Expression of Chx10 and Chx10-1 in the developing chicken retina

We have isolated full-length cDNAs of chick Chx10 and Chx10-1, two members of the paired type homeobox/CVC gene family. A comparison of sequences suggests that Chx10 is closely related to Alx/Vsx-2 and Vsx-2 of zebrafish and goldfish, respectively; while Chx10-1 is closely related to Vsx-1 of zebrafish and goldfish. Chx10 and Chx10-1 are expressed in the early retinal neuroepithelium, but not in the pigment epithelium and lens. The expression of Chx10 is present in most retinal neuroblasts, while Chx10-1 exhibits a novel pattern along the nasotemporal border. In the differentiating retina, both Chx10 and Chx10-1 are restricted to bipolar cells and are maintained at a low level in bipolar cells of the mature retina.     

Tissue-specific expression of the chalcone synthase multigene family in Phaseolus vulgaris: development of a RT-PCR method for the expression profiling of the chs isogenes

Chalcone synthase is a key metabolic control point in the biosynthesis of a large number of flavonoids and isoflavonoid metabolites. Chs genes in bean comprise a multigene family, of which certain individual members can be differentially induced with respect to kinetics and extent of accumulation. A RT-PCR technique, based on primers designed complementary to a common conserved region and divergent 3′ sequences of the bean chs family, was developed to detect the expression of individual members of the chs family. The semi-quantitative technique is based on the amplification of short, overlapping sequences differing in size. The method was found to be sensitive, rapid, and capable of distinguishing among the individual chs members (chs 1, 4, 14, and 17). The tissue-specific expression of chs isogenes in bean seedlings, flowers and callus, as well as the effect of light on chs expression in etiolated tissue was documented.     

应用基因芯片技术对疲劳性运动小鼠脑组织脂肪酸代谢相关基因表达的初步研究

目的:采用基因芯片技术分析硬脂酰基-辅酶A去饱和酶2(Scd-2)基因和脑型脂肪酸结合蛋白(B-FABP)基因在疲劳小鼠脑组织中的表达,从基因水平探讨脂类代谢对运动性中枢疲劳产生影响的分子生物学机制.方法:建立疲劳性运动动物模型,应用基因芯片技术对运动性疲劳小鼠脑组织中基因的表达进行分析.结果:疲劳性运动小鼠脑组织中与脂肪酸代谢相关的基因Scd-2和B-FABP显著差异表达.结论:产生运动性中枢疲劳与脂肪代谢相关的蛋白分子基因表达有关联,具有高通量、并行性、快速、准确等优点的基因芯片技术在运动性疲劳机制研究中有广阔的应用前景.     

Gsh-2, a murine homeobox gene expressed in the developing brain

A novel murine dispersed homeobox gene, designated Gsh-2, is described. Analysis of cDNA sequence, including the full open reading frame, reveals an encoded homeodomain that is surprisingly similar to those of the Antennapedia-type clustered Hox genes. In addition, the encoded protein includes polyhistidine and polyalanine tracts, as observed for several other genes of developmental significance. In situ hybridizations showed Gsh-2 expression in the developing central nervous system, including the ganglionic eminences of the forebrain, the diencephalon, which gives rise to the thalamus and hypothalamus, and in the hindbrain. Furthermore, a random oligonucleotide selection and PCR amplification procedure was used to define a target DNA binding sequence, CNAATTAG, as a first step towards the identification of downstream target genes.     

家蚕醛氧化酶基因（BmAOXs）的鉴定与表达分析

醛氧化酶（aldehyde oxidases, AO, EC 1.2.3.1）是属于钼-黄素酶（molybdo-flavoenzymes, MFEs）家族的一类蛋白酶。为了探讨该酶在家蚕Bombyx mori中的功能, 本研究对家蚕醛氧化酶基因（BmAOXs）家族进行了鉴定和分析。以其他物种AO基因序列检索家蚕全基因组数据库, 获得了8个BmAOX候选基因, 均具有醛氧化酶保守的功能域。进化分析表明, BmAOX与其他昆虫AO聚为一簇。RT-PCR分析结果显示: BmAOX1, BmAOX2, BmAOX3, BmAOX5具有很强的组织特异性; 而BmAOX4, BmAOX6, BmAOX7, BmAOX8则在蛹和成虫的多个组织中均有表达, 提示它们在家蚕生理代谢活动中起重要作用。利用Native PAGE和活性染色方法, 对BmAOX编码的蛋白进行检测, 结果表明: 家蚕蛹中有5种有活性的醛氧化酶, 而成虫中有6种, 各组织中均有有活性的BmAOX, 只是种类和活性水平有所不同。本研究结果为深入探讨BmAOX家族的功能奠定了基础。     

Identification and expression analysis of kcnh2 genes in the zebrafish

Long QT syndrome is a disorder that is characterised by a prolonged QT-interval and can lead to fatal cardiac arrhythmias. Many animal models have been created to study congenital long QT syndrome. Of these, zebrafish models have involved targeting two different KCNH2 gene (long QT syndrome 2) orthologues, termed zerg-2 and zerg-3, with differing cardiac phenotypes. In order to clarify this situation, this study uses a bioinformatic approach to search the current zebrafish genome sequence (Zv7 and Zv8 builds) to investigate and locate all likely zebrafish orthologues of the human KCNH2 gene. Quantitative real-time RT-PCR was also used to determine the temporal and spatial gene expression profile of the zebrafish orthologues. The data support the conclusion that zerg-2 and zerg-3 are apparent orthologues of different human genes encoding potassium ion channels, but that their functions have switched compared to the respective human proteins.     

Cloning, sequencing and enhanced expression of the Trichoderma reesei endoxylanase II (pI 9) gene xln2

The Trichoderma reesei xln2 gene coding for the pI 9.0 endoxylanase was isolated from the wild-type strain QM6a. The gene contains one intron of 108 nucleotides and codes for a protein of 223 amino acids in which two putative N-glycosylation target sites were found. Three different T. reesei strains were transformed by targeting a construct composed of the xln2 gene, including its promoter, to the endogenous cbh1 locus. Highest overall production levels of xylanase were obtained using T. reesei ALK02721, a genetically engineered strain, as a host. Integration into the cbh1 locus was not required for enhanced expression under control of the xln2 promoter.     

马铃薯甲虫结节性硬化复合物基因LdTSC1和LdTSC2基因的克隆及功能分析

【目的】通过RNAi技术明确马铃薯甲虫TOR上游的关键信号集成节点及类胰岛素信号通道下游基因结节性硬化复合物TSC1和TSC2的功能。旨在为探明马铃薯甲虫类胰岛素信号转导提供更多理论支持。【方法】在NCBI(美国国家生物技术信息中心)获取马铃薯甲虫LdTSC1/2序列,分别利用多重序列比对和系统发育分析确定该基因的完整性和系统发育关系;采用喂食幼虫dsRNA的方法,观察该基因的调低对马铃薯甲虫幼虫生长发育、糖脂代谢的影响。【结果】克隆得到马铃薯甲虫TSC1编码蛋白的氨基酸序列与鞘翅目白蜡窄吉丁直系同源蛋白的氨基酸序列的自展一致度为100%,聚为一支;TSC2编码蛋白的氨基酸序列与鞘翅目白蜡窄吉丁和赤拟谷盗的同源蛋白氨基酸序列的自展一致度为100%,聚为一支。通过分别喂食2龄幼虫LdTSC1/2的dsRNA能有效降低靶标基因的表达量,幼虫出现体重减轻,化蛹率和羽化率显著下降,葡萄糖的吸收转化效率降低,海藻糖含量升高和甘油三酯均减少。【结论】下调2龄幼虫LdTSC1/2的表达量,导致试虫出现抑制了糖脂代谢、脂肪体减少、体重减轻以及发育延迟;结果表明LdTSC1/2调控了马铃薯甲虫幼虫的糖脂代谢过程,显著影响幼虫化蛹和蜕皮过程。     

高粱高亲和硝酸盐转运蛋白NRT2/3基因家族鉴定、表达与DNA变异分析

硝态氮是作物吸收无机氮素的主要形态,硝酸盐转运蛋白2(nitrate transporter 2,NRT2)作为高亲和性的转运蛋白,以硝酸盐作为特异性底物,在可利用的硝酸盐受限时,高亲和性转运系统被激活,在硝酸盐吸收、转运过程中发挥着重要作用。大多数NRT2不能单独转运硝酸盐,需在硝酸盐同化相关蛋白2(nitrate assimilation related protein 2,NAR2)的协助下才能完成硝酸盐的吸收或转运。作物氮利用效率受环境条件影响,品种间存在差异,因此培育高氮素利用效率品种有重大意义。高粱(Sorghum bicolor)具有耐贫瘠特性,对土壤中的氮素吸收和利用效率较高。本研究结合高粱基因组数据库对NRT2/3基因家族成员基因结构、染色体定位、理化性质、二级结构与跨膜结构域、信号肽与亚细胞定位、启动子区顺式作用元件、系统进化、单核苷酸多态性(single nucleotide polymorphism,SNP)的识别与注释及选择压力进行了全面分析。通过生物信息学分析,筛选出5个NRT2s(命名为SbNRT2-1a、2-1b、SbNRT2-2–4)基因和2个NAR2s(SbNRT3-1–2)基因,较谷子略少。分布在3条染色体上,分为4个亚家族,同一亚族中基因结构高度相似;高粱NRT2/3亲水性平均值均为正值,表明均为疏水性蛋白;α-螺旋和无规则卷曲占二级结构总量的比例大于70%;亚细胞定位均在质膜上,其中NRT2s蛋白不含信号肽,NRT3s蛋白含信号肽;进一步对其跨膜结构域进行分析,发现NRT2s家族成员跨膜结构域个数均大于10个,而NRT3s家族成员跨膜结构域个数为2个;高粱与玉米(Zea mays)NRT2/3s的共线性较好;蛋白结构域显示存在MFS_1和NAR2蛋白结构域,可执行高亲和力硝酸盐转运;系统进化树分析可知,高粱与玉米和谷子的NRT2/3基因亲缘关系更近;基因启动子顺式作用元件分析发现,SbNRT2/3基因的启动子区均具有数个植物激素和逆境应答元件,可以响应高粱生长和环境变化;基因表达热图显示低氮条件下在根诱导表达的是SbNRT2-1a、SbNRT2-1b和SbNRT3-1,推测可在高粱根部表达并调控对硝酸盐的吸收或转运过程。在SbNRT2-4和SbNRT2-1a等发现多个非同义SNP变异;选择压力分析表明,高粱NRT2/3基因家族在进化过程中受纯化选择作用。SbNRT2/3基因表达及蚜虫侵染影响与基因在不同组织中的表达分析结果一致,SbNRT2-1b和SbNRT3-1在感染蚜虫品系5-27sug根部表达显著,高粱蚜虫侵染叶片显著降低了SbNRT2-3、SbNRT2-4和SbNRT3-2的表达水平。本研究初步对高粱全基因组NRT2/3基因家族进行鉴定、表达与DNA变异分析,为高粱氮高效研究提供了基础。