Clustering of leukocyte and fibroblast interferon genes of human chromosome 9

At least ten leukocyte interferon genes and the single known fibroblast interferon gene have been localized on the pter leads to q12 region of human chromosome 9. Gene mapping was accomplished by blot hybridization of cloned interferon complementary DNA to DNA from human-mouse cell hybrids with a translocation involving human chromosome 9. Supporting evidence suggests these genes are clustered.     

A DNA segment encoding two genes very tightly linked to Huntington's disease

The discovery of D4S10, an anonymous DNA marker genetically linked to Huntington's disease (HD), introduced the capacity for limited presymptomatic diagnosis in this late-onset neurodegenerative disorder and raised the hope of cloning and characterizing the defect based on its chromosomal location. Progress on both fronts has been limited by the absence of additional DNA markers closer to the HD gene. An anonymous DNA locus, D4S43, has now been found that shows extremely tight linkage to HD. Like the disease gene, D4S43 is located in the most distal region of the chromosome 4 short arm, flanked by D4S10 and the telomere. In three extended HD kindreds, D4S43 displays no recombination with HD, placing it within 0 to 1.5 centimorgans of the genetic defect. Expansion of the D4S43 region to include 108 kilobases of cloned DNA has allowed identification of eight restriction fragment length polymorphisms and at least two independent coding segments. In the absence of crossovers, these genes must be considered candidates for the site of the HD defect, although the D4S43 restriction fragment length polymorphisms do not display linkage disequilibrium with the disease gene.     

Systemic lupus erythematosus: presence in human serum of an unusual acid-labile leukocyte interferon

A previously undescribed species of human leukocyte, or alpha, interferon is present in the serum of many patients with systemic lupus erythematosus. It was shown to be alpha-interferon by neutralization with specific antiserums, affinity column chromatography, and antiviral activity on bovine cells. However, 23 of 30 interferon samples tested were inactivated by incubation at pH 2, a characteristic of human "immune," or gamma, interferon. Multiple samples of interferon from the same patient had similar biological properties, but samples from different patients were not all identical, suggesting that several variants of this species of human alpha-interferon may exist.     

百子莲2个ARF基因与2个Aux/IAA基因的全长克隆与序列分析

采用不同浓度外源生长素类调节物质毒莠定(PIC)对百子莲(Agapanthus praecox ssp. orientalis)进行继代培养,并对其胚性愈伤组织进行比较转录组学研究,获得了百子莲生长素信号转导途径中的2个ARF和2个Aux/IAA家族基因,推测其为体胚发生过程中生长素信号传导途径相关的重要调控因子。采用RACE技术获得ApARF1、ApARF2、ApAux/IAA2与ApAux/IAA3的cDNA全长,分别为2 343、2 888、1 034和821 bp,开放阅读框(ORF)长度分别为1 770、2 349、480和549 bp,分别编码589、782、159和182个氨基酸残基。生物学分析表明,ApARF1与ApARF2蛋白均具有ARF家族的典型结构,ApAux/IAA2蛋白结构域Ⅳ不完整,ApAux/IAA3结构域Ⅱ部分缺失,但仍具有Aux/IAA蛋白的典型功能。转基因实验表明,ApAux/IAA过表达植株表现出生长延缓及发育受阻的表型,ApARF过表达植株表现出生长促进、花期提前的表型,验证了百子莲ApARF和ApAux/IAA家族蛋白对植物生长发育的调控作用。     

大鲵2个Sox基因HMG–box的克隆及分析

为探明Sox基因在物种进化中的保守性及其性别分型,以大鲵雌、雄个体为材料,参照Sox基因HMG-box保守区的序列,设计简并引物扩增,两因子均在雌、雄个体内得到217 bp PCR扩增产物,不存在性别差异.将二者编码的氨基酸序列与NCBI中其他物种Sox基因编码的氨基酸序列进行比对,其中一个基因与人、斑马鱼、家鼠、鸡、热带爪蟾、扬子鳄Sox11基因的同源性均为90％.另一个基因与罗非鱼、鸭嘴兽、家鼠、红鳍东方鲀、斑马鱼、鸡、人、非洲爪蟾和大鲵Sox14基因的同源性均为90％,故根据大鲵的学名,将这2个基因分别命名为adSox11和adSox14c.adSox11和adSox14c在大鲵精巢、卵巢、肾脏和心脏中均有不同程度表达,而在胃和肝脏中几乎不表达.     

两种乌鲂科鱼类线粒体DNA片段序列的比较分析

为检测日本乌鲂Brama japonica与斯氏长鳍乌鲂Taractichthys steindachneri的种间遗传差异,对线粒体16S rRNA、细胞色素b(Cytb)和细胞色素氧化酶Ⅰ(COⅠ)基因片段序列进行了测定。经比对获得同源片段序列的长度分别为491、478、558 bp,其中16S rRNA基因片段上存在2处碱基插入/缺失。核苷酸组成分析结果表明:日本乌鲂与斯氏长鳍乌鲂在这3个基因片段上的G+C含量差异不显著(P>0.05)(平均为47.27%、46.59%),G含量均偏低,特别是在Cytb和COⅠ这两个基因的第三密码子位点上表现尤为突出(平均为9.80%、12.31%)。两种鱼类在线粒体基因组不同片段上的遗传差异比较明显,在总长度为1529 bp的核苷酸序列中,两种间共检测到204处核苷酸替换,两个蛋白质编码基因上的核苷酸替换主要发生在第三密码子位点上;两种鱼类在3个基因片段上的种间净遗传距离依次为0.112 7(16S rRNA)、0.166 4(Cytb)和0.135 3(COⅠ),遗传差异水平均达到属间差异水平。NJ系统树显示,斯氏长鳍乌鲂与小鳞异鲂Xenobrama microlepis的亲缘关系较近,而与日本乌鲂的亲缘关系较远。根据Cytb基因片段序列分析,日本乌鲂与斯氏长鳍乌鲂的分歧时间约为832万年,两种间分化事件发生在中新世。     

转人干扰素α-2b细胞株建立及其外源基因表达分析

[目的]从细胞水平探讨应用水牛乳腺生物反应器生产人干扰素α-2b(IFNα-2b)的可行性,为水牛乳腺生物反应器的制备提供参考依据.[方法]建立并优化核转染人乳腺癌细胞Bcap-37的方法,再利用该方法将水牛乳腺特异性表达人IFNα-2b载体导入Bcap-37细胞,建立转基因细胞株,然后分别从RNA水平和蛋白质水平对其能否正常表达人IFNα-2b进行分析.[结果]电压是影响Bcap-37细胞核转染效率的关键因素,对其进行优化(电压275 V、电击时间10 ms)后的核转染效率可达81.1％.使用优化后的核转染方法可将水牛乳腺特异性表达载体pBCN-IFN-CMV-EGFP-neo和pBCN-IFN-CMV-EGFP-IRES-neo成功转入Bcap-37细胞而获得转人IFNα-2b细胞株,经IFNα-2b基因的mRNA表达丰度及IFNα-2b蛋白的Western blotting检测,证实在两株转基因细胞系中均能顺利进行IFNα-26基因的转录与翻译.[结论]建立的核转染法能高效转染Bcap-37细胞,可应用该方法在细胞水平上对携带人IFNα-2b基因水牛乳腺特异性表达载体的表达能力进行分析,并证实乳腺特异性表达载体(pBCN-IFN-CMV-EGFP-neo和pBCN-IFN-CMV-EGFP-IRES-neo)均能用于水牛乳腺生物反应器的制备.     

Three distinct genes in human DNA related to the transforming genes of mammalian sarcoma retroviruses

Southern blot hybridization was used to identify human and other vertebrate DNA sequences that were homologous to cloned DNA fragments containing the oncogenic nucleic acid sequences of three different type C mammalian retroviruses (simian sarcoma virus, the Snyder-Theilen strain of feline sarcoma virus, and the Harvey strain of murine sarcoma virus). Each onc gene counterpart has a single genetic locus, which probably contains non-onc intervening sequences. The human DNA sequences may represent genes important to cell growth or cell differentiation, or both. Their identification and isolation may allow elucidation of their role in these processes and in neoplasias.     

Complementary DNA sequencing: expressed sequence tags and human genome project

Automated partial DNA sequencing was conducted on more than 600 randomly selected human brain complementary DNA (cDNA) clones to generate expressed sequence tags (ESTs). ESTs have applications in the discovery of new human genes, mapping of the human genome, and identification of coding regions in genomic sequences. Of the sequences generated, 337 represent new genes, including 48 with significant similarity to genes from other organisms, such as a yeast RNA polymerase II subunit; Drosophila kinesin, Notch, and Enhancer of split; and a murine tyrosine kinase receptor. Forty-six ESTs were mapped to chromosomes after amplification by the polymerase chain reaction. This fast approach to cDNA characterization will facilitate the tagging of most human genes in a few years at a fraction of the cost of complete genomic sequencing, provide new genetic markers, and serve as a resource in diverse biological research fields.     

DNA 条形码在山茶属近缘植物鉴别中的应用

山茶属(Camellia)是山茶科(Theaceae)中物种丰富、经济效益较高的属.分类学上对山茶属的亚属、组以及种的划分争议较大,著名的3大山茶属植物分类系统分别由Sealy、张宏达和闵天禄提出.DNA条形码技术是指通过对植物基因组中的特定基因进行片段扩增、测序发现其碱基变化规律的技术手段,在分类学研究中显示出巨大的应用潜力.选取trnH-psbA和matK序列的通用引物,对山茶属不同植物基因组DNA进行扩增和序列测定,分别得到了ttrnH-psbA序列和marK序列各61条,山茶属matK序列相似度极高(98.40％),物种分辨率较低.trnH-psbA的属间物种分辨能力达到100％,而在山茶属内物种分辨率仅为13.11％.结果表明:trnH-psbA序列能够有效地区分不同属间的植物,但种间分类能力较弱.     

胡杨中两个新DREB类基因的克隆、序列分析及转录激活功能研究

DREB转录因子(干旱应答元件结合因子)是逆境适应中的关键调节因子。该类转录因子的特点是拥有保守的AP2/EREBP(APETALA2/乙烯应答元件结合蛋白)结构域,能够特异性地与抗逆基因启动子上的DRE元件相结合,在低温、干旱和盐碱等条件下调节一系列下游逆境应答基因的表达。本研究从胡杨中分离出2个编码DREB2类蛋白的基因PeDREB3和PeDREB4。PeDREB3和PeDREB4在胡杨根、茎、叶中都有表达。序列分析显示,PeDREB3和PeDREB4均含有非典型性AP2/ERF结构域,即在AP2/EREBP结构域的第2个β折叠和第3个β折叠处多出8个氨基酸残基,用改进的酵母单杂交技术发现PeDREB3和PeDREB4能够在酵母中激活下游报告基因的表达,具有转录活性。     

Molecular cloning of two types of GAP complementary DNA from human placenta

The ras p21 GTPase-activating protein (GAP) was purified from human placental tissue. Internal amino acid sequence was obtained from this 120,000-dalton protein and, by means of this sequence, two types of complementary DNA clones were isolated and characterized. One type encoded GAP with a predicted molecular mass of 116,000 daltons and 96% identity with bovine GAP. The messenger RNA of this GAP was detected in human lung, brain, liver, leukocytes, and placenta. The second type appeared to be generated by a differential splicing mechanism and encoded a novel form of GAP with a predicted molecular mass of 100,400 daltons. This protein lacks the hydrophobic amino terminus characteristic of the larger species, but retains GAP activity. The messenger RNA of this type was abundantly expressed in placenta and in several human cell lines, but not in adult tissues.     

稻瘟病抗性基因Pi-1连锁SSR标记的筛选和应用

根据稻瘟病抗性基因Pi 1在水稻物理图谱和水稻微卫星 (SSR)遗传图谱上的位置信息,获得在抗性供体亲本(LAC23)与受体亲本(珍汕 97B、金山B 1和金山S 1)间扩增产物表现出多态性的SSR标记MGR4766,它与Pi 1的遗传距离仅为 1. 3cM;分子标记辅助选择选择准确性验证表明:RM224对Pi 1选择的准确率可达 90%以上,而MRG4766对Pi 1选择的准确率为 98% -100%;同时利用RM224和MRG4766对Pi 1选择的准确率高达 100%.     

A sequence in M13 phage detects hypervariable minisatellites in human and animal DNA

The term "DNA fingerprint" has been used to describe the extensive restriction fragment length polymorphism associated with hypervariable minisatellites present in the human genome. Until now, it was necessary to hybridize Southern blots to specific probes cloned from human genomic DNA in order to obtain individual-specific restriction patterns. The present study describes the surprising finding that the insert-free, wild-type M13 bacteriophage detects hypervariable minisatellites in human and in animal DNA, provided no competitor DNA is used during hybridization. The effective sequence in M13 was traced to two clusters of 15-base pair repeats within the protein III gene of the bacteriophage. This unexpected use of M13 renders the DNA fingerprinting technology more readily available to molecular biology laboratories.     

Comment on "Widespread RNA and DNA sequence differences in the human transcriptome"

Li et al. (Research Articles, 1 July 2011, p. 53; published online 19 May 2011) reported large numbers of differences between DNA and messenger RNA in human cells, indicating unprecedented levels of RNA editing, and including sequence changes not produced by any of the known RNA editing mechanisms. However, common sources of systematic errors in high-throughput sequencing technology, which were not properly accounted for in this study, explain most of the claimed differences.     

rRNA基因间隔区序列用于亲缘关系密切的根瘤菌种群鉴定及系统发育分析

通过rRNA基因内转录间隔区的碱基序列分析,对中华根瘤菌属Sinorhizobium、慢生根瘤菌属Bradyrhizobium和中慢生根瘤菌属Mesorhizobium种间亲缘关系十分密切的菌株进行区分．结果表明,rRNA基因间隔区序列能很好地区分种间亲缘关系十分密切的菌株．用rRNA基因间隔区序列构建的系统发育树与rRNA基因序列构建的系统发育树结果十分相似．     

基于mtDNA控制区2个地方鸡品种遗传多样性及起源研究

为探讨我国2个地方蛋鸡品种仙居鸡和白耳黄鸡遗传多样性和起源进化,以30只仙居鸡和30只白耳黄鸡为素材,通过PCR扩增和测序技术,对其进行线粒体DNA控制区全序列单倍型和遗传多样性分析,并结合GenBank公布的19条红色原鸡D-loop区全序列,构建系统发育树.结果 表明:2个鸡品种变异区集中在第167-1 215 b...