杉木第四号染色体特异性RAPD片段的获得

分别分离杉木(Cunninghamia lanceolata(Lamb.)Hook)同一细胞中的第四号具随体染色体及剩余20条非随体染色体,进行DOP-PCR扩增,分别以随体染色体及非随体染色体的DOP-PCR产物为模板,用成对随机引物进行RAPD分析。用引物对OPB07+OPB10进行扩增,在500-250 bp之间,随体染色体有4条特异扩增带;用引物对OPB07+OPB18在900 bp左右获得1条随体染色体特异带;用引物对OPD07+OPD05在250 bp左右得到随体染色体1条特异扩增带。     

黄鳝单条染色体的显微分离及特异性检测

建立了显微分离黄鳝单条染色体及检测其特异性的方法;在Olympus倒置显微镜下用毛细玻璃微针手工分离黄鳝减数分裂Ⅰ终变期3号染色体,将期DNA作模板进行DOP-PCR扩增后,分别以α^-32P-dCTP和Biotin-11-dUTP标记的单条染色体DNAPCR扩增产物及Biotin-11-dUTP标记的大豆18SrRNA基因作探针进行Southern杂交,FISH和Dot杂交来检测其特异性,结果表明：（1）减数分裂Ⅰ终变期染色体标本是进行染色体显微操作的理想材料;（2）DOP-PCR扩增产物片段在200-1000bp之间,平均600bp左右;（3）杂交结果显示,本研究所获得的单条染色体是黄鳝3号染色体;（4）与显微操作仪和微激光分离相比较。该方法不需要昂贵仪器,在常规实验室即可操作,具有广泛的普及应用意义。     

簇毛麦端体6VS的显微切割及其专化DNA序列的克隆和分析

从簇毛麦(Haynaldia villosa (L.) Schur.)组合CA9211/RW15(6D/6V异代换系)幼胚培养SC2后代中,用原位杂交方法鉴定出T240-6为6VS端体异代换系. 以此为材料,采用微细玻璃针切割法及"单管反应"技术体系,对6VS进行切割分离及LA (Linker adaptor)-PCR扩增.扩增带在100～3 000 bp 之间,大部分集中在600～1 500 bp.利用32P标记的簇毛麦基因组为探针进行Southern杂交,证实扩增产物来源于簇毛麦.扩增产物纯化后,连接到pGEM-T载体上,构建了6VS DNA质粒文库.对文库的分析表明,文库大约有17 000个白色克隆;插入片段分布在100～1 500 bp,平均600 bp.点杂交结果表明,37%克隆有中度到强烈的杂交信号,证明含有中度或高度重复序列;63%克隆有较弱的信号或没有信号,证明为单/低拷贝序列克隆.从文库中获得8个簇毛麦特异克隆,对其中两个克隆pHVMK22和 pHVMK134进行了RFLP分析和序列分析,并利用该探针对小麦抗白粉病基因Pm21进行了检测.RFLP 结果表明,两个克隆一个为低拷贝序列克隆(pHVMK22),另一个为高度重复序列克隆,均为簇毛麦专化DNA序列.以pHVMK22为探针对抗、感病小麦(Triticum aestivum L.)品系的Southern杂交发现抗病品系有一条2 kb的特征带, 该探针可能作为检测抗病基因Pm21的探针.     

对微分离的大豆单染色体的克隆及其PCR产物的原位杂交分析(英文)

通过玻璃针分离法从大豆 (GlycinemaxL .)根尖细胞中期分裂相中显微分离出一条染色体 ,经Sau3A人工接头介导的两轮PCR后 ,将其第二轮扩增产物克隆到质粒载体上 ,构建了单染色体质粒文库。经分析 ,该微克隆文库包含约 2 0 0 0 0 0个重组子。随机挑选 1 78个重组子进行鉴定 ,证明该文库的插入片段主要介于 2 0 0～ 1 80 0bp之间 ,平均大小 830bp ;其中 ,中、高拷贝重复序列占 44% ,单、低拷贝序列占 56%。微分离染色体体外扩增产物的原位杂交分析表明它们来自于大豆基因组 ,然而却未能将其只标记在该条微分离的染色体上     

利用染色体区段混合BAC探针鉴定食管癌细胞中的染色体畸变

染色体畸变是恶性肿瘤细胞的重要遗传学特征, 文章旨在应用BAC DNA克隆鉴定食管癌细胞中的染色体臂和染色体区段的畸变。针对染色体各区段选取5~10个1 Mb BAC DNA, 分别混合制备成特定染色体区段的BAC DNA混合克隆, 然后将染色体臂上覆盖所有区段的上述混合克隆进一步混合制备成特定染色体臂BAC DNA混合克隆。利用简并寡核苷酸引物聚合酶链反应(Degenerate oligonucleotide primed PCR, DOP-PCR)标记染色体臂探针, 利用切口平移法(Nick translation)标记染色体区段探针, 并对食管癌细胞中期染色体进行荧光原位杂交(Fluorescence in situ hybridization, FISH)分析。正常人外周血淋巴细胞中期染色体FISH结果显示, 上述方法标记的探针具有较高的特异性。进一步利用染色体臂混合探针, 确定了多个食管癌细胞中的染色体重排所涉及的特定染色体臂; 利用染色体区段混合探针, 鉴定出KYSE140的t(1q;7q)衍生染色体中1q上的断点范围位于1q32-q41。文章成功建立了1 Mb BAC DNA混合克隆探针标记技术, 并鉴定出多个食管癌细胞中的染色体臂和染色体区段畸变, 不仅为利用M-FISH技术鉴定肿瘤细胞中的染色体畸变提供了更为准确的方法, 而且还可能进一步将该法推广应用于恶性血液病的核型分析以及产前诊断。     

向日葵单染色体显微分离及特异文库的构建

采用玻璃针分离法,通过显微操作系统成功地分离到内葵杂3号三交种和单交种的随体染色体,经两轮LA．PCR扩增得到250～1500bp的DNA片段。用各自的基因组DNA标记成探针,与随体染色体扩增产物进行Southern杂交,显示杂交信号,证明内葵杂3号三交种和单交种随体染色体DNA已被成功扩增。将第2轮PCR产物构建质粒文库,得到三交种和单交种克隆数分别约为2．26×10^5和2．57×10^5。各随机挑取30个重组子进行分析,发现插入片段大小分别为200-700bp和200～500bp,平均插入片段大小分别为535bp和480bp。这是染色体微分离与微克隆技术首次在向日葵上的应用。     

刺鳅X染色体DNA文库的构建

刺鳅（Mastacembelus aculeatus）是具有明显X和Y异形性染色体分化的淡水鱼。本实验室通过显微切割（Microdissection）和兼并引物PCR（DOP-PCR）方法,从雌性刺鳅中期染色体分裂相中分离获得X染色体并扩增其DNA,利用T载体和电转化方法,建立了刺鳅X染色体DNA质粒文库。该文库插入片段的平均长度约为500bp,理论上包含X染色体98％以上的序列。当用荧光原位杂交（FISH）来验证文库的专一性时发现,在无竞争性DNA杂交条件下,整个X和Y染色体上都表现出强烈的杂交信号,并且常染色体上也出现一些随机散布信号;当含有竞争性DNA时,常染色体上的信号消失,仅性染色体上异染色质区域保留有较强信号。就此,本文对刺鳅性染色体上的序列类型进行了探讨。     

番木瓜单染色体的显微分离与克隆

用玻璃针显微分离出番木瓜(CaricapapayaL.)单染色体,经过LA-PCR扩增得到80-700bp的DNA片段。Southern杂交表明,扩增片段与番木瓜基因组DNA之间有同源性,从而证明番木瓜单染色体DNA已经被成功扩增。将扩增产物克隆到pGEM-T-Easy载体中,约获得1.18×105个克隆,酶切鉴定插入片段大小为100-400bp。     

杉木种子随体染色体SCAR标记的建立

回收、纯化由引物OPB07(5’-GGTGACGCAG-3’) OPB18(5’-CCACAGCAGT-3’)扩增而得的杉木(Cunninghamia lanceolata(Lamb.)Hook)种子随体染色体特异性RAPD(随机扩增的DNA多态性分析)片段OPB07-18907,将该片段克隆至pUCm-T载体,转化受体菌后筛选出阳性克隆,并对插入片段进行测序,根据序列特点设计两对SCAR(序列特异性扩增区)引物,PCR结果显示,这两对引物的4种组合都可以扩增出属于随体染色体的特征带,适宜退火温度为57℃。成功将特异RAPD标记OPB07-18907转化为稳定的SCAR标记。开发随体染色体SCAR标记目的是:一方面能在分子水平上鉴定微分离的杉木随体染色体,另一方面,也可以将杉木已构建的遗传图谱中连锁群与染色体进行对应。探讨了该SCAR标记对杉木核型分析的作用。     

Removal of repetitive sequences from FISH probes using PCR-assisted affinity chromatography

The vast majority of probes used in fluorescence in situ hybridization (FISH) contain repetitive DNA. This DNA is usually competed out of a hybridization reaction by the addition of an unlabeled blocking agent, Cot-1 DNA. We have successfully removed repetitive DNA from two complex FISH probe sets: a degenerate oligonucleotide-primed polymerase chain reaction (DOP-PCR) single human chromosome library and genomic DNA. The procedure involved hybridizing in solution a DOP-PCR-amplifiable probe set with a 50-fold excess of biotin-labeled Cot-1 DNA, and capturing the Cot-1 DNA-containing hybrids using streptavidin magnetic particles, followed by purification and reamplification of the unbound fraction. Probes were checked for depletion of repeats by hybridization to chromosomes without Cot-1 DNA. Results showed hybridization patterns comparable to those achieved with untreated probes hybridized with Cot-1 DNA. Received: 21 January 1997 / Accepted: 2 April 1997     

Microdissection of M chromosome in Vicia faba and its library construction]

Microdissection and microcloning technique was employed to construct the library of M chromosome in Vicia faba. The M chromosomes were microdissected with a micromanipulator and were put into a 0.5 ml Eppendorf tube, then digested with Sau3A. Sau3A linker adaptors were ligated to the end of chromosome DNA fragments, and two rounds of PCR were carried out with one chain of linker adaptor as the primer. The PCR products ranged in size from 300 base pair (bp) to 3000 bp with predominant fragments from 500 bp to 1500 bp. Southern hybridization analysis confirmed that PCR products originated from Vicia faba genome. The second round PCR products were cloned and about 102,000 recombinants were obtained. 118 recombinants were selected randomly for analysis. The inserts ranged in size from 150 bp to 3000 bp with an average of 690 bp. Dot blot was carried out for 100 clones with DIG labeled Vicia faba genome DNA as probes. The result revealed that 51% were low and unique copy sequences, 49% were repetitive sequences. M chromosome DNA library has not been reported before.     

Development of microdissection and chromosome specific genomic library in Lilium tigrinum

Techniques for microdissection and microcloning were established using chromosome 1 of triploid Lilium tigrinum. Chromosome 1 was dissected from a membrane slide using a microbeam system. Digestion with proteinase K was done before PCR amplification for more than 24 hours. The dissected chromosomes were then amplified by degenerate oligonucleotide primed PCR (DOP-PCR) and linker adaptor-mediated PCR (LA-PCR). Successful PCR amplification relied on critical concentrations of both MgCl₂ and Taq polymerase. The optimum concentration of MgCl₂ and Taq polymerase was 2.5 mM and 0.5 U, respectively. Amplification of the dissected chromosome using DOP-PCR had more sensitivity dependent upon PCR factors, but LA-PCR was more dependent on the linker ligation. Amplified DNA products ranged from 100 to 2500 bp both for DOP- and LA-PCR. Evaluated clones only ranged from 100 to 1700 bp for DOP-PCR and 100 to 900 bp for LA-PCR. Based on the sequence results, most of the sequences from the DOP-PCR and LA-PCR showed no significant similarity with known data in NCBI database. However, about 2% of the sequence data was partially matched with plant microsatellites with low similarity. The results derived from the microdissection of a large genome organism such as Lilium showed informative and useful for the development of microsatellite repeat markers. Sequence data from the chromosome specific DNA library was considered for the development of microsatellite markers.     

mini-质粒筛选大鼠基因组库

两个雄激素相关的pBR322克隆的cDNA插入片段,克隆到mini-质粒πAN7,再由词源顺序互补重组的方式,整合到Charon 4A大鼠肝基因组库的噬茵体DNA中。由此筛选的πDNA克隆经遗传学试验和点杂交确证。此外,限制性酶解和Southern杂交分析推演出该两基因组片段的大致物理图谱。对于应用πAN7质粒筛选基因组库的原理及优缺点,本文作了简要的讨论。     

Cloning of DNA sequences localized on proximal fluorescent chromosome bands by microdissection in Pinus densiflora Sieb. & Zucc.

Japanese red pine, Pinus densiflora, has 2n=24 chromosomes, of which most carry chromomycin A3 (CMA) and 4',6-diamidino-2-phenylindole (DAPI) bands at their centromere-proximal regions. It was proposed that these regions contain highly repetitive DNA. The DNA localized in the proximal fluorescent bands was isolated and characterized. In P. densiflora, centromeric and neighboring segments of the somatic chromosomes were dissected with a manual micromanipulator. The centromeric DNA was amplified from the DNA contained in dissected centromeric segments by degenerate oligonucleotide primed-polymerase chain reaction (DOP-PCR) and a cloned DNA library was constructed. Thirty-one clones carrying highly repetitive DNA were selected by colony hybridization using Cot-1 DNA from this species as a probe, and their chromosomal localization was determined by fluorescent in situ hybridization (FISH). Clone PDCD501 was localized to the proximal CMA band of 20 chromosomes. This clone contained tandem repeats, comprising a 27 bp repeat unit, which was sufficient to provide the proximal FISH signal, with a 52.3% GC content. The repetitive sequence was named PCSR (proximal CMA band-specific repeat). Clone PDCD159 was 1700 bp in length, with a 61.7% AT content, and produced FISH signals at the proximal DAPI band of the remaining four chromosomes. Four clones hybridized strongly to the secondary constriction and gave weak signals at the centromeric region of several chromosomes. Clone PDCD537, one of the four clones, was homologous to the 26S rRNA gene. A PCR experiment using microdissected centromeric regions suggested that the centromeric region contains 18S and 26S rDNA. Another 24 clones hybridized to whole chromosome arms, with varying intensities and might represent dispersed repetitive DNA.     

黑麦1R染色体的显微分离、体外扩增及扩增产物的鉴定

借助Leitz显微操作器,在国产倒置显微镜下(400×)用玻璃针对处于有丝分裂中期的黑麦根尖细胞中的1R染色体成功地进行了分离。分离出来的1R染色体转入0.5 ml的Eppendorf管中,用蛋白酶K处理,把DNA释放出来;经Sau3A酶切,再与人工合成的Sau3A连接头连接;以连接头的一条链的核苷酸顺序片段为引物对DNA酶切片段进行了PCR扩增。琼脂糖凝胶电泳显示扩增产物的长度大约为300~1000 bp。以生物素分别标记的黑麦总体DNA和小麦rDNA为探针进行斑点杂交,结果表明PCR扩增产物确实来源于黑麦的1R染色体DNA。这个方法为构建黑麦1R染色体亚基因组文库和筛选1R染色体特异性探针奠定了基础。     

Construction and analysis of an EMBL-3 phage library containing partially digested human chromosome 21-specific DNA inserts (15-20 kb)

In the mouse-human hybrid cell line SCC 16-5, chromosome 21 is the only human chromosome present. Fractions highly enriched for this chromosome were obtained by applying the chromosome velocity sedimentation technique to this cell line. DNA prepared from these chromosomal fractions was partially digested with Mbo I, size fractionated on an NaCl gradient, and cloned in the EMBL-3 phage vector. The phage library thus prepared was highly enriched for human chromosome 21-specific recombinant DNA sequences 15-20 kb long. Of the approximately 21,000 phage clones obtained, at least 99% were recombinant. Following phage plaque filter hybridization and Southern blotting, it was found that half of the recombinants were positive for human repetitive DNA. Almost all phages harbored highly or middle repetitive human or mouse DNA sequences owing to the large size of the recombinant inserts. In this library, the human chromosome 21 is represented approximately four times. All human recombinants studied thus far contained DNA inserts originating from chromosome 21 only. The employed cloning strategy is discussed with regard to utility, purity, quality, and completeness of chromosome-specific recombinant DNA libraries.     

水仙单染色体特异文库的构建

采用玻璃针分离法,通过显微操作系统成功地分离到一个多花水仙(N arcissus tazetta L.,2n=22)品种的中着丝粒单染色体,将分离到的单染色体放入0.2 mL Eppendorf管中,经去蛋白、S au3A酶切,并在染色体DNA片段两端加上S au3A人工接头后,进行两轮PCR扩增,得到0.3~3.0 kb之间的DNA片段.用水仙基因组DNA标记作探针,与扩增产物进行Sou thern杂交,从而证明单染色体DNA确实已被成功地扩增.将第二轮PCR产物构建质粒文库,随机挑取90个重组子进行分析,发现插入片段主要在600~2 500 bp之间.