What is an episomal vector?

What is an episomal vector?

The Episomal iPSC Reprogramming Vectors are a non-integrating system that reprograms somatic cells into induced pluripotent stem cells (iPSCs). This product is a mixture of three vectors designed to provide the optimal system for generating transgene-free and virus-free iPSCs in a feeder-free environment.

What is episomal replication?

Episomes, in eukaryotes, are extrachromosomal, closed circular DNA molecules of a plasmid or a viral genome origin, that are replicated autonomously in the host cell and therefore, they bear significant vector potential for the transfer of nucleic acids into cells.

What is transient expression of genes?

Transient expression, more frequently referred to “transient gene expression”, is the temporary expression of genes that are expressed for a short time after nucleic acid, most frequently plasmid DNA encoding an expression cassette, has been introduced into eukaryotic cells with a chemical delivery agent like calcium …

How do Episomes replicate?

Episomes or plasmids are lengths of DNA existing either in the cytoplasm or attached to the chromosome of a bacterium: they replicate in synchrony with the bacterial chromosome, and are thus perpetuated as long as the parent strain exists.

What is Episomal virus?

The human Epstein-Barr virus (EBV) is a double-stranded DNA herpesvirus that is maintained as an episome in the nucleus of a host cell. The viral genome is circular and chromatinized, resembling a small human chromosome in many molecular aspects.

What is episomal HPV?

HPV is an epitheliotropic virus completing its entire productive life cycle as a circular episome in the differentiated squamous epithelium. HPV infects basal epithelial cells, gaining access through a micro-abrasion or wound.

What is a transient vector?

A transient (plasmid DNA is transiently maintained in the nucleus) or stable (plasmid DNA is integrated into the genome of the host cells) transfection of recombinant vector DNA with the insertion of the recombinant transgene of interest into the cultured cell lines is a prevailing tool of choice for molecular and …

What is an inducible expression?

The production of new proteins in response to external stimuli results largely from rapid activation of gene transcription — this is known as inducible gene expression. Inducible genes are highly regulated and must be able to be rapidly and specifically activated in response to stimuli.

What is Episomal plasmid?

episome, in bacteria, one of a group of extrachromosomal genetic elements called plasmids, consisting of deoxyribonucleic acid (DNA) and capable of conferring a selective advantage upon the bacteria in which they occur. A bacterial cell into whose chromosome the viral DNA has become integrated is called a prophage.

Are all plasmids Episomal?

Plasmids are different from episomes, as plasmid DNA cannot link up with chromosomal DNA. The plasmid carries all the information necessary for its independent replication. While not necessary for bacterial survival, plasmids can be advantageous to a bacterium.

What is Episomal infection?

Episomal latency refers to the use of genetic episomes during latency. In this latency type, viral genes are stabilized, floating in the cytoplasm or nucleus as distinct objects, either as linear or lariat structures.

How is HPV replicated?

HPV infects dividing basal epithelial cells where its dsDNA episomal genome enters the nuclei. Upon basal cell division, an infected daughter cell begins the process of keratinocyte differentiation that triggers a tightly orchestrated pattern of viral gene expression to accomplish a productive infection.

What are episomal plasmid expression vectors?

The aim of this review is to highlight episomal expression vectors. Such episomal plasmids are usually based on sequences from DNA viruses, such as BK virus, bovine papilloma virus 1 and Epstein–Barr virus.

What are the conditions for transient transgene expression from episomal replication?

This requires presence of oriP in the plasmid vector and overexpression of EBNA1 in the host cell. It should be noted that transient transgene expression benefits from episomal replication only if production time will be longer than 2 or 3 days. Only then the effect becomes significant because non-replicating plasmids are lost during cell divisions.

Can episomal vectors be used for gene therapy?

Recently, episomal vectors have also been considered for use in gene therapy . Oncogenes are often expressed at high levels in malignant cells. One approach to gene therapy of human cancer cells is to use antisense strategies to block expression of dominant oncogenes.

What is the replication pattern of SV40?

SV40 exhibits a replication pattern that is uncoupled from the regulatory mechanisms of the host cell, so that each viral genome replicates many times within each cell cycle. As a consequence, transfection of permissive cells with recombinant SV40 vectors results in cell death, limiting this vector to transient expression set-ups.