-t-butyl-6(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB) were significantly improved by assistant Forster energy transfer. The coguest-host system was composed of an electron transport organic molecule tris(8-hydroxyquinoline) aluminum (Alq(3)) as host and a green fluorescent dye (10-(2-benzothiazolyl)-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H,11H-[1]benzopyrano[6,7,8-ij]quinolizin-11-one) (C545T) as assistant dopant codoped with the guest red dye DCJTB as emitter in a matrix of polystyrene (PS).

CuIn(WO4)(2) nanospindles and nanorods: controlled synthesis and host for lanthanide near-infrared luminescence properties

CuIn(WO4)(2) porous nanospindles and nanorods were synthesized through a low-cost hydrothermal method without introducing any template or surfactants. An interesting formation mechanism, namely "oriented attachment", was observed for the growth of nanorods based on the experimental process and the anisotropic intrinsic crystalline structure of CuIn(WO4)(2), which is uncommon in such a system. The near-infrared luminescence of lanthanide ions (Er, Nd, Yb and Ho) doped CuIn(WO4)(2) nanostructures, especially in the 1300-1600 nm region, was discussed and of particular interest for telecommunications applications. X-Ray diffraction, scanning electron microscopy, transmission electron microscopy, electron diffraction and photoluminescence spectra were used to characterize these materials.

Multifunctional bipolar triphenylamine/oxadiazole derivatives: highly efficient blue fluorescence, red phosphorescence host and two-color based white OLEDs

Two simple triphenylamine/oxadiazole derivatives were synthesized and fully characterized; their multifunctionality as highly efficient non-doped blue fluorescence, excellent red phosphorescent host and single-doped two-color based white OLEDs has been demonstrated.