Archive for August 16th, 2013

The haplotype-resolved genome and epigenome of the aneuploid HeLa cancer cell line

16 August, 2013

See on Scoop.itVirology News

The HeLa cell line was established in 1951 from cervical cancer cells taken from a patient, Henrietta Lacks. This was the first successful attempt to immortalize human-derived cells in vitro1. The robust growth and unrestricted distribution of HeLa cells resulted in its broad adoption—both intentionally and through widespread cross-contamination2—and for the past 60 years it has served a role analogous to that of a model organism3. The cumulative impact of the HeLa cell line on research is demonstrated by its occurrence in more than 74,000 PubMed abstracts (approximately 0.3%).

 Haplotype resolution facilitated reconstruction of an amplified, highly rearranged region of chromosome 8q24.21 at which integration of the human papilloma virus type 18 (HPV-18) genome occurred and that is likely to be the event that initiated tumorigenesis. We combined these maps with RNA-seq6and ENCODE Project7 data sets to phase the HeLa epigenome. This revealed strong, haplotype-specific activation of the proto-oncogene MYC by the integrated HPV-18 genome approximately 500 kilobases upstream, and enabled global analyses of the relationship between gene dosage and expression. 

Cervical cancer / HPV graphic from Russell Kightley Media

Ed Rybicki‘s insight:

We have known for years that HeLa cells contain integrated HPV-18 genome(s) – now we know that they can be very probably causally linked to the cervical cancer that killed Ms Lacks, and led to her immortal cells becoming so much a part of modern molecular biology.

This is a tour de force in modern biology, and shows that, even 62 years later, new findings are coming out of old material.

Even if it is immortal – which poor Ms Lacks was not.

See on www.nature.com

A baculovirus-mediated strategy for full-length plant virus coat protein expression and purification

16 August, 2013

See on Scoop.itVirology and Bioinformatics from Virology.ca

Background

Garlic production is severely affected by virus infection, causing a decrease in productivity and quality. There are no virus-free cultivars and garlic-infecting viruses are difficult to purify, which make specific antibody production very laborious. Since high quality antisera against plant viruses are important tools for serological detection, we have developed a method to express and purify full-length plant virus coat proteins using baculovirus expression system and insects as bioreactors.

Conclusions

The expression of a plant virus full-length coat protein fused to the baculovirus Polyhedrin in recombinant baculovirus-infected insects was shown to produce high amounts of the recombinant protein which was easily purified and efficiently used to generate specific antibodies. Therefore, this strategy can potentially be used for the development of plant virus diagnostic kits for those viruses that are difficult to purify, are present in low titers or are present in mix infection in their plant hosts.

 

Baculovirus image from own collection

Ed Rybicki‘s insight:

I love the way plant virology / biotechnology now makes use of the whole spectrum of mol biol: this paper uses cDNA clones of an RNA plant virus, via E coli, to make recombinant baculoviruses, to express a fusion protein in insect cells – to make sera for detection of the plant virus by ELISA and other serological assays.

I’m biased because my lab uses ALL of these techniques (and I would have made the protein via agroinfiltration in plants), but this sort of science has really come of age.  One that I have lived through, incidentally, as cloning was VERY young when I started out – and ELISA had only just been invented.

I also know Renato quite well – so parabens, meu amigo!

See on www.virologyj.com