Pandoraviruses have a size approaching 1 micrometer and a blob-like shape resembling some types of bacteria. The genome of the larger variant, Pandoravirus salinus, was reported to contain 2556 putative protein-coding sequences, of which only 6% had recognizable relationships with genes from other known organisms. Phylogenetic approach reveals that these viruses do not cluster in other giant virus families, thereby forming a distinct clade.[9] The dissimilarity of the remaining genes to any that are known led the researchers to speculate that this virus may represent a previously unknown branch of the tree of life. However, experts not involved in the study have called that suggestion premature because supporters provide no evidence for the idea.

The research on this virus is scarce.

Dear Karima AI-Salihi

Thank you for your comment.

As you pointed out, these viruses are not well known even about its life cycle.

As there are few evidences to support of this idea, discussion of this idea may be premature.

I have to learn about these viruses more and more.

Yours sincerely,

Narumi Uno.

Premature but not worthless, since somebody has to start sooner or later. And if pandoravirus are largely misterious, mimivirus are better understood but still pretty large. On my side, I would be glad to test new viral vectors for neuroscience applications; so if you produce one, le me know...

That is great Francesco Roselli really we have to try .

Well, some facts are already out there. the genome does not go to the nucleus but does replicate in the cytoplams, genomes are sequenced and should not be too complex to knock down the virus to produce replication-deficient viruses. splice in some gfp, and you get an idea of where the virus is. infectivty seems to extend to vertebrates. but first, what is the killer application?

Instead of elaborating on Pandraviruses, let me tell you very simply, that these are not suitable as vectors for transferring human genome.

Jai, you are indeed right. But this is also a place for some wild thoughts!

Another possible issue with using a pandravirus or similar large virus as a basis for gene transfer is that the large number of viral proteins. These viral proteins increase the chance of the viral vector inducing an immune response in vivo

First of all, you need to create a replication-deficient Pandravirus. For this, we need a better understanding of the life cycle and which proteins you can delete or maintain in order to create a split genome approach (like in the production of lentivirus). Probably this virus will be very immunogenic, so the deletiion of undesired proteins may help with this issue.

Are Pandraviruses enveloped? If yes, MAYBE the VSVg could work. But I think that the large size of the particle would prevent concentration by centrifugation due to decreased stability. If no, you could engineer a capsid protein (like the knob protein in adenovirus) to redirect the particle to the target cell.

It is a huge ammount of work, but it would be a nice tool for transgenesis.

Please see the following paper:

GENE THERAPY WITH VIRAL VECTORS

Neeltje A. Kootstra and Inder M. Verma

Laboratory of Genetics, The Salk Institute, La Jolla, California 92037-1099;

email: [email protected], [email protected]

Key Words AAV, retrovirus, lentivirus, adenovirus, HSV

n Abstract A key factor in the success of gene therapy is the development of

gene delivery systems that are capable of efficient gene transfer in a broad variety

of tissues, without causing any pathogenic effect. Currently, viral vectors based on

many different viruses have been developed, and their performance and pathogenicity

has been evaluated in animal models. The results of these studies form the basis for

the first clinical trials for correcting genetic disorders using retroviral, adenoviral, and

adeno-associated viral vectors. Even though the results of these trials are encouraging,

vector development is still required to improve and refine future treatment of hereditary

disorders.