转基因植物蛋白有助于治疗自身免疫性疾病

据伦敦的研究人员报道,转基因植物有可能成为治疗各种自身免疫性疾病的蛋白质来源。对自身免疫性疾病和排异反应来说,有些植物甚至可被用作可食用治疗方法。更重要的是能对一些植物进行设计,因此,这些植物产生的蛋白质非常贵重,而从其他途径尤其难以得到。伦敦卫生科学中心移植和免疫生物学组的肾病学家Anthony Tevnikar目前正与农业方面的研究人员进行合作。

Increasing Accumulation Level of Foreign Protein in Transgenic Plants Through Protein Targeting

Targeting of the synthesized polypeptide in the cells is an important research field in modern cell biology. Cowpea trypsin inhibitor (cpti) gene has been modified and a fusion protein gene (sck) was produced by fusing a signal peptide sequence at cpti 5' end and an endoplasm reticulum (ER) retention signal peptide at cpti3' end respectively. The signal peptide can direct the newly synthesized polypeptide into ER, while ER retention signal can make the protein retained in the ER and its derivative protein body. ELISA test indicated that the accumulation level of foreign CpTI protein in sck transgenic tobacco (Nicotiana tabacum L.) was two times higher than cpti transgenic tobaccos and some individuals were four times higher. At the same time, sck transgenic tobacco has a high resistance to Lepidoptera pest due to the increased accumulation level of foreign CpTI protein. The strategy of foreign protein targeting can be used to increase the accumulation level of foreign protein in transgenic plants and can be widely applied to other related research field in plant genetic engineering.

Virus Movement Protein Gene Mediated Resistance Against Cucumber Mosaic Virus Infection

Tobacco ( Nicotiana tabacum L.) “NC89” plants were transformed with deletion mutant of cucumber mosaic virus (CMV) movement protein (MP) gene and full_length CMV MP gene, respectively. The transformed plants were analyzed with polymerase chain reaction (PCR), PCR_Southern, Southern and Western blots. R 0 generation of the transgenic plants were inoculated with CMV. Five out of 10 lines of tobacco plants (BMPK) transformed with CMV MP deletion mutant gene showed high resistance to CMV infection and remained symptomless for up to 50 days post_inoculation. In contrast, tobacco plants (BMPR) transformed with full_length CMV MP gene did not show resistance to CMV infection. However, most of the infected full_length CMV MP gene transgenic plants recovered by showing none or very mild mosaic symptoms in 40 days post_inoculation. The results of R 1 generation of the BMPK transgenic plants tested under field conditions showed that all 5 lines of transgenic plants could delay the virus disease development.

Application of GFP Gene in the Study of Insect-Resistant Transgenic Plants

用合成的cry1Ac基因与绿色荧光蛋白基因 (GFP)构成融合蛋白基因 ,然后和改造的GNA基因构建双价抗虫基因植物表达载体pBGbfg ,经根癌农杆菌介导转化了烟草。在紫外灯照射下 ,观察到转基因植株叶片中有较强的绿色荧光 ;经抗虫试验、PCR、Southernblot和Westernblot等检测 ,表明该重组植物表达载体能够在转基因植物中有效表达外源基因 ,转基因植株绿色荧光的表型与其抗虫性密切相关。从而成功地建立了以绿色荧光蛋白基因与抗虫基因组成的融合基因转化系统 ,简化了抗虫转基因植物筛选程序 ,有助于快速获得双价抗虫转基因植株。

The Expression and Functional Analysis of the Gene At2G34450 in High Mobility Group B Proteins from Arabidopsis thaliana

[Objective]To better understand the functions of High Mobility Group B （HMGB） proteins in the transcriptional regulation of plant stress responses.[Method]We cloned the At2G33450 gene encoding At2G34450 protein in Arabidopsis thaliana.Binary vectors carrying the above gene were transformed into Arabidopsis to detect the influences of environmental stimuli to transgenic Arabidopsis.[Result] Under salt or drought stress the transgenic Arabidopsis plants over-expressed At2G33450 displayed retarded germination and subsequent growth compared with wild-type plants.[Conclusion]Our results provide a novel basis for understanding the biological functions of HMGB protein family members that differently affect germination and seedling growth of Arabidopsis plants under various stress conditions.

Techniques for Detecting Functional Protein Expression in Transgenic Plants

With the development of plant genetic engineering techniques, numerous genetically modified plants have been generated. At the same time, the technologies for detecting transgenic organisms get improved constantly, which also promotes the scientific identification, evaluation and commercial cultivation of transgenic plants. In this review, we evaluate various detection methods for transgenic plants at the level of protein expression.

Isolation and functional analysis of a Brassica juncea gene encoding a com-ponent of auxin efflux carrier

Polar auxin transport plays a divergent role in plant growth and developmental processes including root and embryo development, vascular pattern formation and cell elongation. Recently isolated Arabidopsis pin gene family was believed to encode a component of auxin efflux carrier (G(?)lweiler et al, 1998). Based on the Arabidopsis pin1 sequence we have isolated a Brassica juncea cDNA (designated Bjpin1), which encoded a 70-kDa putative auxin efflux carrier. Deduced BjPIN1 shared 65% identities at protein level with AtPINl and was highly homologous to other putative PIN proteins of Arabidopsis (with highest homology to AtPIN3). Hydrophobic analysis showed similar structures between BjPINl and AtPIN proteins. Presence of 6 exons (varying in size between 65 bp and 1229 bp) and 5 introns (sizes between 89 bp and 463 bp) in the genomic fragment was revealed by comparing the genomic and cDNA sequences. Northern blot analysis indicated that Bjpin1 was expressed in most of the tissues tested, with a relatively higher level of transcript in flowers and a lower level in root tissues. Promoter-reporter gene fusion studies further revealed the expression of Bjpin1 in the mature pollen grains, young seeds, root tip, leaf vascular tissue and trace bundle, stem epidermis, cortex and vascular cells. BjPINl was localized on the plasma membrane as demonstrated through fusion expression of green fluorescent protein (GFP). Auxin efflux carrier activity was elevated in transgenic Arabidopsis expressing BjPIN1.

TRANSGENIC PLANTS EXPRESSING BACILLUS THURINGIENSIS DELTA-ENDOTOXINS

Commercial varieties of transgenic Bacillus thuringiensis (Bt) plants have been developed in many countries to control target pests. Initially, the expression of native Bt genes in plants was low due to mRNA instability, improper splicing, and post translation modifications. Subsequently, modifications of the native Bt genes greatly enhanced expression levels. This is a review of the developments that made modern high expression transgenic Bt plants possible, with an emphasis on the reasons for the low level expression of native Bt genes in plant systems, and the techniques that have been used to improve plant expression of Bt toxin genes.