Thursday, September 3, 2009

Viral reassortment, genome transplantation and more in my picks of the week from RB
Another week has gone by and some very interesting blog posts have been aggregated into Every week [see my opening post on the matter], I'll select some blog posts I consider particularly interesting in the field of molecular biology [see here to get a sense of the criteria that will be used] and list them here for you to check out.

This week, three blog posts made the cut:

1) Reassortment is a phenomenon in which genome segments of different viruses (with segmented genomes) infecting a single cell, can mix and lead to a viral particle containing segments of different origins, i.e with a new viral genome.
For this to happen, you need an individual infected by various viral strains (that is, a mixed infection), in which the reassortment can take place.
"Reassortment, notoriously, can generate rapid large changes in the personality of the virus. Pandemic influenzas have been reassortants, unrecognized by the population’s immune systems".
Ian York from Mystery Rays from Outer Space, discusses a recent article looking for evidence of mixed infection in humans, a necessary precursor to reassortment, from a collection of over 1000 influenza samples.

By using high-throughput sequencing, the authors show that ~0.5% of their samples — half a dozen individuals — were potentially mixed infections. Ian nicely discusses the implications of this and gives a nice summary of the results.

2) Daniel Ocampo-Daza at Ego sum Daniel comments on a recent article reporting a method to clone a Mycoplasma mycoides genome in yeast and then transplant it into a related species, Mycoplasma capricolum, producing viable colonies of M. mycoides (yes... Craig Venter is listed as an author). Daniel briefly comments on the methodology used and on the media hype these sorts of projects generate.

3) Respectful Insolence brings us an interesting and very critical post on a recent PNAS article describing a miRNA-mediated negative autoregulatory feedback loop in the estrogen receptor-α-dependent pathway, a pathway particularly important in breast cancer.

The following headline appeared in The Telegraph regarding this paper, a few days ago:
“Scientists two years from developing 'potential cure' for breast cancer”
Surely you realize how silly this is.

Orac speaks very strongly about the irresponsible and overblown media coverage the article has received (partly attributable to one of the authors?) and critically discusses some of the results, in light of these reports.

That's it for this week. Stay tuned for more MolBio Research Highlights!

Some of the articles discussed in this week's selected posts:

Ghedin, E., Fitch, A., Boyne, A., Griesemer, S., DePasse, J., Bera, J., Zhang, X., Halpin, R., Smit, M., Jennings, L., St. George, K., Holmes, E., & Spiro, D. (2009). Mixed Infection and the Genesis of Influenza Virus Diversity Journal of Virology, 83 (17), 8832-8841 DOI: 10.1128/JVI.00773-09

Lartigue, C., Vashee, S., Algire, M., Chuang, R., Benders, G., Ma, L., Noskov, V., Denisova, E., Gibson, D., Assad-Garcia, N., Alperovich, N., Thomas, D., Merryman, C., Hutchison, C., Smith, H., Venter, J., & Glass, J. (2009). Creating Bacterial Strains from Genomes That Have Been Cloned and Engineered in Yeast Science DOI: 10.1126/science.1173759

Castellano, L., Giamas, G., Jacob, J., Coombes, R., Lucchesi, W., Thiruchelvam, P., Barton, G., Jiao, L., Wait, R., Waxman, J., Hannon, G., & Stebbing, J. (2009). The estrogen receptor- -induced microRNA signature regulates itself and its transcriptional response Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.0906947106

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