Identification and characterization of the protein encoded by the human N-myc oncogene

The human N-myc gene is related to the c-myc proto-oncogene, and has been shown to have transforming potential in vitro. Many studies have reported amplification of N-myc in human neuroblastoma and retinoblastoma cell lines. In primary tumors, amplification of the gene was found to correlate directly with behavior of the tumor. Specific restriction fragments of a partial complementary DNA clone of N-myc from LA-N-5 human neuroblastoma cells were placed into a bacterial expression vector for the purpose of producing antigens representative of the N-myc protein. Rabbits immunized with these antigens produced antisera that recognized a protein of 62-64 kilodaltons in neuroblastoma cells. By several criteria, this protein appears to be part of the same proto-oncogene family as the c-myc protein. Moreover, the antisera to fragments of this protein were capable of histochemically identifying malignant cells in clinical specimens.     

Activated expression of the N-myc gene in human neuroblastomas and related tumors

In neuroblastoma lines in which the N-myc gene is present as a single copy, the expression of N-myc as messenger RNA is increased relative to that in nonneuroblastoma cell lines and tumors. The increase of expression in neuroblastomas with amplified N-myc genes is the result of (i) an increase in the absolute amount of expression of each N-myc gene and (ii) an increase in the copy number of the N-myc gene. A second gene--which is amplified in many of the same lines as N-myc--is expressed to about the same degree in most human cell lines and primary tumors regardless of origin (when normalized to gene copy number). Thus, a change in the regulation of N-myc expression in neuroblastomas and certain other tumors results in greatly increased expression of each N-myc gene copy.     

Human breast cancer: correlation of relapse and survival with amplification of the HER-2/neu oncogene

The HER-2/neu oncogene is a member of the erbB-like oncogene family, and is related to, but distinct from, the epidermal growth factor receptor. This gene has been shown to be amplified in human breast cancer cell lines. In the current study, alterations of the gene in 189 primary human breast cancers were investigated. HER-2/neu was found to be amplified from 2- to greater than 20-fold in 30% of the tumors. Correlation of gene amplification with several disease parameters was evaluated. Amplification of the HER-2/neu gene was a significant predictor of both overall survival and time to relapse in patients with breast cancer. It retained its significance even when adjustments were made for other known prognostic factors. Moreover, HER-2/neu amplification had greater prognostic value than most currently used prognostic factors, including hormonal-receptor status, in lymph node-positive disease. These data indicate that this gene may play a role in the biologic behavior and/or pathogenesis of human breast cancer.     

Gene amplification of c-myc and N-myc in small cell carcinoma of the lung

The relationship of the copy numbers of the c-myc and N-myc oncogenes to tumor formation and progression was studied in small cell carcinoma of the lung. When 96 neoplastic lesions from 45 patients were examined, these lesions could be grouped into three categories: high copy (tumors with greater than 3 copies of the N-myc or c-myc gene per haploid genome), middle copy (1.5 to 3 copies per genome), and normal copy. Fourteen of the patients had middle copy tumors, but this was almost always a result of chromosome duplication rather than the amplification of a small genetic locus. In contrast, five patients had high copy tumors, with the increased copy number in each case due to gene amplification. The amplification did not occur in a heterogeneous fashion within individual patients, since all metastatic lesions from patients with high copy lung tumors were also high copy, while none of 41 metastatic lesions from the other patients were high copy. These data suggest that gene amplification is an important step in neoplastic growth in a subset of patients with small cell carcinoma of the lung and that this genetic event occurs relatively early (before metastasis) in this subset.     

Antibodies to herpesvirus nonvirion antigens in squamous carcinomas

Serums from tumor-bearing patients, cured patients, and normal subjects were examined for antibodies to the separated complement-fixing reactive components of nonvirion antigens of herpesvirus type 1 and type 2. The occurrence of antibodies to the antigens was similar in serums from tumor-bearing patients and cured patients. Antibodies to the antigens were observed among 21 of 24 (87 percent) cervical cancer cases, 44 of 49 (90 percent) laryngeal cancer cases, 15 of 24 (62 percent) cases of squamous cell carcinomas of the head and neck excluding the larynx, 2 of 24 (8 percent) nonsquamous cell cancer cases, and 3 of 51 (6 percent) normal subjects. By contrast, no differences were found in the titers of neutralizing antibodies to the virus in serums from laryngeal cancer patients and controls. The observations support an etiologic role of herpesviruses in cervical cancer and in laryngeal cancer, and possibly other squamous cell cancers of the head and neck.     

Specific chromosome defect associated with human small-cell lung cancer; deletion 3p(14-23)

A specific, acquired chromosomal abnormality (deletion 3p) has been found in at least one chromosome 3 in 100 percent of the metaphases in 12 of 12 cell lines cultured from human small-cell lung cancer tissue and in 2-day tumor culture specimens from three patients. Analysis of the shortest region of overlap shows the deletion to be 3p(14-23). This specific change was not seen in five of five lung cancer cell lines other than small-cell lung cancer or in two lymphoblastoid lines cultured from cells of small-cell lung cancer patients whose tumors had the 3p deletion.     

Amplification and enhanced expression of the epidermal growth factor receptor gene in A431 human carcinoma cells

The sequence of the human epidermal growth factor (EGF) receptor shows great homology with the avian erythroblastosis virus v-erb B oncogene, raising the possibility that the receptor gene is identical to the c-erb B protooncogene. Human A431 epidermoid carcinoma cells, which have an unusually high number of EGF receptors, were examined to determine whether elevated EGF receptor levels correlate with gene amplification. Southern blots of genomic DNA's from A431 and other human cell lines were probed with either a v-erb B gene fragment or a human EGF receptor complementary DNA clone (pE7), previously isolated from an A431 complementary DNA library. When either probe was used to analyze Eco RI- or Hind III-generated DNA fragments, EGF receptor DNA sequences were amplified about 30-fold in A431. Differences in the banding pattern of A431 DNA fragments relative to normal fibroblast DNA indicate the occurrence of a rearrangement in the region of the receptor gene. Furthermore, A431 cells contain a characteristic, prominent 2.9-kilobase RNA. These results are consistent with the hypothesis that, in A431 cells, gene amplification, possibly associated with a translocation event, may result in the overproduction of EGF receptor protein or the appearance of the transformed phenotype (or both).     

木薯种质资源遗传多态性ISSR分子标记的研究

[目的]研究广西壮族自治区亚热带作物研究所保存的39份木薯种质资源遗传多样性。[方法]筛选出对木薯具有较好多态性和效果的ISSR引物,应用筛选出的引物对39份木薯种质资源进行PCR扩增,并对扩增条带进行统计和分析。同时根据品系间的遗传相似系数,利用UPGMA法进行聚类分析。[结果]筛选出10个ISSR引物,每个引物检测等位基因3～9个,平均为7个,获得70个扩增带形,扩增产物的片段大小范围在150～2 000 bp之间;聚类分析得到,在遗传相似系数0.67上将39个木薯品系分为2个类群,同时聚类分析结果表明,木薯之间的遗传距离基础非常狭窄,遗传相似系数大多在0.80～1.00之间。[结论]为我国优质木薯的育种奠定基础。     

Studies of the HER-2/neu proto-oncogene in human breast and ovarian cancer

Carcinoma of the breast and ovary account for one-third of all cancers occurring in women and together are responsible for approximately one-quarter of cancer-related deaths in females. The HER-2/neu proto-oncogene is amplified in 25 to 30 percent of human primary breast cancers and this alteration is associated with disease behavior. In this report, several similarities were found in the biology of HER-2/neu in breast and ovarian cancer, including a similar incidence of amplification, a direct correlation between amplification and over-expression, evidence of tumors in which overexpression occurs without amplification, and the association between gene alteration and clinical outcome. A comprehensive study of the gene and its products (RNA and protein) was simultaneously performed on a large number of both tumor types. This analysis identified several potential shortcomings of the various methods used to evaluate HER-2/neu in these diseases (Southern, Northern, and Western blots, and immunohistochemistry) and provided information regarding considerations that should be addressed when studying a gene or gene product in human tissue. The data presented further support the concept that the HER-2/neu gene may be involved in the pathogenesis of some human cancers.     

Deleted HTLV-I provirus in blood and cutaneous lesions of patients with mycosis fungoides.

Mycosis fungoides, a rare form of cutaneous T cell leukemia/lymphoma, is suspected of having a viral etiology on the basis of certain similarities to adult T cell leukemia, which is associated with human T cell leukemia/lymphoma virus type I (HTLV-I) infection. Cell lines were established from peripheral blood mononuclear cells (PBMC) of an HTLV-I-seronegative patient with mycosis fungoides. DNA hybridization analysis revealed the presence of HTLV-I-related sequences with unusual restriction endonuclease sites. Sequence analysis of subcloned fragments demonstrated the presence of a monoclonally integrated provirus with a 5.5-kilobase deletion involving large regions of gag and env and all of pol. Additional evidence for the presence of deleted proviruses was found by polymerase chain reaction (PCR) amplification of DNA from cutaneous lesions of five other HTLV-I-seronegative patients. The findings suggest that HTLV-I infection may be involved in the etiology of at least certain cases of mycosis fungoides.     

Amplification and molecular cloning of HTLV-I sequences from DNA of multiple sclerosis patients

Techniques of gene amplification, molecular cloning, and sequence analysis were used to test for the presence of sequences related to human T-lymphotropic virus type I (HTLV-I) in peripheral blood mononuclear cells of six patients with multiple sclerosis (MS) and 20 normal individuals. HTLV-I sequences were detected in all six MS patients and in one individual from the control group by DNA blot analysis and molecular cloning of amplified DNAs. The viral sequence in MS patients were associated with adherent cell populations consisting predominantly of monocytes and macrophages. Molecular cloning and nucleotide sequence analysis indicated that these amplified viral sequences were related to the HTLV-I proviral genome.     

Recombinant origin of the retrovirus XMRV

The retrovirus XMRV (xenotropic murine leukemia virus-related virus) has been detected in human prostate tumors and in blood samples from patients with chronic fatigue syndrome, but these findings have not been replicated. We hypothesized that an understanding of when and how XMRV first arose might help explain the discrepant results. We studied human prostate cancer cell lines CWR22Rv1 and CWR-R1, which produce XMRV virtually identical to the viruses recently found in patient samples, as well as their progenitor human prostate tumor xenograft (CWR22) that had been passaged in mice. We detected XMRV infection in the two cell lines and in the later passage xenografts, but not in the early passages. In particular, we found that the host mice contained two proviruses, PreXMRV-1 and PreXMRV-2, which share 99.92% identity with XMRV over >3.2-kilobase stretches of their genomes. We conclude that XMRV was not present in the original CWR22 tumor but was generated by recombination of two proviruses during tumor passaging in mice. The probability that an identical recombinant was generated independently is negligible (~10(-12)); our results suggest that the association of XMRV with human disease is due to contamination of human samples with virus originating from this recombination event.     

小麦抗叶锈基因Lr37 ISSR分子标记的初步研究

利用ISSR(内部简单重复序列)技术对感病品种Thatcher及20个以Thatcher为轮回亲本的小麦抗叶锈病近等基因系进行分析,找到1个与Lr37基因连锁的ISSR标记。经过多次重复发现,在一套ISSR引物中,引物UBC812在小麦抗叶锈基因Lr37近等基因系间表现多态性。当用这个引物对已知含Lr37基因的3个抗病材料及其它不含Lr37基因的感病材料进行检测时,多态性标记UBC812-1200可以从3个含Lr37基因的抗病材料中检测到1条1200bp的多态性带,而在其它感病材料中均未出现。     

耐草甘膦转EPSPS/GAT大豆多重PCR检测体系的建立及应用

【目的】建立一种精准、高效的草甘膦抗性基因G2-EPSPS和GAT的检测方法,为转基因大豆新品系ZH10-6的广泛应用提供技术支持。【方法】根据抗草甘膦大豆ZH10-6和受体中黄10的分子特征,设计大豆内源参考基因(Actin)、外源基因(G2-EPSPS和GAT)以及侧翼序列(G2EPSPS-2/ZH10P2和ZH10P1/GAT-2)的特异性引物,通过PCR扩增测试引物的特异性和适用性。调整引物配比、DNA模板量、dNTP含量、退火温度和延伸温度等,筛选该多重PCR体系的最适扩增条件。将转基因大豆ZH10-6和受体中黄10的基因组DNA按质量比混合,制备成100%、50%、10%、5%、1%、0.5%、0.1%和0的DNA样品,进行灵敏度检测。运用建立的多重PCR体系检测转基因大豆ZH10-6不同地理来源的11份衍生品系,并根据鉴定结果对该体系的应用性进行评价。【结果】建立的多重PCR方法中引物GmActin11 F/R、G2-EPSPS F/R、GAT F/R、ZH10P1/GAT和G2/ZH10P2可分别扩增出转基因大豆ZH10-6大小为126、430、338、810和1 62...     

Site-specific integration of H-ras in transformed rat embryo cells

A karyotypic analysis was performed on seven independently derived clones of primary rat embryo cells transformed by the ras oncogene plus the cooperating oncogene myc. The transfected oncogenes were sometimes present in amplified copy number, with heterogeneity in the levels of amplification. Some chromosomal features, such as aberrantly banding regions and double-minute chromosomes, typical of cells carrying amplified genes, were also seen in three of the seven cell lines. Underlying this heterogeneity there was an unexpected finding. All seven lines showed a common integration site for ras on the q arm of rat chromosome 3 (3q12), though some lines also had other sites of integration. In four of the lines integration of ras was accompanied by deletion of the p arm of chromosome 3 or its possible translocation to chromosome 12.     

从Raji细胞克隆IL-10基因

[目的]探索一种简便可行的白细胞介素-10(IL-10)基因的克隆方法。[方法]以人Burkitt’s淋巴瘤细胞系Raji细胞为材料,提取培养的Raji细胞中的总RNA。根据GenBank中人IL-10基因序列设计1对特异性引物,用RT-PCR方法扩增人IL-10基因的编码cDNA。回收目的片段,将其与pMD18-T载体连接并转化到大肠杆菌感受态细胞DH5α,构建该基因的重组质粒。重组质粒经PCR和双酶切鉴定后进行测序。[结果]以骨髓细胞组织总RNA为模板进行RT-PCR,可从Raji细胞中获得了预期的约550bp特异性条带。成功构建了IL-10基因的重组质粒,PCR扩增和双酶切的鉴定结果说明该插入片段可能为IL-10cDNA。从获得的阳性克隆中挑选1个菌落来分析重组质粒的插入DNA片段序列。序列分析结果证实其与报道的IL-10基因的序列一致。[结论]该研究为IL-10的重组表达及其生物学活性分析奠定了基础。     

Urinary phenyl acetate: a diagnostic test for depression?

The compound 2-phenylethylamine is an "endogenous amphetamine" which may modulate central adrenergic functions. 2-Phenylethylamine is mainly metabolized by monoamine oxidase to form phenyl acetate (PAA). The 24-hour urinary excretion of PAA was measured in normal healthy volunteers and depressed patients. Patients were diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders, edition 3. In 70 percent of healthy volunteers of both sexes, the excretion of PAA ranged between 70 and 175 milligrams per 24 hours (mean = 141.1 +/- 10.2). Inpatients with major depressive disorder (unipolar type) (N = 31) excreted less PAA (68.7 +/- 7.0 milligrams per 24 hours) and 55 percent of them excreted less than 70 milligrams per 24 hours; there were no significant differences in the PAA excretion between untreated patients (N = 13) and those treated with antidepressants that were not effective (N = 18). The PAA excretion was reduced to a lesser extent in 35 less severely depressed unipolar outpatients (drug-free for 1 week) (86.3 +/- 11.8 milligrams per 24 hours). These results suggest that low PAA urinary excretion may be a reliable state marker for the diagnosis of some forms of unipolar major depressive disorders.     

铁观音及黄棪半同胞系种质遗传多样性的ISSR分析

铁观音和黄棪是乌龙茶茶树育种的骨干亲本,以这2份品种及其为亲本选育出的新种质及不同地域种质的铁观音茶树为研究材料,采用ISSR分子标记技术,利用筛选出的9个多态性较好、扩增条带较清晰的ISSR引物,分别对24份茶树品种(系)进行扩增,分析其遗传多样性和亲缘关系。结果表明:9个ISSR引物共扩增出73条稳定的谱带,其中47条具有多态性,多态性比率为64.4%,平均每个引物扩增出5.2条谱带;遗传相似性分析显示24份供试种质的遗传相似系数0.544~0.889,平均为0.727,表明供试种质的遗传基础较窄,亲缘关系较近。     

High efficiency DNA-mediated transformation of primate cells

Tissue culture cells from several mammalian species, including three primate lines, were transfected with recombinant vectors carrying Escherichia coli xanthine-guanine phosphoribosyltransferase or Tn5 aminoglycoside phosphotransferase dominant selectable markers. Human HeLa and SV40-transformed xeroderma pigmentosum cells exhibited stable transformation frequencies of at least 10(-3) (0.1 percent). CV-1, an African green monkey kidney cell line, could be stably transformed with the exceptionally high frequency of 6 X 10(-2) (6 percent).