Epigallocatechin-3-gallate treatment to promote neuroprotection and functional recovery after nervous system injury

Traumatic spinal cord injury （SCI） causes motor paralysis, sensory anesthesia and autonomic dysfunction below the le- sion site and additionally some SCI patients refer neuropathic pain together with these signs and symptoms. Clinical and experimental studies have revealed the main pathological changes of injured spinal cord implicated in all these signs and symptoms, including neuropathic pain. After few hours of traumatic SCI, it is usual to observe broken blood brain barrier with plasma and blood cells extravasation, cell necrosis, disruption of ascending and descending spinal cord pathways and increased potassium and glutamate. Glutamate contributes to excitotoxicity of neurons whereas potassium facilitates ectopic depolarization of survival neurons and activation of resident microglia.

Transcription Activity of Ectogenic Human Carcinoembryonic Antigen Promoter in Lung Adenocarcinoma Cells A549

The transcription activity of ectogenic human carcinoembryonic antigen （CEA） promoter in lung adenocarcinoma cells A549 was investigated for the further gene-targeting therapy. The reporter gene green fluorescent protein （GFP） driven by CEA promoter and human cytomegalovirus （CMV） promoter were relatively constructed and named plasmid pCEA-EGFP and pCMV-GFP respectively. The intensity of fluorescence was detected by fluorescence microscope and flow cytometry analysis after the pCEA-GFP and pSNAV-GFP plasmids were transfected into A549 cells through liposome respectively. The results showed （4,08±0.63） % of the A549 cells transfected with pCEA-AFP plasmid expressed, significantly lower than that of the A549 cells transfected with pCMV-GFP [（43.27±3.54） %]. It was suggested that ectogenic human CEA promoter in lung adenocarcinoma cells A549 was weakly expressed. The distinct specificity of CEA promoter in CEA high expression cells was regarded as a tool in selective gene therapy, but the transcription activity of ectogenic human CEA promoter was needed to increase in the future.

The choline pathway as a strategy to promote central nervous system(CNS) remyelination

Multiple sclerosis is a chronic companied by demyelination inflammatory disease that is ac- and axonal damage resulting in neurological deficits. Remyelination is the natural endogenous repair mechanism of demyelinated axons and it is supposed to protect axons/neurons from degeneration and thus the patient from progressive disability （Franklin and Ffrench-Constant, 2008）. Current therapeutics for patients with multiple sclerosis are to some extent very effective in inhibiting neuroinflamma- tion and demyelination. However, to date there are no substanc- es available that can enhance remyelination. Remyelination is the result of recruitment/proliferation of new oligodendrocyte precursor cells （OPC） and differentiation into mature myelin producing oligodendrocytes （Franklin and Ffrench-Constant, 2008）. These processes are supported by many factors and signals and failure at any stage might lead to repair failure. Strategies to enhance myelin repair are either the promotion of endogenous repair mechanisms via modulation of OPC prolif- eration and oligodendrocyte differentiation or the transplantion of myelinating cells into lesions. Due to the multiloculated pro- cess in multiple sclerosis and the ethical problems with the cell source, the latter is less favoured. The endogenous promotion of remvelination could be achieved by several approaches such as：

Isolation of a pollen-specific promoter in tritordeum

The promoter is a cis-acting element in regulating gene expression. A promoterless plasmid containing UidA gene was transformed into tritordeum by barmbadment. Histochemical analysis of various tissues in transgenic tritordeum was carried to examine tissue-specific expression of GUS(beta-glucuronidase) activity. The pollen-specific promoter was trapped and identified successfully in a transformant line. PCR(polymerase chain reaction) method was used to isolate this pollen-specific promoter. By sequencing and analyzing the amplified fragment from PCR, a part of UidA gene and a flanking sequence were obtained. Some essential elements of plant promoters were found in the sequence. To determine the function of it, the cloned fragment was fused with UidA gene, then cloned and transformed into Triticum durum. The transgenic plant transformed by this vector showed GUS expression only in pollen. Therefore a pollen-specific promoter was isolated successfully.

Analysis of Wheat GBSS1 Promoter:Tissue Specificity and DNA Methylation

The cis-regulatory elements of promoters regulate temporal and spatial expression of genes. DNA inethylation, histone methylation and histone acetylation are the main types of epigenetic modifications, which play important roles in plant growth and development. DNA methylation could seilenco transposons, affect gene imprinting and gene expression. In this study, we found that granule bound starch synthase 1 （GBSSI） gene is expressed specifically in wheat endosperm rath- er than in the embryo. We also analyzed the cis-elements within this promoter region and found some seed-specific elements. In order to confirm the tissue specifici- ty, we cloned 4k bp sequences upstream of GBSS1 gene to link to vector with GUS and this construct was transferred to tobacco by Agrobacterium mediated transfor- marion. The results showed that wheat GBSS1 promoter mediated the seed-specific expression of GUS gene, hut not mediated expression in embryo. In addition, we found that GBSSI promoter is methylated in wheat embryo and de-methylated in wheat endosperm. Our study might provide the molecular basis for specific expres- sion of GBSSI gene.

Rice tissue-specific promoters and conditiondependent promoters for effective translational application

Rice （Oryza sativa） is one of the most important staple food crops for more than half of the world＇s population. The demand is increasing for food security because of population growth and environmental challenges triggered by climate changes. This scenario has led to more interest in developing crops with greater productivity and sustainability. The process of genetic transformation, a major tool for crop improvement, utilizes promoters as one of its key elements. Those promoters are generally divided into three types： constitutive, spatiotemporal, and condition-dependent. Tran- scriptional control of a constitutive promoter often leads to reduced plant growth, due to a negative effect of accumu- lated molecules during cellular functions or energy consump- tion. To maximize the effect of a transgene on transgenic plants, it is better to use condition-dependent or tissue- specific promoters. However, until now, those types have not been as widely applied in crop biotechnology. In this review, we introduce and discuss four groups of tissue-specific promoters （5o promoters in total） and six groups of condition-dependent promoters （27 promoters）. These pro- moters can be utilized to fine-tune desirable agronomic traits and develop crops with tolerance to various stresses, enhanced nutritional value, and advanced productivity.

Transgenic Bt cotton driven by the green tissue-specific promoter shows strong toxicity to lepidopteran pests and lower Bt toxin accumulation in seeds

A promoter of the PNZIP （Pharbitis nil leucine zipper） gene （1.459 kb） was cloned from Pharbitis nil and fused to the GUS（^-glucuronidase） and Bacillus thuringiensis endotoxin （Cry9C） genes. Several transgenic PNZIP：：GUS and PNZIP：：Cry9C cotton lines were developed by Agrobacterium-mediated transformation. Strong GUS staining was detected in the green tissues of the transgenic PNZIP：：GUS cotton plants. In contrast, GUS staining in the reproductive structures such as petals, anther, and immature seeds of PNZIP：：GUS cotton was very faint. Two transgenic PNZIP：：Cry9C lines and one trans- genic cauliflower mosaic virus （CaMV） 35S：：Cry9C line were selected for enzyme-linked immunosorbent assay （ELISA） and insect bioassays. Expression of the Cry9C protein in the 35S：：Cry9C line maintained a high level in most tissues ranging from 24.6 to 45.5 ~tg g-I fresh weight. In green tissues such as the leaves, boll rinds, and bracts of the PNZIP：：Cry9C line, the Cry9C protein accumulated up to 50.2, 39.7, and 48.3 jag g-a fresh weight respectively. In contrast, seeds of the PNZIP：：Cry9C line （PZ1.3） accumulated only 0.26 ~ag g-~ fresh weight of the Cry9C protein, which was 100 times lower than that recorded for the seeds of the CaMV 35S：：Cry9C line. The insect bioassay showed that the transgenic PNZIP：：Cry9C cotton plant exhibited strong resistance to both the cotton bollworm and the pink bollworm. The PNZIP promoter could effectively drive Bt toxin ex- pression in green tissues of cotton and lower accumulated levels of the Bt protein in seeds. These features should allay public concerns about the safety of transgenic foods. We propose the future utility of PNZIP as an economical, environmentally friendly promoter in cotton biotechnology.

Isolation and functional analysis of a strong specific promoter in photosynthetic tissues

PNZIP gene promoter has been cloned from Pharbitis nil by adaptor PCR, which con-forms to eukaryotic promoter characteristic. Primer extension analysis showed that the transcrip-tion start site was located 122 nucleotides upstream of the translation start site of PNZIP gene. According to the characteristic of PNZIP promoter, a series of deletions were purposely made by PCR. Five deletion fragments were fused to upstream of GUS gene and transferred into tobacco. Fluorometric GUS assay showed that five different length promoters all could specifically drive GUS gene expression in photosynthetic tissues and their activities decreased along with the gradual deletion of PNZIP promoter. In addition, the activity of full-length promoter was 9 times higher than that of CaMV 35S in leaf. PNZIP promoter may have two putative cis-elements, GAAATA and GATACT, which relate to gene expression in photosynthetic tissues. GATACT may determine the gene specific expression in photosynthetic tissues, while GAAATA, perhaps, as an enhancer, increases the intensity of gene expression.

Structural and functional analysis of an asymmetric bidirectional promoter in Arabidopsis thaliana

Bidirectional promoters are relatively abundant in eukaryotic genomes, suggesting that they have an important biological significance. As yet, few of these promoters have been characterized in detail. Here, using a promoter：：GUS transgene approach has revealed that the intergenic region of Arabidopsis thaliana divergent genes At1g71850 and At1g71860 is an asymmetric bidirectional promoter, which exhibits an orientation-dependent expression profile. The strength of the forward promoter was greater than that of the reverse promoter, and their tissue specificities were not identical. Deletion analyses revealed that this bidirectional promoter could be divided into three functional regions. The basal level and tissue specificity of the promoter in the reverse orientation were regulated positively by region II and negatively by region III, whereas promoter activity in the forward orientation was regulated negatively by region II and positively by region I. Thus the 52-bp stretch of region II had a dual function, enhancing expression in the reverse orientation and suppressing it in the forward orientation. These results demonstrated that the activity of the At1g71850-At1g71860 bidirectional promoter was modulated by complex interactions between both positive and negative cis-acting elements. These findings will enhance our understanding of the regulatory mechanisms of plant bidirectional promoters.

Functional analysis of cis-acting sequences regulating root-specific expression in transgenic tobacco

Two different length fragments, RSF1 and RSF2 which contained the cis-acting sequences of root-specific gene TobRB7, were isolated from tobacco genome. The abilities of these fragments to direct root-specific expression were studied by fusing them to the β-glucuronidase (GUS) report gene with different directions. After the recombined vectors were transformed into tobacco, the expression pattern was performed by histochemical staining and the quantitative analysis of GUS activity. The data suggested that the cis-acting element of TobRB7 gene direct GUS expression not only as root-specific but also as bidirectional. In our studies, the short fragment, RSF2, performed stronger activity than RSF1 with any direction. The stronger activity of GUS expression was determined by reverse inserting of RSF1 or RSF2 than positive inserting.