Effects of bm47 deletion on viral replication and transcription of Bombyx mori nucleopolyhedrovirus / 病毒学报

Bombyx mori nucleopolyhedrovirus (BmNPV) bm47 gene is found in all sequenced lepidopteran nucleopolyhedroviruses (NPVs). It is one of the core genes of NPVs. However, the role of bm47 in the biological cycle of NPV remains unknown. In this study, the Red recombination system was used to knock out bm47 from BmNPV to construct bm47-ko-Bacmid in E. coli BW25113 system. Then bm47 gene was introduced back to the viral genome using the Bac-to-Bac system to create the repair virus bm47-re-Bacmid. TCID50 assay and real-time PCR (qPCR) were used to evaluate the effects of bm47 deletion on viral DNA replication, gene transcription, and protein expression. qPCR results showed that bm47 knock-out had no significant effect on viral DNA replication. However, the qPCR results showed that bm47-ko-Bacmid significantly decreased the transcription levels of early gene lef-3, late gene vp39, and very late gene p10 at 48 h and 72 h after viral transfection of BmN cells (P < 0.05). This work will provide a foundation for further studies on the biological function of BmNPV bm47 in viral replication and transcription.

The connection between tumor and ubiquitin-ribosomal protein S27a, ubiquitin and ribosomal protein / 生物工程学报

Ubiquitin-ribosomal protein S27a(UBRPS27a) is a fusion protein of Ubiquitin and ribosomal protein. The N-terminal is ubiquitin and C-termina is ribosomal protein S27a with a high conservative zinc finger domain of the C2-C2 type. When it was expressed in eukaryotes,The intact fusion protein were rapidly processed to free ubiquitin monomer and ribosomal protein S27a (RPS27a). Ubiquitin degradated proteins particularly and selectively in cell and RPS27a is indispensable for translation. This multifunctional ribosomal protein is expressed at high levels in a wide variety of actively proliferating cells and tumor tissues and is a representative characteristic of various tumor cells. In our preliminary study of this protein in the silkworm,RPS27a also be found express highly in actively proliferating cells. The precise functional role of each ribosomal protein is largely unknown and many ribosomal proteins have extraribosomal functions apart from the particle. In this article, we review the recent research on the connection between tumor and this fusion protein, Ubiquitin-Proteasome Pathway and ribosomal protein. These research may indicate the origin and development of tumor, provide the basis for clinical diagnosis of cancer and the novel therapeutic targets for the treatment of malignant tumors.

The research progress of one member of the EF-hand superfamily--troponin C / 生物工程学报

The EF-hand superfamily is a large group of proteins which contain EF-hand motif formed by helix-loop-helix. These proteins always have the ability of binding metal ions or forming dimmers. Troponin C, known as having ability of binding Ca2+, is one member of the EF-hand superfamily. Troponin C interacts with troponin I and troponin T, forming a troponin complex which takes part in regulating muscle contraction. It is interesting that troponin C was also found in non-muscular tissue, and its function was proved to be different from that of troponin C found in muscular tissue. To date, a lot of researches about troponin C have been carried out widely. However, most of them focused on vertebrate, seldom were done on invertebrate. Our group carried out a research on troponin C from silkworm, a model organism of insects, aiming to clarify the structure and function of silkworm troponin C. Here, we mainly discuss the characters of the EF-hand superfamily and the classification, structure and function of troponin C . We also introduced our work about silkworm troponin C briefly, hoping of making a little contribution to the research of invertebrate troponin C.

The basics of 14-3-3 protein family and research progress on therapeutic applications of 14-3-3 protein / 生物工程学报

The 14-3-3 proteins comprise a family of highly conserved acidic protein with subunit molecular mass 28-33kD and are widely found in different eukaryotic cells. 14-3-3 proteins were the first polypeptides shown to have phosphoserine/threonine (pSer/Thr) binding properties which firmly established its importance in cell signaling. 14-3-3 proteins tend to form dimeric proteins to modulate protein-protein interactions. 14-3-3 proteins have been shown to contribute to the regulation of such crucial cellular processes as metabolism, signal transduction, cell cycle control, cell growth and differentiation, apotosis, protein trafficking, transcription, stress responses and malignant transformation. Many reports link 14-3-3 to disorders, particularly the neurological disorders and cancer. The 14-3-3 test has been used for the diagnosis of prion diseases. 14-3-3 could be exploited for therapeutic purposes. In this review, we discuss the structure, function of 14-3-3 protein and the related research progress in therapeutic applications.

Progresses in the structure and function of Kazal-type proteinase inhibitors / 生物工程学报

Proteinase inhibitors are widely distributed in many living organisms and play crucial roles in many biological processes, particularly in regulating the proteinase activity spatially and temporally. However, The Kazal family of serine protease inhibitors is one of the most important and extensively studied protease inhibitor families. This type of protease inhibitor normally consists of one or several domains. Every domain has a highly conserved sequence structure and molecular conformation. It is found that contact residues are hyper variable, which are responsible for the interaction of inhibitors and proteinases. Most of them are in the solvent exposed loop. But P1 residue is the key active site of the interaction between inhibitor and enzyme. The types of the amino acid at P1 site likely play an important role in causing different inhibitory activity. The substitutions at the contact residues cause significant effects on the association constant. By using the Laskowski algorithm, the Ki values of a Kazal domain against six serine proteinases can be predicted from the domain' s sequence alone. At present there are many Kazal proteinase inhibitors found in the organisms, which show important biological functions. This article gives a comprehensive review of the newer developments in the characters and the interaction of the Kazal-type inhibitors.

Computational prediction of microRNA genes in silkworm genome / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

MicroRNAs (miRNAs) constitute a novel, extensive class of small RNAs (approximately 21 nucleotides), and play important gene-regulation roles during growth and development in various organisms. Here we conducted a homology search to identify homologs of previously validated miRNAs from silkworm genome. We identified 24 potential miRNA genes, and gave each of them a name according to the common criteria. Interestingly, we found that a great number of newly identified miRNAs were conserved in silkworm and Drosophila, and family alignment revealed that miRNA families might possess single nucleotide polymorphisms. miRNA gene clusters and possible functions of complement miRNA pairs are discussed.

Antibacterial Cecropin and Its Application on Transgenic Plants for Bacterium Resistance / 中国生物工程杂志

Cecropin is a kind of heat-durable and broad-spectrum antibacterial polypeptides which has strong effect against bacteria,fungi,virus and some pathogenic microorganisms.Today Cecropin has been widely applied into plant genetic engineering,antiviral study,and inhibiting tumor cell proliferation.Its Structure-function relationship,antibacterial mechanism,and the application on transgenic plants for bacterium resistance was reviewed.Expression of Cecropin in plants has a great application potential in bacterium resistance.Deep analyses and research of molecular structure and action mechanism can promote the transgenic plants antibacterial research.

Expression of human interleukin-11 in cell culture and larvae of silkworm / 生物工程学报

A recombinant transfer vector, pBacIL-11, containing hIL-11 cDNA of 546 nucleotides lacking leader sequence was constructed and co-transfected into BmN cells with linearized BmBacPAK(modified BmNPV) DNA for construction of a recombinant baculovirus carrying the hIL-11 gene. Southern hybridization analysis suggested that the recombinant baculovirus DNA contained hIL-11 cDNA fragment. RNA dot blotting demonstrated that the hIL-11 gene was transcribed. The recombinant baculovirus has a strong infectivity to BmN cell line and to silkworm larvae and pupae. Specific hIL-11 bands were detected from all the samples of cell extract, culture supernatant, haemolymph of larvae and pupae by SDS-PAGE analysis. Biological activity of the expressed product was determined with IL-11 dependent B9-11 cell line and by MTT colorimetric assay, which indicated that biologically active rhIL-11 protein was overexpressed in BmN cell line and in silkworm larvae and pupae.

The Advancement about Baculovirus Surface Display System / 微生物学通报

At present, microbe surface display system mainly involves phage surface display system, bacte- rial surface display system, yeast surface display system and virus surface display system. Baculovirus sur- face display system is a new type of eukaryote surface display system which developed based on deeply un- derstanding of construction and function of virus genome in recent years. Through fused expression with vi- ral capsid or membrane proteins exogenous peptides can be displayed on the surface of the virus and formed hedgehog-shape "fake virus". Baculovirus surface display system was characterized by safeness and high performance, furthermore, this system can complete post-translation processing and modification of protein to enhance the bioactivity of exogenous product. Combined with the author’s experimental work, this paper briefly introduces the mechanism and traits of this system and summarizes the newest research development on its application in the field of monoclonal antibody preparation, new-type vaccine development, genes transduction and genes therapy. It is believed that the system above may show extensive application through further improvement and optimization.