Latest revision as of 17:02, 19 May 2016

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Extension of the standard compability to RFC10 and RFC25

[http://2012.igem.org/Team:TU_Munich Team TU_Munich 2012] extended the standard compability to RFC10 and RFC25 by adding the

Editing Part:BBa J04450 (section)

=> Pictures

Adeno-associated Virus

Explanation of the Capsid coding plasmid
The Adeno-associated Virus - Capsid coding BioBricks

Explanation of the Vector Plasmid
The Adeno-associated Virus - Vector plasmid BioBricks

The Adeno-associated Virus - Other system parts

Virus Construction Kit

info AT biobricks DOT org

Viral Vectors are modified viruses that are used in molecular biology to transfer genetic material into desired cells. The adventage of viral vectors is that the different viral mechanismns can be employed to transduce the target cell in an specific and efficient manner. This process is called transduction when eucaryotic cells are the target of the gene transfer.

Key properties of a viral vector

• Safety: Viral vectors are often engineered on the basis of an human infectious virus. To reduce the risks for people that handle the virus and patient of an viral vector base therapy the genetic material of the viurs is manipulated in a way to knock-out the ability of the viral vector to reproduce. To reach this requirement the genes coding for the production of the viral capsid are often provided in trans to ensure that the viral vector does not contain the information for
• Low toxicity: For any use the effect the viral vector has on the transduced cells is important to consider. The [http://en.wikipedia.org/wiki/Cytopathic_effect cytopathic effect] describes the effect of the physiology and morphology the infection with a viral particle has. For the use in vivo the immune response that is triggered by the viral vector has to be considered.
• Stability: Some viruses evolved a genome organisation that makes it possible to rearrage its genome easily. This feature has been used in the evolution to outflank the immune system of host organisms successfully but is absolute not desired in gene transfer with viral vectors and has to be reduced therefor.
• Cell type specificity: Many viruses evolved in a way that they are able to transduce many different cell types giving them a wide host cell range. For experimental and therapeutical applications a more narrow cell specificity can be desired. There viral vector systems should provide the possibility to modify the viral tropism in order to target specific cell types.
• Identification: ????

Main applications of viral vectors:

Double stranded DNA Viruses

The Adenovirus

The Simian virus 40

The SV40 is a non-enveloped polyomavirus virus, containing a double stranded DNA genome of 5.2 kb. In comparism to other gene transfer vectors the genome of the virus is circular. Thus it lacks the terminal repeat regions characterizing many other viral vectors with linear genomes. The icosahedral capsid of the virus is formed by three virus-encoded proteins (VP1, VP2, and VP3), transcribed by the SV40 late promoters (LP). On the opposite strand the early (EP) promoters are located, driving the expression of the large T antigen (Tag) and a small t antigen (tag). Near a unique BglI site, there are the regulatory sequences, the origin of replication, and packaging signals. According to that the early and late polyadenylation signals are close to each other as well.

SV40 derived vectors have repeatedly proven to be effective, for example in gene delivery to the liver or hematopoietic progenitor cells. The vectors can be stable produced at a very high titer, lacking in immunogenicity and providing high levels of transgene expression in both resting and dividing cells. The principle limitation is the size of insert (≤5 kb) which can be packaged by SV40-derived vectors.

Single stranded DNA Viruses

The Adeno-associated Virus

In the iGEM competition 2010 the Team Freiburg bioware constructed a Virus Construction Kit that makes the Adeno-associated virus (AAV2) available for all users of the parts registry. The Adeno-associated virus is a well studied vector for eukaryotic gene transfer.

Double stranded RNA Viruses

Single stranded RNA (+) Viruses

Single stranded RNA (-) Viruses

Double stranded RNA retro-transcribing Viruses

Single stranded RNA retro-transcribing Viruses

The Lentivirus

References: 1)http://expasy.org/viralzone/