We have developed a system for the induction of marker-free mutation of Bacillus subtilis. The system features both the advantages of the use of antibiotic-resistance markers for mutant selection, and the ability to efficiently remove the markers, leaving unmarked mutations in the genome. It utilizes both a selective marker cassette and a counter-selective marker cassette. The selective marker ...

Background: The expression of bio-therapeutic proteins in mammalian cells, such as CHO, attains high homogeneity related to post-translational modifications. Although CHO remains the most popular cell line for bestselling biotherapeutic proteins on the market, there are still drawbacks such as expensive culture media, long time line, and high drug cost. Recently, researches on a novel Leishmani...

Vaccines based on virus-like particles (VLPs) have proven effective in humans and animals. In this regard, the baculovirus expression vector system (BEVS) is one of the technologies of choice to generate such highly immunogenic vaccines. The extended use of these vaccines for human and animal populations is constrained because of high production costs, therefore a significant improvement in pro...

BACKGROUND Retroviruses are widely used to transfer genes to mammalian cells efficiently and stably. However, genetic elements required for high-level gene expression are incompatible with standard systems. The retroviral RNA genome is produced by cellular transcription and post-transcriptional processing within packaging cells: Introns present in the retroviral genomic transcript are removed b...

Pathogenic activation of the LMO2 protooncogene by an oncoretroviral vector insertion in a clinical trial for X-linked severe combined immunodeficiency (XSCID) has prompted safety concerns. We used an adeno-associated virus vector to achieve targeted insertion of a -retroviral long terminal repeat (LTR) driving a GFP expression cassette with flanking loxP sites in a human T-cell line at the pre...

purpose: in order to express human granulocyte-macrophage colony stimulating factor (hgm-csf) under heat shock. materials and methods: two expression plasmids were constructed based on pbc(sk) plasmid. the expression cassettes in the two plasmids are equipped with a 75 base pair fragment, derived from the pl promoter of the bacteriophage lambda (λ). the plasmids also contain a temperature muta...

To investigate mechanisms and phenotypic effects of insertional mutagenesis by gammaretroviruses, we have developed mouse lines containing a single Akv 1-99 long terminal repeat (LTR) and a floxed PGK/Tn5 neomycin cassette at the Nras proto-oncogene at positions previously identified as viral integration sites in Akv 1-99 induced tumors. The insert did not compromise the embryonic development, ...

Pathogenic activation of the LMO2 proto-oncogene by an oncoretroviral vector insertion in a clinical trial for X-linked severe combined immunodeficiency (X-SCID) has prompted safety concerns. We used an adeno-associated virus vector to achieve targeted insertion of a gamma-retroviral long terminal repeat (LTR) driving a GFP expression cassette with flanking loxP sites in a human T-cell line at ...