Gene engineering in swine for agriculture

Domestic pigs are the second most important source of meat world-wide, and the genetic improvement of economic traits, such as meat production, growth, and disease resistance, is a critical point for efficient production in pigs. Through conventional breeding and selection programs in pigs, which are painstakingly slow processes, some economic traits, such as growth and backfat, have been greatly improved over the past several decades. However, the improvement of many polygenetic traits is still very slow and challenging to be improved by conventional breeding strategies. The development of reproductive knowledge and a variety of techniques, including foreign gene transfer strategies, somatic cell nuclear transfer（SCNT） and particularly, recently developed nuclease-mediated genome editing tools, has provided efficient ways to produce genetically modified（GM） pigs for the dramatic improvement of economic traits. In this review, we briefly discuss the progress of genomic markers used in pig breeding program, trace the history of genetic engineering, mainly focusing on the progress of recently developed genome editing tools, and summarize the GM pigs which have been generated to aim at the agricultural purposes. We also discuss the specific challenges facing application of gene engineering in pig breeding, and future prospects.

GENE ENGINEERING EB VIRUS MEMBRANE ANTIGEN IN DETECTION OF MA-IgA ANTIBODY(COMPARISON WITH VCA-IgA AND EA-IgA ANTIBODIES)

With gene engineering EB virus membrane antigen as the diagnostic antigen, indirect immunofluo-rescence (IF) assay was used to detect IgA antibody against EB virus membrane antigen (MA-IgA) in sera from 202 nasopharyngeal carcinoma (NPC) patients and 315 controls (normal and patients with other tumors). MA-IgA antibody was positive in 96.8% of the pretreatment NPC patients with a GMT of 1:36.3. MA-IgA detection by this method was more sensitive than EA-IgA detection by IE. In contrast, patients with tumors other than NPC were negative for MA-IgA antibody. 9.1% of VCA-IgA positive persons were MA-IgA positive with a GMT of less than 1:5. No MA-IgA positive was found in VCA-IgA negatives. The results indicated that this method was relatively specific. In the treatment group, the positive rate and GMT of MA-IgA antibody declined with increase in survival time and the decline was faster than VCA-IgA. When recurrence or distant metastasis developed, similar to VCA-IgA and EA-IgA antibodies, the positive rate and GMT of MA-IgA antibody increased to its pretreatment level. Therefore, MA-IgA detection might be valuable in the early diagnosis and monitor of NPC.

Neurodegenerative diseases and gene engineering

Totally three articles focusing on ＂molecular biological mechanism by which gene modification and RNA interference techniques interfere Parkinson’s disease and Alzheimer’s disease＂ are published in three issues. We hope that our readers find these papers useful to their research.

Identification of a gene engineering antibody against cystic echinococcosis in liver

OBJECTIVE: To identify a gene engineering antibody against cystic echinococcosis in liver. METHODS: A single chain of variable fragment of human antibodies (ScFvs) was selected from the library by using affinity selection technique with the recombinant antigen on solid surface. The positive clones were demonstrated by ELISA and their DNA sequences were also determined. RESULTS: The DNA sequence data showed that the antibody gene is composed of 768bp. In addition, a specific combination capacity with recombinant Echinococcus granulosus antigen B (r-EgB) was demonstrated by ELISA. CONCLUSION: The obtained gene engineering antibody against r-EgB may have potential implications in immunological treatment and drug targeting delivery.

A remarkable progress in breeding new rice line through gene engineering

Much progress has been made in the research of breeding new rice line through gene engineering by Life Science College of Fudan Univ, Shanghai, and the Plant Science Res Inst of Shanghai Acad of Agri. It was the first time internationally that the research adopted a man-combined gene, taking agrobacterium as car-

Molecular Cloning of a Cytosolic G6PDH Gene from Populus Suaveolens and Its Expression to Improve the Cold Resistance of Tobacco Plants

Glucose-6-phosphate dehydrogenase (G6PDH,EC 1.1.1.49) is the first and main regulated enzyme of oxidative pentose phosphate pathway (OPPP),catalyzing the conversion of glucose-6-phosphate to 6-phospho-gluconolactone and playing important roles in the growth and development of plants. It is preciously reported that the enhancement of freezing resistance of Populus suaveolenscuttings is clear related to the distinct increase in cytosolic G6PDH activity. Here,a 1697 bp cDNA fragment (PsG6PDH) is amplified by RT-PCR from cold-induced total RNA of the freezing-tolerant P. suaveolens. A sequence analysis showed that PsG6PDH coding region had 1 530 bp and encoded 510 predicted amino acid residues. Genomic Southern analysis revealed that the isoform is encoded by a few copies of the gene in the poplar genome. The cloned gene PsG6PDHis cloned into binary vector pBI121 and used to transform tobacco. PCR and Southern blotting results verified integration of this gene into the genome of tobacco. Moreover,cold treatment experiments and membrane defense enzymeactivity analysis confirmed that overexpression of the PsG6PDHgene could enhance the tolerance to cold or frigid stresses in transgenic plants.

中国杨树分子遗传改良的研究现状(英文)

Poplars are among the most important deciduous tree species in China. China is replete with natural resources of poplars. Poplars have a number of good characteristics, including fast growth rate, high yield, many uses, easiness of tissue culture and small gene group that make them well suited as a model system for the application of genetic engineering in forest trees. In the last decade, much progress has been made in genetic improvement of poplar species in China. Modern biotechnology is an important tool for genetic improvement in forest trees, and its applications to genetic improvement in poplars, which covers genetic transformation, gene expression, construction of genetic linkage map, QTLs (quantitative trait loci) identification and molecular assisted selection are reviewed in this paper. At the same time, the existing problems and outlook about the application of modern biotechnology to genetic improvement in forest trees are also discussed.

Gene-guided OX40L anchoring to tumor cells for synergetic tumor“self-killing”immunotherapy

The low objective response rates and severe side effects largely limit the clinical outcomes of immune checkpoint blockade(ICB)therapy.Here,a tumor“self-killing”therapy based on gene-guided OX40L anchoring to tumor cell membrane was reported to boost ICB therapy.We developed a highly efficient delivery system HA/PEI-KT(HKT)to co-deliver the OX40L plasmids and unmethylated CG-enriched oligodeoxynucleotide(CpG).On the one hand,CpG induced the expression of OX40 on T cells within tumors.On the other hand,OX40L plasmids achieved the OX40L anchoring on the tumor cell membrane to next promote T cells responses via OX40/OX40L axis.Such synergistic tumor“self-killing”strategy finally turned“cold”tumors to“hot”,to sensitize tumors to programmed cell death protein 1/programmed cell death ligand 1(PD-1/PD-L1)blockade therapy,and promoted an immune-mediated tumor regression in both B16F10 and 4T1 tumor models,with prevention of tumor recurrence and metastasis.To avoid the side effects,the gene-guided OX40L anchoring and PD-L1 silencing was proposed to replace the existing antibody therapy,which showed negligible toxicity in vivo.Our work provided a new possibility for tumor“self-killing”immunotherapy to treated various solid tumors.

Progress in the Study of Molecular Genetic Improvements of Poplar in China

The poplar is one of the most economically important and intensively studied tree species owing to its wide application in the timber industry and as a model material for the study of woody plants. The natural resource of poplars in China is replete. Over the past 10 years, the application of molecular biological techniques to genetic improvements in poplar species has been widely studied in China. Recent advances in molecular genetic improvements of poplar, including cDNA library construction, gene cloning and identification, genetic engineering, gene expression, genetic linkage map construction, mapping of quantitative trait loci （QTL） and molecular-assisted selection, are reviewed in the present paper. In addition, the application of modern biotechnology to molecular improvements in the genetic traits of the poplar and some unsolved problems are discussed.

TALENs:Customizable Molecular DNA Scissors for Genome Engineering of Plants

Precise genome modification with engineered nucleases is a powerful tool for studying basic biology and applied biotechnology. Transcription activator-like effector nucleases（TALENs）,consisting of an engineered specific（TALE） DNA binding domain and a Fok I cleavage domain,are newly developed versatile reagents for genome engineering in different organisms.Because of the simplicity of the DNA recognition code and their modular assembly,TALENs can act as customizable molecular DNA scissors inducing double-strand breaks（DSBs） at given genomic location.Thus,they provide a valuable approach to targeted genome modifications such as mutations, insertions,replacements or chromosome rearrangements.In this article,we review the development of TALENs,and summarize the principles and tools for TALEN-mediated gene targeting in plant cells,as well as current and potential strategies for use in plant research and crop improvement.