Three loci related to the src oncogene and tyrosine-specific protein kinase activity in Drosophila

Rous sarcoma virus (RSV) is an acutely oncogenic avian retrovirus which induces sarcomas in animals and transforms fibroblasts in cell culture. Genetic analysis indicates that the viral src gene (v-src) mediates neoplastic transformation. The product of v-src is a 60,000 molecular weight (MW) phosphoprotein (pp60v-src) possessing the enzymatic activity of a tyrosine-specific protein kinase. The viral src gene is derived from a cellular gene (c-src) which also encodes a 60,000 MW phosphoprotein (pp60c-src) with tyrosine-specific protein kinase activity. Both birds and mammals are known to possess c-src. Shilo and Weinberg have reported that the genome of the fruit fly, Drosophila melanogaster, contains nucleotide sequences that are homologous to v-src. We report here the molecular cloning and chromosomal mapping of three loci from the Drosophila genome that contain such sequences. We also show that Drosophila contain both phosphotyrosine and a tyrosine-specific protein kinase activity immunoprecipitated by antisera directed against pp60v-src. It should now be possible to identify the precise locus that encodes a src-specific protein kinase in Drosophila, and to explore the role of c-src in the growth and development of D. melanogaster.     

dDnmt2与dMBD2/3在果蝇不同发育时期的转录表达

为了深入了解果蝇DNA甲基化修饰系统及其相关基因的表达特点及功能,以黑腹果蝇Canton S品系为材料,应用实时荧光定量PCR方法检测分析不同发育时期果蝇dDnmt2与dMBD2/3基因的转录表达.结果表明:dDnmt2与dMBD2/3分别在6～9 h和0-3 h胚胎期表达量最高,在12～15 h和18～21 h胚胎、三龄幼虫、蛹、成虫期表达明显降低.果蝇dDnmt2和dMBD2/3基因的表达特点与果蝇不同发育时期基因组DNA甲基化水平相一致.     

Viral myb oncogene encodes a sequence-specific DNA-binding activity

The retroviral oncogene v-myb and its cellular progenitor c-myb encode nuclear DNA-binding proteins. Myb genes have been identified in a broad range of species, including vertebrates, the fruit fly Drosophila melanogaster and the plant Zea mays. The localization of the DNA-binding domain of the v-MYB protein to the highly conserved amino-terminal region suggests that the MYB/DNA interaction is important for MYB function. We show here that v-MYB specifically recognizes the nucleotide sequence pyAACG/TG. So like other nuclear transforming proteins, v-MYB seems to be a member of the class of sequence-specific DNA-binding factors presumably involved in gene regulation.     

果蝇新品系开发与种质资源保存

摘要: 黑腹果蝇( Drosophila melanogaster) 是当今生物医学研究领域最重要的模式生物之一。良好的饲养、高效的转基因构建和规范化的品系保存是顺利开展果蝇实验的三大基石。清华大学果蝇中心作为国内最大的果蝇资源平台,积累了丰富的果蝇操作和维护经验。本文综合介绍了清华大学果蝇中心在日常饲养、品系开发和种质保存等方面建立的标准化操作体系,旨在为广大科研同仁提供经验参考,加快我国在以果蝇为模式生物研究生物医学重大问题等领域的研究进程。     

Genetic effects of injection of Rous sarcoma virus DNA into polar plasm of early Drosophila melanogaster embryos

Retroviral proviruses and the transposable elements of eukaryotic genomes are structurally similar. The biological significance of eukaryotic transposable elements has not been examined extensively but it is known that, like prokaryotic transposons, these elements can induce mutations in adjacent genes and cause their transposition. It is of interest to determine whether retroviral proviruses have the same mutagenic and gene transposing ability as transposable elements, particularly because the retrovirus genome is assumed to have originated from transposable elements of lower eukaryotes. The transfer of DNA sequences into animal zygotes or embryos by microinjection is a promising experimental approach for eluxidating their functions: when foreign DNAs were introduced into a mouse germ line, mutations were induced and at least in some mice, the mutation was caused by the insertion of a retroviral sequence. We have introduced Rous sarcoma virus (RSV) DNA into a germ line of Drosophila melanogaster, and describe here the resultant genetic effects.     

c-Jun氨基末端激酶3结构域突变质粒的构建、鉴定与转染

为构建c-Jun氨基末端激酶3 (c-Jun N-terminal kinase3,JNK3)的p VP16-eGFP-Myc-JNK3活化环(activation-loop,A-loop)结构域突变型重组质粒,通过A-loop突变型JNK3的c DNA序列以及p VP16-eGFP-Myc的酶切位点设计引物,PCR扩增目的基因,使用限制性内切酶Mlu I与Xba I将基因克隆到p VP16-eGFP-Myc真核表达载体中,构建p VP16-eGFP-Myc-JNK3(A-loop)结构域突变型重组质粒。转化后,通过双酶切鉴定与DNA测序判断是否成功构建重组质粒,使用Trans IntroTMEL Transfection Reagent转染人胚肾(human emborynic kidney,HEK) 293T细胞,通过荧光显微镜下观察融合蛋白表达情况。结果表明:构建p VP16-eGFP-Myc-JNK3 (A-loop)结构域突变型重组质粒,双酶切鉴定和测序结果显示构建成功; p VP16-eGFP-MycJNK3 (A-loop)成功转染HEK293T细胞且表达。鼠源JNK3结构域突变型质粒构建成功,对进一步研究JNK3结构域在相关疾病的作用和机制提供实验工具。     

A conserved DNA sequence in homoeotic genes of the Drosophila Antennapedia and bithorax complexes

A repetitive DNA sequence has been identified in the Drosophila melanogaster genome that appears to be localized specifically within genes of the bithorax and Antennapedia complexes that are required for correct segmental development. Initially identified in cloned copies of the genes Antennapedia, Ultrabithorax and fushi tarazu, the sequence is also contained within two other DNA clones that have characteristics strongly suggesting that they derive from other homoeotic genes.     

北五味子对果蝇繁殖力的影响研究

研究了北五味子对果蝇繁殖力的影响.在培养基中加入不同重量的北五味子干燥果肉粗粉进行果蝇培养,在一定时间内统计完成羽化的F1、F2果蝇的数量.结果表明,与对照相比,添加北五味子的3个处理F1羽化成虫数量显著增多(P<0.05),其中,添加1%北五味子干燥果肉粗粉的处理果蝇数量较对照增加了45.75%.这表明北五味子能够显著地增强果蝇的繁殖力.本研究为果蝇的高效培养繁殖提供了科学依据.     

硫酸铈诱导果蝇氧化应激及细胞凋亡的研究

本实验主要研究了稀土硫酸铈（Ce（SO4）2）对果蝇氧化应激生物标记物和细胞凋亡的影响.果蝇培养在不同质量浓度（1,4,16,64,256,1 024 mg/L）的硫酸铈培养基中,分别测定其SOD,CAT和脂质过氧化产物（即MDA含量）,同时用彗星电泳和体外切割DNA实验来检测果蝇细胞中DNA损伤程度,用DNA Laddering法和TUNEL法测定稀土元素Ce对果蝇细胞凋亡的影响.与对照组相比,当Ce（SO4）2质量浓度低于16 mg/L时,果蝇体内SOD和CAT活性显著增加,MDA含量变化不明显;而当Ce（SO4）2质量浓度高于16 mg/L时,SOD和CAT活性明显下降,MDA含量上升.彗星电泳的结果表现为随着硫酸铈剂量的递增,果蝇中肠细胞的彗星率、彗星尾长和Olive尾矩增加,并表现为明显的剂量效应关系.果蝇体外实验结果表明,硫酸铈能打断DNA,使其片段化;同时,TUNEL结果显示果蝇中肠细胞呈现凋亡细胞的特征性蓝绿色颗粒,但DNA琼脂糖电泳没有表现出细胞凋亡特征性的梯形条带图谱.硫酸铈诱导果蝇的氧化应激可以使果蝇中肠细胞SOD和CAT活性降低,MDA含量上升,使中肠细胞出现凋亡特征.由此推断,硫酸铈可诱导果蝇细胞中遗传物质的损伤,对果蝇有一定的氧化毒性和遗传毒性作用．     

Apparent absence of transposable elements related to the P elements of D. melanogaster in other species of Drosophila

P elements are transposable elements found in P strain, but usually not in M strain, Drosophila melanogaster, and are responsible for the hybrid dysgenesis that occurs when male D. melanogaster of the P strain mate with females of the M strain (ref. 1 and references therein). Several P elements, which vary in length and genetic effects, have now been cloned. To investigate the evolutionary origin of P elements, we have used a cloned copy of a D. melanogaster P element to look for related sequences in the genomes of six other Drosophila species. We report here that, unlike many other transposable elements found in D. melanogaster, which seem also to be present in other Drosophila species, we have found no sequences closely enough related to P elements to be detected by DNA hybridization in any other Drosophila species. This result supports the hypothesis that P elements have recently invaded D. melanogaster by horizontal transmission.     

Molecular and phenotypic variation in the achaete-scute region of Drosophila melanogaster

Variation in quantitative characters underlies much adaptive evolution and provides the basis for selective improvement of domestic species, yet the genetic nature of quantitative variation is poorly understood. Many loci affecting quantitative traits have been identified by the segregation of mutant alleles with major qualitative effects. These alleles may represent an extreme of a continuum of allelic effects, and most quantitative variation could result from the segregation of alleles with subtle effects at loci identified by alleles with major effects. The achaete-scute complex in Drosophila melanogaster plays a central part in bristle development and has been characterized at the molecular level. The hypothesis that naturally occurring quantitative variation in bristle number could be associated with wild-type alleles of achaete-scute was tested by correlating phenotypic variation in bristle number with molecular variation in restriction maps in this region among chromosomes extracted from natural populations. DNA insertion variation in the achaete-scute region was found to be strongly associated with variation in bristle number.     

Distinct memory traces for two visual features in the Drosophila brain

The fly Drosophila melanogaster can discriminate and remember visual landmarks. It analyses selected parts of its visual environment according to a small number of pattern parameters such as size, colour or contour orientation, and stores particular parameter values. Like humans, flies recognize patterns independently of the retinal position during acquisition of the pattern (translation invariance). Here we show that the central-most part of the fly brain, the fan-shaped body, contains parts of a network mediating visual pattern recognition. We have identified short-term memory traces of two pattern parameters--elevation in the panorama and contour orientation. These can be localized to two groups of neurons extending branches as parallel, horizontal strata in the fan-shaped body. The central location of this memory store is well suited to mediate translational invariance.     

大果蝇（Drosophilagrandis）的形态观察和染色体研究

本文介绍了一种野生大果蝇的形态特征和染色体方面的研究结果。形态观察表明，这种野生大果蝇有许多形态特征不同于D.melanogaster，如个体较大，性柱位置不同等。染色体研究发现，此种果蝇的唾液腺染色体比D.melanogaster大得多，具有6条长臂和1条短臂，；核型为2n=12,4R 1V 1D。     

Hira基因的过量表达对果蝇早期胚胎发育的影响

Hir／Hira基因产物是组蛋白基因表达的一种负调节因子,其在果蝇发育过程中的作用还没有得到确认．本研究将果蝇Hira基因（dHira）的cDNA克隆到载体UAsP中,运用UAS—Gal4系统使其在果蝇早期胚胎中大量表达．结果发现在胚胎发育早期,无论是在头部还是在全胚胎过量表达Hira,都引起果蝇胚胎大量死亡,而且随着转基因拷贝数的增加,胚胎的死亡率也显著增加,说明Hira过量表达对果蝇胚胎发育产生严重影响．由于Hira基因产物与核小体的组装、染色质结构等的调节有关,因此推测Hira过量表达可能是通过对组蛋白的抑制对果蝇胚胎发育造成影响的．     

Pattern formation in the developing eye of Drosophila melanogaster is regulated by the homoeo-box gene, rough

Homoeo-box genes play a central role in the regulation of embryogenesis in Drosophila melanogaster. Their widespread phylogenetic distribution, and the tissue and stage specificity of their expression in other organisms, argue that they play a general and significant role in animal development. In D. melanogaster, all homoeo-box genes characterized to date are involved in major aspects of embryogenesis. We report here the molecular characterization of a Drosophila homoeo-box gene that has no apparent involvement in early embryogenesis. The gene appears to be rough, a gene implicated in pattern formation in the developing eye. It is expressed in cells within, and posterior to, the morphogenetic furrow, the site of the primary pattern forming events in the developing retina, and also in a region of the brain of the third instar larva. We have found no genetic or molecular evidence of a role for this gene in other aspects of fly development.