A new class of endogenous human retroviral genomes

Human DNA contains multiple copies of a novel class of endogenous retroviral genomes. Analysis of a human recombinant DNA clone (HLM-2) containing one such proviral genome revealed that it is a mosaic of retroviral-related sequences with the organization and length of known endogenous retroviral genomes. The HLM-2 long terminal repeat hybridized with the long terminal repeat of the squirrel monkey virus, a type D retrovirus. The HLM-2 gag and pol genes share extensive nucleotide sequence homology with those of the M432 retrovirus (a type A-related retrovirus), mouse mammary tumor virus (a type B retrovirus), and the avian Rous sarcoma virus (a type C retrovirus). Nucleotide sequence analysis revealed regions in the HLM-2 pol gene that were as much as 70 percent identical to the mouse mammary tumor virus pol gene. A portion of the putative HLM-2 env gene hybridized with the corresponding region of the M432 viral genome.     

High levels of intracellular bombesin characterize human small-cell lung carcinoma

"Small cells" or "oat cells" characterize a virulent form of lung cancer and share many biochemical properties with peptide-secreting neurones. The neuropeptide bombesin is present in all small-cell lines examined, but not in other lung cancer cell lines, suggesting that bombesinergic precursor cells in lung may give rise to this disease.     

基于两个核基因序列研究龟鳖类的系统进化特征

为从核基因的角度探讨龟鳖类的系统发育特征,采用PCR扩增和测序的方法,获得两种龟的R35内含子部分序列以及6种龟的RAG2基因部分序列,结合NCBI其它龟鳖的同源序列一并进行分析。结果表明：将R35序列比对后得到941 bp的一致序列,将RAG2比对后得到620 bp的一致序列,二者合并后,比对排序后得到1561 bp的一致序列,其中共有505个可变核苷酸位点,总变异率为32.35%;简约信息位点为239个,插入/缺失为139个,转换/颠换比率为1.64。碱基A、T、G、C的平均含量分别为29.5%、28.5%、22.8%、19.2%。海龟科和鳄龟科之间Kimura双参数（K-2-P）遗传距离最小（0.025）,鳖科和南美侧颈龟科之间的遗传距离最大（0.182）。分子系统树结果显示：1）陆龟科与潮龟科先聚在一起,再与龟科聚在一起,陆龟科与潮龟科构成一个单系类群;2）支持陆龟总科与鳄龟科＋海龟总科构成姐妹群;3）鳄龟科和海龟总科是姐妹群的关系。     

基于两个核基因序列研究龟鳖类的系统进化特征

为从核基因的角度探讨龟鳖类的系统发育特征,采用PCR扩增和测序的方法,获得两种龟的R35内含子部分序列以及6种龟的RAG2基因部分序列,结合NCBI其它龟鳖的同源序列一并进行分析。结果表明:将R35序列比对后得到941 bp的一致序列,将RAG2比对后得到620 bp的一致序列,二者合并后,比对排序后得到1561 bp的一致序列,其中共有505个可变核苷酸位点,总变异率为32.35%;简约信息位点为239个,插入/缺失为139个,转换/颠换比率为1.64。碱基A、T、G、C的平均含量分别为29.5%、28.5%、22.8%、19.2%。海龟科和鳄龟科之间Kimura双参数(K-2-P)遗传距离最小(0.025),鳖科和南美侧颈龟科之间的遗传距离最大(0.182)。分子系统树结果显示:1)陆龟科与潮龟科先聚在一起,再与龟科聚在一起,陆龟科与潮龟科构成一个单系类群;2)支持陆龟总科与鳄龟科+海龟总科构成姐妹群;3)鳄龟科和海龟总科是姐妹群的关系。     

2种杨树嫩茎质外体内源激素对盐胁迫的响应

以春季盆栽的‘吴屯杨’与‘荷兰杨’为试验材料,采用微透析技术,结合高效液相色谱测定不同浓度NaCl(0、200、300mmol/L)胁迫下2种杨树嫩茎质外体的内源激素变化.结果表明:盐胁迫下2种杨树嫩茎质外体内脱落酸(ABA)含量升高,其他激素含量降低;高浓度盐胁迫下脱落酸(ABA)的积累量大于中浓度盐胁迫;同等盐胁迫条件下,‘荷兰杨’需要积累较‘吴屯杨’更多的脱落酸(ABA)来抵御胁迫环境;‘吴屯杨’的抗盐平衡系数小于‘荷兰杨’;2种杨树的细胞分裂素(CTK)与吲哚乙酸(IAA),细胞分裂素(CTK)与赤霉素(GA),吲哚乙酸(IAA)与赤霉素(GA)显著相关;‘吴屯杨’的耐盐性强于‘荷兰杨’.     

Isolation of human transcribed sequences from human-rodent somatic cell hybrids

A method was developed for selectively isolating genes from localized regions of the human genome that are contained in interspecific hybrid cells. Complementary human DNA was prepared from a human-rodent somatic cell hybrid that contained less than 1% human DNA, by using consensus 5' intron splice sequences as primers. These primers would select immature, unspliced messenger RNA (still retaining species-specific repeat sequences) as templates. Screening a derived complementary DNA library for human repeat sequences resulted in the isolation of human clones at the anticipated frequency with characteristics expected of exons of transcribed human genes--single copy sequences that hybridized to discrete bands on Northern (RNA) blots.     

Global identification of human transcribed sequences with genome tiling arrays

Elucidating the transcribed regions of the genome constitutes a fundamental aspect of human biology, yet this remains an outstanding problem. To comprehensively identify coding sequences, we constructed a series of high-density oligonucleotide tiling arrays representing sense and antisense strands of the entire nonrepetitive sequence of the human genome. Transcribed sequences were located across the genome via hybridization to complementary DNA samples, reverse-transcribed from polyadenylated RNA obtained from human liver tissue. In addition to identifying many known and predicted genes, we found 10,595 transcribed sequences not detected by other methods. A large fraction of these are located in intergenic regions distal from previously annotated genes and exhibit significant homology to other mammalian proteins.     

Nucleotide sequences of the human and mouse atrial natriuretic factor genes

Mouse and human atrial natriuretic factor (ANF) genes have been cloned and their nucleotide sequences determined. Each ANF gene consists of three coding blocks separated by two intervening sequences. The 5' flanking sequences and those encoding proANF are highly conserved between the two species, while the intervening sequences and 3' untranslated regions are not. The conserved sequences 5' of the gene may play an important role in the regulation of ANF gene expression.     

Complete nucleotide sequences of two isolates of Cherry virus A from sweet cherry in China

Cherry virus A(CVA) is a member of the genus Capillovirus, in the family Betaflexiviridae. The infection rate of CVA was high in sweet cherry in China. We determined the complete nucleotide sequences of two isolates of CVA from Tai'an, Shandong Province, China using high fidelity PCR enzymes and specific primer pairs for amplifying long fragments in RT-PCR and RACE. The full-length sequences from isolates Ch TA11 and Ch TA12 are both 7 382 nucleotide(nt) long, excluding the poly(A) tail, encode two open reading frames(ORFs) and have similar genome organization to the two isolates in GenBank. The complete nucleotide sequence of Ch TA11 is 98.2 and 81.2% nt identity to t he isolates from Germany and India in Gen Bank, respectively, and the Ch TA12 isolate is 98.2 and 81.0% similar. Analysis of the nucleotide and amino acid sequences showed that the domain of unknown function(DUF1717) is more variable compared with other domains. This is the first report of the complete nucleotide sequences of CVA isolates infecting sweet cherry in China.     

携带人血清白蛋白cDNA的逆转录病毒质粒载体的构建

采用粘平端定向基因克隆技术,成功地构建了携带ＨＳＡｃＤＮＡ基因片段的重组逆转录病毒质粒载体ＧＩＮＨＳＡａ。经限制性酶切鉴定和菌落原位杂交证明ＨＳＡｃＤＮＡ已克隆到Ｇ１Ｎａ当中并得到９个重组病毒质粒载体阳性克隆。     

Phylogenetic shadowing of primate sequences to find functional regions of the human genome

Nonhuman primates represent the most relevant model organisms to understand the biology of Homo sapiens. The recent divergence and associated overall sequence conservation between individual members of this taxon have nonetheless largely precluded the use of primates in comparative sequence studies. We used sequence comparisons of an extensive set of Old World and New World monkeys and hominoids to identify functional regions in the human genome. Analysis of these data enabled the discovery of primate-specific gene regulatory elements and the demarcation of the exons of multiple genes. Much of the information content of the comprehensive primate sequence comparisons could be captured with a small subset of phylogenetically close primates. These results demonstrate the utility of intraprimate sequence comparisons to discover common mammalian as well as primate-specific functional elements in the human genome, which are unattainable through the evaluation of more evolutionarily distant species.     

Isolation of human oncogene sequences (v-fes homolog) from a cosmid library

To define the human homolog (or homologs) of transforming sequences (v-fes gene) common to Gardner (GA) and Snyder Theilen (ST) isolates of feline sarcoma virus (FeSV), a representative library of human lung carcinoma DNA in a cosmid vector system was constructed. Three cosmid clones were isolated containing GA/ST FeSV v-fes homologous cellular sequences, within 32- to 42-kilobase cellular inserts representing 56 kilobases of contiguous human cellular DNA. Sequences both homologous to, and colinear with, GA or ST FeSV v-fes are distributed discontinuously over a region of up to 9.5 kilobases and contain a minimum of three regions of nonhomology representing probable introns. A thymidine kinase selection system was used to show that, upon transfection to RAT-2 cells, the human c-fes sequence lacked detectable transforming activity.     

Comment on "The consensus coding sequences of human breast and colorectal cancers"

Sj?blom et al. (Research Article, 13 October 2006, p. 268) reported nearly 200 novel cancer genes said to have a 90% probability of being involved in colon or breast cancer. However, their analysis raises two statistical concerns. When these concerns are addressed, few genes with significantly elevated mutation rates remain. Although the biological methodology in Sj?blom et al. is sound, more samples are needed to achieve sufficient power.     

人溶菌酶活性两种检测方法的比较研究

为了比较琼脂平板扩散法和RBB-R染料标记比色法测定溶菌酶活性的灵敏度和可重复性,分别以人溶菌酶标准品建立标准曲线,用两种方法对不同稀释倍数的人溶菌酶进行5次重复测定,并分析测定结果的标准差、变异系数和误差率。结果表明:两种方法测定溶菌酶的灵敏度分别为1.5和0.5μg·mL-1,RBB-R染料法标准差、变异系数、误差率均小于琼脂平板扩散法。用RBB-R染料标记比色法测定的正常鸡蛋清中溶菌酶含量为2.84-4.19mg·mL-1,与报道的相符,说明RBB-R染料标记比色法具有操作简便、定量准确和重复性好等优点,适合大批样品及微量样品的检测。     

两个菊花品种扦插生根过程及其插穗碳氮营养和内源激素的变化

以2个扦插生根能力不同的菊花品种雨花星辰和天坠玉露为材料,测定了扦插过程中叶片和茎的碳氮营养含量变化和插穗皮部内源激素IAA、ABA、GA3和iPA含量的变化.结果表明:通过形态解剖观察,雨花星辰和天坠玉露根原基形成时间不同,分别在扦插6 d和14 d后观察到根原基原始细胞,并于12 d和20 d后开始生根.扦插生根前2个品种叶片和茎的碳水化合物含量总体呈现先下降后上升的趋势,生根后再度下降,而氮素含量呈较稳定的下降趋势;2个品种相比,易生根品种插穗有较高的糖/氮;扦插过程中,光合产物优先在茎积累,C/N在茎中先回升,生根后茎中C/N显著高于叶片.扦插生根过程中,内源激素含量也存在显著变化:IAA和ABA含量在根原基形成期均出现上升,但生根过程中IAA/ABA变化不显著,易生根品种IAA/ABA较高;扦插过程GA3/ABA先上升后在根原基形成期下降,iPA含量在整个生根过程中不断下降引起IAA/iPA上升.提示:碳水化合物代谢及生根部位内源激素变化与生根过程密切相关.     

5' viral and human cellular sequences corresponding to the transforming gene of simian sarcoma virus

The 5' nucleotide sequences of the transforming gene of simian sarcoma virus (v-sis) and its human cellular homolog (c-sis) were compared. A short homology was found between helper virus and cellular DNA sequences at the junction of v-sis and c-sis, which may have had a role in the original recombination event leading to the generation of simian sarcoma virus.     

Novel viral sequences related to human T-cell leukemia virus in T cells of a seropositive baboon

Antibodies reactive with proteins of human T-cell leukemia virus (HTLV) can be found in Old World monkeys. A T-lymphocyte cell line established from a seropositive baboon (Papio cynocephalus) was analyzed for the presence of viral DNA sequences. The provirus found in these cells was related to but distinct from HTLV subgroup I. These results add to recent evidence from human studies that HTLV represents a spectrum of infectious T-lymphotropic retroviruses that includes closely and distantly related members.