多发性骨髓瘤细胞中一个新的Alu超基因家族成员的克隆与分析

根据Genebank收录的多发性骨髓瘤细胞株 (ARH 77)表达上调ESTAF4 97797设计引物 ,采用半定量RT PCR证实了多发性骨髓瘤患者及正常人骨髓细胞中该expressedsequencetags(EST)存在表达差异 .用ESTAF4 97797作探针筛选人胚肾cDNA文库 ,获得cDNA克隆经测序并用生物信息学方法对该序列进行了初步分析 .AF4 97797在多发性骨髓瘤患者骨髓中确有较高的表达 ,而在正常人骨髓细胞中低表达 .获得的全长cDNA克隆序列长 1 2 4 8bp(Genebank登录号 :AY0 94 6 1 2 ) .生物信息学分析显示该片段全长cDNA编码 4 4个氨基酸的蛋白产物且可能属于Alu家族成员 .基因AY0 94 6 1 2为一个在多发性骨髓瘤中表达上调的新基因 ,其改变可能与多发性骨髓瘤的发生与发展有关 .

超基因:基因表达的“多面手”

真核生物基因组的转录是基因表达的重要环节,转录产物不仅包括编码蛋白的信使RNA,还包括众多类型的非编码RNA。在转录过程中,有些基因位点可生成不止一种RNA分子,其中可能包括编码RNA分子,但更多的是非编码RNA分子,这类可转录生成多种RNA分子的基因位点被命名为超基因。根据转录模式的不同,超基因分为Ⅰ型、Ⅱ型和Ⅲ型。本文结合实例,对各型超基因的转录特点及其在细胞中的调控作用进行综述。

多发性骨髓瘤中新的表达上调Alu超基因家族成员在不同肿瘤组织中的表达分析

目的 :分析多发性骨髓瘤患者中表达上调基因在正常组织及不同类型实质性肿瘤组织中的表达。方法 :运用RNA点杂交、半定量RT -PCR方法分析AY0 94 6 12在肿瘤组织与正常组织中的表达差异。结果 :多组织表达膜杂交结果显示AY0 94 6 12在各种正常组织以及几种癌细胞系中均有表达。RNA点杂交及半定量RT -PCR均显示AY0 94 6 12在直肠癌、肺癌、脑瘤组织中均表达水平上调 ,其它如胃癌、肝癌、子宫内膜癌、卵巢癌患者的组织中亦有部分表达水平上调。结论 :AY0 94 6 12的表达上调可能是恶性肿瘤发生的一个重要因素。

克隆超基因家族中新基因的一种PCR同源引物

目的：用同源引物克隆ＲＮＡ低丰度表达的小鼠β－趋化因子受体。方法：将β－趋化因子受体小鼠ＭＩＰ－１αＲ，人ＭＣＰ－１Ｒ和大鼠ＩＬ－８Ｒ跨膜区中高度保守的氨基酸序列中的核苷酸进行相似序列对比后，设计出同源引物，再用ＲＴ－ＰＣＲ扩增出ＤＮＡ片段，经基因库检索为该超基因家族中的新基因序列后设计特异引物，用ＭａｒａｔｈｏｎＰＣＲ扩增出该新基因。结果：成功克隆出小鼠β－趋化因子受体５（ＣＣＲ５）ｃＤＮＡ全基因序列，序列全长２８８８ｂｐ，开放阅读框１０６５个核苷酸，编码３５５个氨基酸。该序列经序列分析、配体结合试验及国际基因库检索证实为该超基因家族中的一个新基因成员。结论：该克隆策略的引物设计思路较为新颖，能有效捕获超基因家族中的新基因。该克隆方法敏感、高效。

桃CYP450超基因家族的基因鉴定及Prupe.6G046800的功能分析

【目的】鉴定分析桃(Prunus persica)细胞色素P450(Cytochrome P450,CYP450)超基因家族成员,并对Prupe.6G046800基因进行功能分析。【方法】系统分析了桃的CYP450超基因家族功能。采用比对和检索2种方法鉴定桃基因组中的CYP450超家族成员,构建上述基因和拟南芥同源基因的系统进化树并分析其基因结构;运用转录组学数据分析该家族基因组织特异性表达和果实发育时期表达量变化;最后,构建了其中1个重要基因Prupe.6G046800的过表达载体并转化番茄,采用瞬时转化的方法分析该基因的启动子活性。【结果】桃基因组CYP450超家族成员共295个,可分为9个家族簇,其中包含4个多基因家族簇和5个单基因家族簇。未发现CYP727和CYP746家族簇成员,其中CYP71家族簇成员数量最多。组织特异性表达分析显示,CYP450超家族在桃不同组织中均有表达,有145个基因至少在1个组织中表达,以根中特异表达基因数目最多。选择上述表达基因进行基因结构分析,发现桃的CYP450s基因长度跨度大、外显子数量差异明显。分析了CYP450超基因家族在果实发育过程中的表达,发现有45个基因表达量持续下降,36个基因持续上升。将Prupe.6G046800在番茄中进行异源稳定转化,此基因在过量表达的番茄植株不同组织中表达有着显著差异,且明显高于野生型番茄。启动子顺式作用元件分析显示,该基因可能受到光、干旱及激素等信号的调控。【结论】从桃基因组中鉴定出295个CYP450超家族成员,可分为9个家族簇。转录组数据显示,CYP450s基因参与了桃的整个生长发育过程。Prupe.6G046800过表达导致番茄单果质量降低,表明Prupe.6G046800参与果实发育调控。

TRP超基因家族与疼痛

目前的研究越来越表明：痛也即伤害性刺激的感受，是始于周边终末的伤害性受体，这是一类高度特化的初级神经元。小薄髓A。纤维和无髓C纤维的轴突上有伤害性受体。这种接受特化感觉神经元由它们表达的转导高离子通道受体来决定其特性，这类受体对外界的刺激有一个高阈值，也就是说它的被激活需要被敏化。伤害性受体一旦被激活将引起离子通道的开放，导致Na＋、Ca2＋内流和K＋外流，从而导致膜的去极化。痛觉纤维的去极化最终都共同导致炎性递质的胞吐，TRP超基因家族是如何被激活引起去极化？该类受体是如何被调节敏化？其能胞吐些什么特异性递质？本文将按此一一来阐述。

植物查尔酮合成酶超基因家族的分子进化

查尔酮合成酶(CHS)超基因家族又称为植物类型III聚酮合酶超基因家族,其编码酶通过催化和合成一系列结构多样及生理活性各异的次生代谢物,在植物生长发育和适应环境的过程中扮演着重要角色。为全面了解CHS超基因家族在植物中的进化规律,重建其进化历史,该研究利用14种具有全基因组数据的代表植物,通过生物信息学手段,深入挖掘和分析了不同植物类群基因组中查尔酮合成酶超基因家族的成员构成,推测了其可能的扩增机制和功能分歧,并探讨了该超基因家族在植物中的总体进化趋势。结果共识别144条具有表达信息的同源序列,它们全部来自9种陆生植物的基因组,藻类植物基因组中没有发现相关序列。系统发育和进化分析表明,CHS超基因家族的起源古老,它们可能为适应复杂的生态环境而出现在早期的陆生植物中,之后在长期的进化过程中不断发生谱系的特异扩张和拷贝丢失,最后通过功能分歧的形式在不同植物类群中被分别固定。此外,进化检验也显示,尽管CHS超基因家族内部发生了多样的遗传改变,但整个超基因家族仍处于强烈的纯化选择之下,并且个体基因中也无任何单氨基酸位点受到正向选择的影响。

植物查尔酮合成酶超基因家族组成及分子进化

本研究共收集来自于39个不同植物物种的59个查尔酮合成酶基因(CHS)序列,采用生物信息学方法对参试的CHS序列进行基因组成及结构分析,进而通过邻接法构建CHS超基因家族系统进化树。结果显示,CHS广泛分布于不同物种,整个超基因家族序列具有较高同源性;CHS超基因家族在其进化过程中分为2个亚家族,2大亚家族之间遗传距离为0.048,其进化分异程度呈保守态势。参试的所有CHS基因在其指导蛋白合成从而实现性状表达水平较为统一。

籼稻细胞色素P450超基因家族成员及其EST证据

将预测的籼稻基因同289个已知的拟南芥细胞色素P450基因进行蛋白质序列比对,在籼稻(Oryza sativa L.ssp.indica)工作框架草图中找到了528个可能的细胞色素P450基因,初步认定上述籼稻P450基因来自于已在拟南芥中确定的40个P450基因家族.比较拟南芥和籼稻的细胞色素P450s在基因家族中的分布,发现这两种植物P450基因的家族分布规律总体相似,但也有不同,例如:CYP71,CYP72,CYP76,CYP89,CYP94,CYP709等家族的成员在籼稻中远远多于拟南芥的;CYP705家族的成员在籼稻中没有,但在拟南芥中却多达33个.另外,发现籼稻CYP71和CYP81家族的成员在基因组中成串联重复排列,它们可能是进化过程中基因复制的结果.进一步将这些籼稻P450基因的DNA序列同籼稻表达序列标签(expression sequence tags,ESTs)进行核酸序列比对,为263个可能的籼稻P450s找到了ESTs的证据,说明这些基因在转录水平上确实有所表达.

HOX基因在造血干/祖细胞中的表达以及与白血病的关系

同源盒基因（homeoboxgene）是一组含有一个长度为183bp进化高度保守的碱基（DNA）序列即同源盒的超基因家族,该序列编码一段保守性较高、由61个氨基酸残基组成的DNA结合结构域[同源结构域（Homeodommn，HD）]。同源盒基因广泛存在于线虫、果蝇、老鼠和人类等物种中，编码的蛋白质是转录因子。通过与很多转录共因子的相互作用（如PBx和Meis等）来调节转录以完成造血发生。

氧化鲨烯环化酶(OSC)基因家族研究进展

氧化鲨烯环化酶(OSC)是一个超基因家族,可催化2,3-氧化鲨烯环化生成甾醇和三萜类前体物质,是三萜类前体物质和甾醇生成的关键酶。随着现代生物技术的不断发展,越来越多的OSC基因被分离和克隆并进行功能验证以及生物信息学分析。虽然研究者们已经对OSC的研究已取得了一定的进展,但其催化的下游的反应机理尚不清楚。本文对OSC基因家族的研究现状、其所参与的生物合成代谢途径、OSC基因的结构特征和表达调控、定点突变研究和分子进化研究等进行了简要阐述。

BB星奇遇

我在空中飘着飘着,越升越高,最后竟然飞离了地球。“啊,那个蓝色的星球不正是地球吗?我离开地球了!”我十分兴奋。太空中的各种星星闪烁着耀眼的光芒。

Preparation of Superparamagnetic Dextran-coated Iron Oxide Nanoparticles used as a Novel Gene Carrier into Human Bladder Cancer Cells'

Objective: Application of magnetic nanoparticles as gene carrier in gene therapy has developed quickly. This study was designed to investigate the preparation of superparamagnetic dextran-coated iron oxide nanoparticles (SDION) and the feasibility of SDION used as a novel gene carrier for plasmid DNA in vitro. Methods: SDION were prepared by chemical coprecipitation and separated by gel filtration on Sephacryl S-300HR, characterized by TEM, laser scattering system and Vibrating Sample Magnetometer Signal Processor. The green fluorescent protein (pGFP-C2) plasmid DNA was used as target gene. SDION-pGFP-C2 conjugate compounds were produced by means of oxidoreduction reaction. The connection ratio of SDION and pGFP-C2 DNA was analyzed and evaluated by agarose electrophoresis and the concentration of pGFP-C2 in supernatant was measured. Using liposome as control, the transfection efficiency of SDION and liposome was respectively evaluated under fluorescence microscope in vitro. Results: The diameter of SDION ranges from 3 nm to 8 nm, the effective diameter was 59.2 nm and the saturation magnetization was 0.23 emu/g. After SDION were reasonably oxidized, SDION could connect with pGFP-C2 to a high degree. The transfection efficiency of SDION as gene carrier was higher than that of liposome. Conclusion: The successes in connecting SDION with pGFP-C2 plasmid by means of oxidoreduction reaction and in transferring pGFP-C2 gene into human bladder cancer BIU-87 cells in vitro provided the experimental evidence for the feasibility of SDION used as a novel gene carrier.

HFE gene in primary and secondary hepatic iron overload

Distinct from hereditary haemochromatosis, hepatic iron overload is a common finding in several chronic liver diseases. Many studies have investigated the prevalence, distribution and possible contributory role of excess hepatic iron in non-haemochromatotic chronic liver diseases. Indeed, some authors have proposed iron removal in liver diseases other than hereditary haemochromatosis. However, the pathogenesis of secondary iron overload remains unclear. The High Fe （HFE） gene has been implicated, but the reported data are controversial. In this article, we summarise current concepts regarding the cellular role of the HFE protein in iron homeostasis. We review the current status of the literature regarding the prevalence, hepatic distribution and possible therapeutic implications of iron overload in chronic hepatitis C, hepatitis B, alcoholic and non- alcoholic fatty liver diseases and porphyria cutanea tarda. We discuss the evidence regarding the role of HFE gene mutations in these liver diseases. Finally, we summarize the common and specific features of iron overload in liver diseases other than haemochromatosis.

Microbubble-enhanced ultrasound exposure improves gene transfer in vascular endothelial cells

AIM： To explore the effects of ultrasound exposure combined with microbubble contrast agent （SonoVue） on the permeability of the cellular membrane and on the expression of plasrnid DNA encoding enhanced green fluorescent protein （pEGFP） transfer into human umbilical vein endothelial cells （HUVECs）. METHODS： HUVECs with fluorescein isothiocyanatedextran （FD500） and HUVECs with pEGFP were exposed to continuous wave （1.9 MHz, 80.0 mW/cm^2） for 5 min, with or without a SonoVue. The percentage of FD500 taken by the HUVECs and the transient expression rate of pEGFP in the HUVECs were examined by fluorescence microscopy and flow cytornetry, respectively. RESULTS： The percentage of FDS00-positive HUVECs in the group of ultrasound exposure combined with SonoVue was significantly higher than that of the group of ultrasound exposure alone （24.0%± 5.5% vs 66.6% ± 4.1%, P 〈 0.001）. Compared with the group of ultrasound exposure alone, the transfection expression rate of pEGFP in HUVECs was markedly increased with the addition of SonoVue （16.1% ± 1.9% vs 1.5% ± 0.2%, P 〈 0.001）. No statistical significant difference was observed in the HUVECs survival rates between the ultrasound group with and without the addition of SonoVue （94.1% ± 2.3% vs 91.1% ± 4.1% ）. CONCLUSION： The cell membrane permeability of HUVECs and the transfection efficiency of pEGFP into HUVECs exposed to ultrasound are significantly increased after addition of an ultrasound contrast agent without obvious damage to the survival of HUVECs. This non- invasive gene transfer method may be a useful tool for clinical gene therapy of hepatic tumors.

Relationship between preoperative staging by endoscopic ultrasonography and MMP-9 expression in gastric carcinoma

AIM: To investigate the relationship between the staging by endoscopic ultrasonography (EUS) and the expression of carcinoma metastasis associated gene in the patients with gastric carcinoma. METHODS: Sixty-three patients with gastric cancer were diagnosed by electric gastroscopy and EUS. The preoperative staging of gastric cancer was measured by EUS and compared with pathologic staging and MMP-9 expression. Peripheral serum level of MMP-9 was measured with enzyme-linked immunosorbent assay (ELISA), while the expression of MMP-9 protein was tested with immunohistochemistry and hybridization in situ in the gastric carcinoma tissues. RESULTS: The total accuracy of EUS in estimating invasive depth of gastric cancer was 80.95%, while that in estimating lymphatic metastasis was 73.02%. Serum MMP-9 levels were consistent with the expression of MMP-9 protein and MMP-9 mRNA in tissue, a result closely correlated with invasive degree, staging with EUS and lymphatic metastasis in gastric cancer (P < 0.05). The total accuracy of estimating invasive depth in gastric cancer was 95.22% using both EUS and MMP-9. CONCLUSION: The MMP-9 level of preoperative serum presents the reference value for preoperative staging by EUS in the patients with gastric cancer. When serum MMP-9 level in gastric cancer is significantly high, physicians should pay closer attention to the metastasis which reaches the serosa or beyond. Combining EUS and MMP-9 improves the accuracy in deciding the invasion and metastasis in the patients with gastric carcinoma.

Molecular mechanisms of early atrial remodeling by rapid atrial pacing in rabbits

Objective: To establish a rabbit atrial fibrillation model with rapid atrial pacing (RAP) and investigate its ultrastructural changes and expressions of L-type calcium channel subunits and potassium channel Kv4. 3. Methods: Thirty-six rabbits were performed electrical stimulation through bipolar endo-cardial led by surgical technique. 600 beat per min from 0 to 48 h. Atrial ultrastructure was observed by transmission electron microscope (TEM) after different pacing times. mRNA were measured by reverse transcription-polymera.se chain reaction (RT-PCR). Results: Atrial ultrastructure had alteration after 3 hours' pacing, such as mitochondria vacuolization, myofilament lysis and glucogen aggregation. The mRNA of the Ca2+ channel β1 and α1 subunits began to decrease after pacing of 6 h. which were paralleled with the change of Kv4. 3 mRNA. But the auxiliary subunit α2 were not affected. Conclusion: Ultrastructural changes and mRNA levels of L-type calcium channel subunits and potassium channel Kv4. 3 are decreased after RAP. with a mechanism of transcriptional down-regulation of underlying ion channels due to calcium overloading after RAP.