Enhancer detection in the ascidian Ciona intestinalis with transposase-expressing lines of Minos.

Germline transgenesis with a Tc1/mariner superfamily Minos transposon was achieved in the ascidian Ciona intestinalis. Transgenic lines that express transposases in germ cells are very useful for remobilizing transposon copies. In the present study, we created transposase-expressing lines of Minos in Ciona. A Ciona gene encoding protamine (Ci-prm) is expressed in the testes and sperm. Transgenic lines expressing Minos transposase in the testes and sperm were created with a cis-element of Ci-prm, and used for enhancer detection. Double-transgenic animals between transposase lines and a transgenic line with an enhancer detection vector passed on several independent enhancer detection events to subsequent progeny. This technique allowed us to isolate transgenic lines that express GFP in restricted tissues. This system provides an easy and efficient method for large-scale enhancer detection in Ciona intestinalis.     

Germline transgenesis of the chordate Ciona intestinalis with hyperactive variants of sleeping beauty transposable element

Background: Transposon‐mediated transgenesis is an excellent method for creating stable transgenic lines and insertional mutants. In the chordate Ciona intestinalis, Minos is the only transposon that has been used as the tool for germline transformation. Adding another transposon system in this organism enables us to conduct genetic techniques which can only be realized with the use of two transposons. Results: In the present study, we found that another Tc1/mariner superfamily transposon, sleeping beauty (SB), retains sufficient activity for germline transformation of C. intestinalis. SB shows efficiencies of germline transformation, insertion into gene coding regions, and enhancer detection comparable to those of Minos. We have developed a system for the remobilization of SB copies in the C. intestinalis genome by using transgenic lines expressing SB transposase in the germ cells. With this system, we examined the manner of SB mobilization in the C. intestinalis genome. SB shows intrachromosomal transposition more frequently than Minos. Conclusions: SB‐based germline transformation and the establishment of a new method that uses its frequent intrachromosomal transposition will result in breakthroughs in genetic approaches that use C. intestinalis together with Minos. Developmental Dynamics 242:30–43, 2013. © 2012 Wiley Periodicals, Inc.     

Efficient transposition of a single Minos transposon copy in the genome of the ascidian Ciona intestinalis with a transgenic line expressing transposase in eggs

Transgenesis with transposons is an important technique for studying genetic functions. In the ascidian Ciona intestinalis, methods for germline transformation with the Tc1/mariner transposon Minos have been established. A system to remobilize a single Minos copy in the genome is needed to refine this transgenic technique. In this study, such an experimental system was established with a transgenic line expressing Minos transposase in eggs. In the eggs of a double transgenic animal from a cross between the egg transposase line and a transgenic line having a single Minos insertion, the transposon was transposed into new positions of the Ciona genome, thus creating new insertions. Some of the new insertions caused enhancer detection. The majority of the new insertion sites were mapped on different chromosomes from that of the transposon donor. This characteristic of Minos is in contrast to that of the Sleeping Beauty transposon, which causes frequent intrachromosomal transposition. Developmental Dynamics 239:1076–1088, 2010. © 2010 Wiley‐Liss, Inc.     

Culture of Ciona intestinalis in closed systems.

Improvements in closed-system culturing methods for marine invertebrates are important prerequisites for the generalized use of transgenic lines. We discuss here the effects of several closed-system conditions on the growth and survival of the solitary ascidian, Ciona intestinalis. In Shimoda, close to the sea, a small-tank system was used to ensure that tanks and systems were reasonably equipped, water exchange was rapid, and animals separated to minimize the risk of infection. In Gif-sur-Yvette, an inland site, we tried to determine the optimal conditions to limit handling operations, and to save artificial seawater by avoiding water pollution. A mixture of at least two types of live algae was better than any single-organism diet. With these maintenance protocols, we were able to obtain several generations of Ciona intestinalis, including several transgenic lines. Because these systems make it easier to rear Ciona intestinalis in laboratories, they increase the potentialities of this model organism for research.     

Gene expression profiles in Ciona intestinalis stigmatal cells: insight into formation of the ascidian branchial fissures.

Gill slits, a series of openings in the pharyngeal epithelium, are characteristic features of the hemichordate and chordate body plans. In ascidians, these openings, called stigmata, are formed in the branchial sac during juvenile development. Multiple whole-mount in situ hybridization analyses based on approximately 1,500 genes expressed in Ciona intestinalis juveniles, identified 28 genes expressed predominantly in the stigmatal cells. Expression patterns of these stigmatal genes were classified into four different categories. On the basis of these findings, we have been able to show that the peripheral region of a stigma consists of at least three different regions. The expression of a Dlk1-like gene was detected in nonciliated cells during the stigma perforation and division and was maintained in the basal region of the elliptical stigma. Expression of meichroacidin, tektin A1, and tektin B1 orthologs during the differentiation of the ciliated stigmatal cells suggests that some of the molecular mechanisms involved in sperm differentiation might be recruited for the stigma development, or vice versa. Components of the cilia such as alpha-tubulin and rootletin were also expressed in the stigmatal cells. These genes might facilitate further analyses regarding the evolution of the branchial fissures and the development of the ascidian stigmata.     

Cloning of a glycosylphosphatidylinositol-anchored alpha-2-macroglobulin cDNA from the ascidian, Ciona intestinalis, and its possible role in immunity

Molecular approaches were used to study thiolester-containing genes in the ascidian, Ciona intestinalis. RT-PCR, RACE and genome mining revealed that this animal expresses not only conventional alpha-2-macroglobulin (alpha2m) and two forms of C3 but also a gene encoding a glycosylphosphatidylinositol (GPI)-anchored alpha2m. Previously, GPI-anchored alpha2ms have been reported only for humans and mice. We propose that GPI-anchored alpha2ms constitute a third subgroup of the alpha2m superfamily and may represent an important evolutionary stage in the phylogeny of the thiolester containing proteins. Its occurrence in an ascidian shows its origin pre-dates the evolution of the vertebrates. In C. intestinalis this GPI-anchored alpha2m, designated Ciona alpha2m-GPI, is expressed in the hepatopancreas, circulating coelomic blood cells and the gut of adults. It is also expressed in 3-5 days old larvae. Its tissue distribution coupled with its sequence characteristics and unusual domain structure indicate that the encoded protein probably assists in host defence by entrapping and inhibiting proteases from micro-organisms.     

A web-based interactive developmental table for the ascidian Ciona intestinalis, including 3D real-image embryo reconstructions: I. From fertilized egg to hatching larva.

The ascidian chordate Ciona intestinalis is an established model organism frequently exploited to examine cellular development and a rapidly emerging model organism with a strong potential for developmental systems biology studies. However, there is no standardized developmental table for this organism. In this study, we made the standard web-based image resource called FABA: Four-dimensional Ascidian Body Atlas including ascidian's three-dimensional (3D) and cross-sectional images through the developmental time course. These images were reconstructed from more than 3,000 high-resolution real images collected by confocal laser scanning microscopy (CLSM) at newly defined 26 distinct developmental stages (stages 1-26) from fertilized egg to hatching larva, which were grouped into six periods named the zygote, cleavage, gastrula, neurula, tailbud, and larva periods. Our data set will be helpful in standardizing developmental stages for morphology comparison as well as for providing the guideline for several functional studies of a body plan in chordate.     

Th1/Th2、Tc1/Tc2亚群在乙肝肝硬化患者中的作用

目的 :探讨乙肝肝硬化患者外周血 (PBMC)中CD4 和CD8 T细胞内Th1和Th2类细胞的平衡状态 ,探明Th1、Th2类细胞在乙肝肝硬化中的作用。方法 :乙肝肝硬化患者CD4 T细胞和CD8 T细胞中IFN γ 和IL 4 细胞的百分率 ,观察乙肝肝硬化患者Th1 Th2、Tc1 Tc2比例的变化。结果 :乙肝肝硬化患者PBMC中CD4 ,CD8细胞 ,CD4 CD8比值与健康对照者相比无统计学差异 (P >0 0 5 ) ,Th1细胞及Tc1细胞百分率为 8 8% ,9 0 % ,较健康对照者 7 5 % ,7 7%升高 (P <0 0 5 )。结论 :乙肝肝硬化患者外周血T细胞亚群发生Th1类偏移 ,在乙肝肝硬化的发生和发展中可能起重要作用     

Site-directed mutagenesis in the active site of the herpes simplex virus type 1 thymidine kinase gene

The thymidine kinase (TK) of herpes simplex virus type 1 (HSV-1) contains three regions of homology to other ATP utilizing enzymes. We have altered one region of the protein, which seems to play an important role in phosphorylating substrates by site-directed mutagenesis. When the aspartate 162 was changed to asparagine, the enzyme lost its activity. To identify the inactive protein, expressed by a vaccinia vector in eukaryotic cells, a monospecific antiserum against a bacterial tryptophan E-HSV-1 TK fusion protein was made. These results support the suggestion that aspartate 162 is essential for the enzymatic activity.     

肾综合征出血热患者TH1/TH2、Tc1/Tc2亚群比例及有关细胞因子变化的研究

目的：探讨肾综合征血热（HFRS）患者TH1样和TH2样细胞平衡状态以及血清中细胞因子的变化，方法：收集HFRS患者和健康个体血清，采用夹心ELISA方法测定IFN－γ、IL－4和TNF－α的水平，分离PBMC，采用三色流式细胞术分析HFRS患者CD4^ T细胞和CD8^ T细胞中IFN－γ^ 和IL－4^ 细胞的百分率。观察HFRS患者TH1／TH2，Tc1/Tc2比例的变化，比较了不同病程和病情HFRS患者血清中上述指标的变化，结果：HFRS患者血清中TH1类和TH2类细胞因子水平均明显升高，其中IFN－γ和IL－4的平均水平显著高于健康个体（P＝0．016，P＝0．019）。HFRS患者PBMC中TH1、TH2、Tc1,Tc2细胞的平均百分率均高健康个体Tc细胞比例的改变较TH细胞明显，TH1样细胞的比例较TH2样细胞变化明显。发热期患者血清中IFN－γ、IL－4和TNF-α的水平明显升高于恢复期患者，发热期的重症患者的IFN－γ水平升高较轻症明显。结论：HFRS患者血清中IFN－γ和IL－4水平以及PMBMC中TH1、TH2、Tc1和Tc2细胞的比例均有所升高，发热期的患者和重症HFRS患者上述参数变化更明显，表明感染机体总体的免疫平衡偏向TH1类。     

Germline mutations of the LKB1 (STK11) gene in Peutz-Jeghers patients

Germline mutations of the LKB1 (STK11) serine/threonine kinase gene (chromosome 19p13.3) cause Peutz-Jeghers syndrome, which is characterised by hamartomas of the gastrointestinal tract and typical pigmentation. Peutz-Jeghers syndrome carries an overall risk of cancer that may be up to 20 times that of the general population. Here, we report the results of a screen for germline LKB1 mutations by DNA sequencing in 12 Peutz-Jeghers patients (three sporadic and nine familial cases). Mutations were found in seven (58%) cases, in exons 1, 2, 4, 6, and 9. Five of these mutations, two of which are identical, are predicted to lead to a truncated protein (three frameshifts, two nonsense changes). A further mutation is an in frame deletion of 6 bp, resulting in a deletion of lysine and asparagine; the second of these amino acids is conserved between species. The seventh mutation is a missense change in exon 2, converting lysine to arginine, affecting non-conserved amino acids and of uncertain functional significance. Despite the fact that Peutz-Jeghers syndrome is usually an early onset disease with characteristic clinical features, predictive and diagnostic testing for LKB1 mutations will be useful for selected patients in both familial and non-familial contexts.     

趋化性细胞因子对人Tc1和Tc2细胞内Ca~(2+)浓度变化的影响

为了探讨趋化性细胞因子在体外对人Tc1和Tc2亚群细胞内Ca2 + 浓度变化的影响 ,从PBMC中分离纯化CD8+ T细胞 ,在特定细胞因子及细胞因子抗体作用下 ,体外定向诱导出能长期培养的Tc1和Tc2细胞系 ,用免疫荧光染色结合流式细胞术分析对其进行鉴定后 ,通过流式细胞术检测在趋化性细胞因子刺激前后 ,细胞内Ca2 + 浓度的变化。发现受SDF 1作用后 ,Tc1及Tc2细胞内Ca2 + 浓度变化均不明显 ,而IP 10刺激后 ,Tc1及Tc2细胞内Ca2 + 水平在短时间内明显上调 ,且在Tc1胞内的上升幅度远高于Tc2细胞 ,在MIP 1β刺激后 ,也观察到类似趋势 ;受Eotaxin刺激后 ,Tc1及Tc2细胞内Ca2 + 水平均有微小上升 ,在Tc2细胞内的上升幅度略高于Tc1细胞。说明Tc1和Tc2细胞受趋化性细胞因子作用后 ,细胞内Ca2 + 浓度有不同程度的变化 ,且与趋化性细胞因子受体的表达呈现一定的相关性。     

Human cytochrome P450 2E1 and sulfotransferase 1A1 coexpressed in Chinese hamster V79 cells enhance spontaneous mutagenesis

Genetic engineering of target cells for investigating the genotoxicity associated with specific xenobiotic‐metabolizing enzymes is useful for elucidating metabolic activation and inactivation processes. We constructed a V79‐derived cell line expressing both human cytochrome P450 (CYP) 2E1 and human sulfotransferase (SULT) 1A1. We previously reported that this cell line (V79‐hCYP2E1‐hSULT1A1) efficiently activates various important pro‐genotoxicants. Here we present data on the expression level and stability of the heterologous enzymes, measured by immunoblotting, enzyme activities, and mutagenic responses to CYP2E1‐ and SULT1A1‐dependent promutagens. Unexpectedly, these cells demonstrated greatly elevated spontaneous gene mutation frequencies (determined at the Hprt locus), and elevated frequencies of sister chromatid exchange, as compared with control V79 cells and V79‐derived lines engineered for other enzymes. Therefore, V79‐hCYP2E1‐hSULT1A1 cells require regular cleansing in aminopterin‐containing medium when used for Hprt gene mutation assays. In a 4‐week time course without such selection, V79‐hCYP2E1‐hSULT1A1 demonstrated a progressive increase in the spontaneous mutant frequency from 2.9 to 155 × 10^?6. This phenomenon was moderately, strongly, and completely prohibited in the presence of CYP2E1 inhibitor 1‐aminobenzotriazole, SULT1A1 inhibitor pentachlorophenol and both in combination, respectively. This protection indicates that the enhanced spontaneous mutagenicity involves the activity of the expressed enzymes rather than being caused by an accidental genetic alteration that might have occurred during transfection. We postulate that human CYP2E1 and SULT1A1 activate an endogenous cellular molecule or a medium component to become mutagenic. It will be challenging to identify this compound and to see whether it is involved in spontaneous mutagenesis and carcinogenesis in vivo. Environ. Mol. Mutagen., 2010. © 2009 Wiley‐Liss, Inc.