启动子对外源基因在转基因植物中表达的影响

将来自ｐＢＩ１２１质粒的ＣａＭＶ３５Ｓ启动子片段插入到ｐＢＩ１２１的ＣａＭＶ３５Ｓ启动子与ＧＵＳ基因之间，构建了串联的ＣａＭＶ３５Ｓ启动子载体ｐＬＢ３８．通过三亲交配，将ｐＢＩ１２１及ｐＬＢ３８分别转移到含ｐＧｖ３８５０的农杆菌中，成为适合本研究的双元载体。以叶圆盘转化法将外源基因转入烟草，获得了２种转基因植株。经ＤＮＡ分子杂交、ＮＰＴⅡ点分析、ＧＵＳ荧光定性及定量分析，证明外源基因已整合进烟草基因组并获得表达。ｐＬＢ３８的ＧＵＳ表达量为ｎＢｌ１２１的３～４倍，这表明启动子数目的不同会直接影响其启动基因的表达水平。     

Neurofilament proteins in neurodegenerative diseases

The function of neurofilaments, the major component in large myelinated neurons, is not well understood even though they were discovered as structures over 100 years ago. Recent studies have suggested that neuro-filaments are closely related to many neurodegenerative diseases, such as amyotrophic lateral sclerosis, Parkinson disease Alzheimer disease, and diabetes. Using in vitro assays, cultures and transgenic mice, these studies provided new insights into neurofilament function. The function of each subunit, the relationship of neurofilaments with other cytoskeletal elements and their clinical significance are topics of increasing attention.Received 22 June 2004; received after revision 4 August 2004; accepted 19 August 2004     

Isolation and ectopic expression of a bamboo MADS-box gene

A cDNA named DIMADS18 was isolated from the young spikelets of the sweet bamboo, Dendrocalamus latiflorus by RACE. DNA sequence analysis showed that DIMADS18 was composed of full ORF and 3UTR, but without 5UTR. The cDNA contained 1039 nucleotides and encoded a putative protein of 249 amino acid residues. The gene displayed the structure of a typical plant MADS box gene, which consisted of an MADS domain, K domain, a short I region, and the C-terminal region. Phylogenetic analysis of plant MADS box genes based on amino acid sequences revealed that DlMADS18 was grouped into the AGAMOUS-LIKE 6 (AGL6)-like subfamily. It was most likely homologous to the OsMADS6 of rice (Oryza sativa), with 88% sequence identity for the entire amino acid sequences. The DlMADS18 also showed relatively high amino acid sequence identity (59%) to AGL6 ofArabidopsis thaliana. To study the functions of DlMADS18, DlMADS18 cDNA clone driven by the CaMV 35S promoter was transformed into Arabidopsis plants. Transgenic plants of DlMADS18 exhibited the phenotypes of curled leaves, dwarfism, and early flowering with clustered terminal flowers. These results indicated that DlMADS18 may probably be involved in controlling the flowering time of D.latiflorus.     

抗冻蛋白-GUS基因诱导性融合表达载体转化烟草植株中GUS活性测定

把修饰合成的带有甘薯信号肽序列的抗冻蛋白成串基因与β-葡萄糖醛酸苷酶(GU S)报道基因融合克隆在大豆热休克启动区下游构建了温度诱导型双元载体pBF 04,三亲株配对法转化根癌农杆菌,叶盘法导入烟草,获得了转基因烟草植株.将10株转基因烟草放置在40℃诱导不同时间,利用荧光光度分析法测定水解液中GU S活性,结果诱导18、24、48小时的4株中GU S活性明显高于对照组和诱导6、12小时组,说明我们修饰合成的抗冻蛋白与GU S基因融合构建的载体在热休克启动区控制下可以诱导表达.经组织化学法测定这些阳性植株的叶片和茎段切片细胞间隙显示GU S活性,提示甘薯信号肽可能起作用.     

Transgene for growth hormone in common carp（Cyprinus carpio L.） promotes thymus development

The transgenic carp were produced by micro-injection of CAgcGHc into the fertilized eggs. Observation of the thymus development between the transgenics and non- transgenic controls was carried out. The thymus of one-year- old transgenics F1 showed a great increase in both size and weight. The unilateral thymus of the transgenics weighed from 190 to 295 mg with average 218.6 mg, whereas the uni-lateral thymus of the controls weighed 20—81 mg with av-erage 42.5 mg; i.e. the thymus weight in the transgenics was 5.14 fold over that in the controls. The index of thymus/body weight in the transgenics was 2.97 fold over the controls. Light microscopy observation indicated that the thymus of the transgenics well developed with the thickened outer re-gion and compactly arranged thymocytes, while the thymus in the controls were degenerating with the thinned outer region, scattered thymocytes and groups of fatty cells. Fur-ther analysis with the electron microscopy revealed that pro-liferous cells in the transgenics were mainly small lympho-cytes and no pathological changes were found. The results confirmed that the 揂ll-fish?GH-transgene promotes thy-mus development and thymocyte proliferation, and retards thymus degeneration. The study has laid a foundation for further analysis of the immunobiological function in GH- transgenic carp.     

Transgenic and knock-out mice for deciphering the roles of EGFR ligands

Generation of genetically engineered mice with either gain-of-function or loss-of-function mutations is the most popular technique for determining gene functions and the interrelationship between molecules in vivo. These models have provided a wealth of information about the developmental and physiological roles of oncogenes and growth factors. To date, transgenic techniques have been used extensively to study the functions of the epidermal growth factor (EGF) family. This review highlights some of the major recent findings pertinent to the EGF receptor (EGFR) and its ligands with special reference to elucidating how EGF and its related growth factors work together to regulate reproduction, growth and development. Finally, future investigations on ligand-ligand communications, EGFR and its ligands in neural stem cell research, and the mechanisms of EGFR signaling and trafficking in cells are also suggested. Received 24 May 2002; received after revision 15 July 2002; accepted 16 July 2002     

Expression of biologically active human clotting factor IX (hF IX) in the mammary gland of transgenic mice

The DNA of human factor IX (hF IX) gene vector pMC IX m, which had been proven to be able to express inin vitro and living cells, was introduced into 586 zygotes of Kunming Whlte Mice by positive pressure microinjection technique with manual operation. The 499 survival embryos after microinjection were then transferred into pseudopregnant recipient mice and 216 F, pups were born. The analysis of PCR and Southern blot hybridization showed that, of the 216, 6 (2 females and 4 males) were integrated with foreign DNA in their genornes, giving an integration frequency of 3% (6/216). Two F₀ female transgenic mice could express hF IX protein in their milk and the content was over 100 ng/mL as measured with ELISA. The biological activities of hF IV in the milk of two F₀ mike were 44.67 % and 79.43 %, respectively.     

外源基因在转基因动物乳腺中的特异性表达研究

动物基因工程研究最大的突破就是转基因动物研究的进展,自八十年代初第一批转基因小鼠问世以来,转基因动物的研究已从方法学研究步入了应用性研究阶段,转基因动物除作为研究工具广泛应用于发育生物学、免疫学、遗传学以及医学等生命科学领域外,外源基因在转基因动物的特异性表达,尤其是在乳腺的表达,又可将转基因用作生物反应器进行了生物活性蛋白的生产而于商业生产,在转基因动物乳腺的特异性表达研究中,寻找乳蛋白基因调控