Development of the binary vector pTACAtg1 for stable gene expression in plant: Reduction of gene silencing in transgenic plants carrying the target gene with long flanking sequences

Genetic modification in plants helps us to understand molecular mechanisms underlying on plant fitness and to improve profitable crops. However, in transgenic plants, the value of gene expression often varies among plant populations of distinct lines and among generations of identical individuals. This variation is caused by several reasons, such as differences in the chromosome position, repeated sequences, and copy number of the inserted transgene. Developing a state-of-art technology to avoid the variation of gene expression levels including gene silencing has been awaited. Here, we developed a novel binary plasmid (pTACAtg1) that is based on a transformation-competent artificial chromosome (TAC) vector, harboring long genomic DNA fragments on both sides of the cloning sites. As a case study, we cloned the cauliflower mosaic virus 35S promoter:β-glucuronidase (35S:GUS) gene cassettes into the pTACAtg1, and introduced it with long flanking sequences on the pTACAtg1 into the plants. In isolated transgenic plants, the copy number was reduced and the GUS expressions were detected more stably than those in the control plants carrying the insert without flanking regions. In our result, the reduced copy number of a transgene suppressed variation and silencing of its gene expression. The pTACAtg1 vector will be suitable for the production of stable transformants and for expression analyses of a transgene.     

Structural analysis of Arabidopsis thaliana chromosome 3. II. Sequence features of the 4,251,695 bp regions covered by 90 P1, TAC and BAC clones.

To deduce the entire sequence of the top arm of the Arabidopsis thaliana chromosome 3, the sequence determination was performed on a total of 90 P1, TAC and BAC clones chosen according to our sequencing strategy. Sequence features of the resulting 4,251,695 bp regions were analyzed with various computer programs for similarity search and gene modeling. As a result, a total of 941 potential protein-coding genes were identified. The average density of the genes identified was 1 gene per 4210 bp. Introns were observed in 73% of the genes, and the average number per gene and the average length of the introns were 3.6 and 159 bp, respectively. These sequence features are essentially identical to those of chromosomes 3 and 5 in our previous reports. The regions also contained 14 tRNA genes when searched by similarity to reported tRNA genes and the tRNA scan-SE program. The sequence data and information on the potential genes are available through the World Wide Web database KAOS (Kazusa Arabidopsis data Opening Site) at http://www.kazusa.or.jp/kaos/.     

Use of Thiophilic Adsorption Chromatography for the One-Step Purification of a Bacterially Produced Antibody Fab Fragment without the Need for an Affinity Tag

Thiophilic adsorption chromatography (TAC) was employed for the purification of a recombinant F_ab fragment of the antibody IN-1 from the periplasmic protein fraction of Escherichia coli. Adsorption of the F_ab fragment to the T-gel was achieved at a high concentration of ammonium sulfate and turned out to be independent of the presence of a His₆ tag or Strep tag or of the human or murine nature of the C_H1 and C_L domains (subclass IgG1/κ). Elution was effected by means of a decreasing salt gradient, yielding fractions with the correctly assembled, heterodimeric F_ab fragment at high purity. Interestingly, the single substitution of an alanine residue with phenylalanine in the CDR-L1 of the F_ab fragment significantly enhanced the retention on the column so that quantitative elution necessitated prolonged application of a low-salt buffer. Our findings suggest that TAC is generally suitable for the isolation of bacterially produced F_ab fragments and support the notion that aromatic side chains play an important role in the interaction with the affinity matrix. This method should prove valuable in the production of proteins for in vivo applications as might be the case for the F_ab fragment of the antibody IN-1, which promotes axonal regeneration in the central nervous system.     

Proteomic analysis of B-cell malignancies

The identification of proteins aberrantly expressed in malignant B-cells can potentially be used to develop new diagnostic, prognostic or therapeutic targets. Proteomic studies of B-cell malignancies have made significant progress, but further studies are needed to increase our coverage of the B-cell malignant proteome. To achieve this goal we stress the advantages of using sub-cellular fractionation, protein separation, quantitation and affinity purification techniques to identify hitherto unidentified signalling and regulatory proteins. For example, proteomic analysis of B-cell plasma membranes isolated from patients with mantle cell lymphoma (MCL) identified the voltage-gated proton channel (HVCN1,[1]). This protein has now been characterised as a key modulator of B-cell receptor (BCR) signalling and abrogation of HVCN1 function could have a role in the treatment of B-cell malignancies dependent on maintained BCR signalling [2]. Similarly, proteomic studies on cell lysates from prognostic subtypes of CLL, distinguished by the absence (UM-CLL) or presence (M-CLL) of somatic hypermutation of the immunoglobulin heavy chain locus identified nucleophosmin 1 (NMP1) as a potential prognostic marker [3,4]. Thus, targeted proteomic analysis on selected organelles or sub-cellular compartments can identify novel proteins with unexpected localisation or function in malignant B-cells that could be developed for clinical purposes.     

可转化人工染色体(TAC)文库载体DNA的制备

对可转化人工染色体(TAC)pYLTAC747NH/sacB文库载体DNA的制备条件进行了较系统的模索和研究.结果表明,该文库载体经碱裂解法提取、QIAGEN Plasmid Mini kit纯化后,可获得较纯净的载体DNA.对其闭环载体DNA分别用不同酶量的Hinid Ⅲ酶切处理,经琼脂糖凝胶电泳检测得出其最佳Hind Ⅲ完全酶切条件为2 U Hind Ⅲ/μg闭环载体DNA、37℃酶切30 min;分别用0.5 MBU和1 MBU HK脱磷酶/μg对其线性载体DNA进行脱磷处理,经电泳和载体自连产物电转化检测表明其适宜的完全脱磷条件为1 MBU HK脱磷酶/μg线性载体DNA,30℃脱磷1 h;将所制备的线性载体DNA与λ DNA/Hind Ⅲ酶切片段进行连接,连接产物转化频率较高,其电转化大肠杆菌DH10B感受态细胞频率可达到9.6×10s.     

Cardiac-specific Traf2 overexpression enhances cardiac hypertrophy through activating AKT/GSK3β signaling

Tumor necrosis factor superfamily ligands provoke a dilated cardiac phenotype signal through a common scaffolding protein termed tumor necrosis factor receptor-associated factor 2 (Traf2); however, Traf2 signaling in the adult mammalian cardiac hypertrophy is not fully understood. This study was aimed to identify the effect of Traf2 on cardiac hypertrophy and the underlying mechanisms. A significant up-regulation of Traf2 expression was observed in mice failing hearts. To further investigate the role of Traf2 in cardiac hypertrophy, we used cultured neonatal rat cardiomyocytes with gain and loss of Traf2 function and cardiac-specific Traf2-overexpressing transgenic (TG) mice. In cultured cardiomyocytes, Traf2 positively regulated angiotensin II (Ang II)-mediated hypertrophic growth, as detected by [³H]-Leucine incorporation, cardiac myocyte area, and hypertrophic marker protein levels. Cardiac hypertrophy in vivo was produced by constriction of transverse aortic (TAC) in TG mice and their wild-type controls. The extent of cardiac hypertrophy was evaluated by echocardiography as well as by pathological and molecular analyses of heart samples. Traf2 overexpression in the heart remarkably enhanced cardiac hypertrophy, left ventricular dysfunction in mice in response to TAC. Further analysis of the signaling pathway in vitro and in vivo suggested that these adverse effects of Traf2 were associated with the activation of AKT/glycogen synthase kinase 3β (GSK3β). The present study demonstrates that Traf2 serves as a novel mediator that enhanced cardiac hypertrophy by activating AKT/GSK3β signaling.     

Evaluation of immune responses and oxidative stress in donkeys: Immunological studies provoked by Parascaris equorum infection

This study aimed to assess the effects of Parascaris equorum (P. equorum) in infected donkeys through evaluation the oxidative stress and different gene parameters in infected tissues. Fifty donkeys were examined in Giza Zoo abattoir from the period of January to March 2021. Blood and sera samples were collected from each examined donkey. P. equorum were subjected for identification through scanning electron microscope study and the infected tissues were subjected into gene expression analysis using two genes; interleukin 1β (IL1- β); and pro-inflammatory cytokines (TNF-α) with assessment of the antioxidant and free radicals released from the animals during the infection. Eighteen donkeys were positive for P. equorum adult or larvae by postmortem examination of the intestine and abdomen with prevalence rate of 36 %. The examined infected donkeys with P. equorum showed significantly higher of Total antioxidant capacity (TAC) levels and the serum malondialdehyde (MDA) 2.45 ± 0.53 than that in non-infected control donkeys. The levels of AST enzyme were 278.54 ± 0.45 while ALT enzyme was 14.97 ± 0.87 which was significantly higher than that of control negative donkeys. The infected donkeys with P. equorum showed significantly upregulation of the TNF-α and IL-1β which classify according to number of collected worms. The P. equorum infected donkeys exerted at least 100 eggs of parasite in feces. The fecal egg count was marked decreased after treatment with moxidectin. Moxidectin is considered a novel active ingredient that has a marvelous result with high persistency and protection for long time, in addition to, broad spectrum activity and low or no resistance. We recommend the periodical deworming with different molecules as more economic and lifesaving over a single treatment every 12 months parallel with parasitic testing.