Faculty of 1000

Post-publication peer review

Cells and drugs and roll-on/roll-off

Posted by rpg on 24 March, 2010

Everybody loves a good structure. Here’s one of the prototype foamy virus (PFV) integrase in complex with DNA ends. The integrase is the complex that binds the termini of viral DNA and catalyses its insertion into the host genome. Nasty piece of work, and incidentally one that has ‘nasty biophysical properties‘—at least the one from HIV and related retroviruses. Fortunately for the future development of retroviral drugs, Stephen Hare from Imperial College and his colleagues managed to persuade the integrase from PFV to not only bind to DNA, but form a complex that was active in solution and amenable to crystallization. Fred Dyda of the NIH says

This outstanding achievement also speaks volumes about the value of high resolution experimental structures of assembled complexes, as it appears that previous models of intasomes based on fragmentary structural information and a lot of imagination have not been reliable.

C’est n’est pas un stem cell

Elsewhere this week, surprising news from the world of plant biology. A favourite tool of plant biologists is the callus, a mass of seemingly totipotent cells. Callus can be induced starting from virtually any differentiated plant tissue and is the basis for the remarkable ability of plants to regenerate the whole zucchini from just about any tissue, as any gardener is well aware when it comes to rooting out dandelions. The surprise is that the callus resembles the growing tip of roots, and is not the result of a simple reprogramming process to an undifferentiated state.

Vorsprung duck technik

In an amazing piece of German engineering scholarship, the itineraries of 16,363 cargo ships in 2007 were used to construct a network map. And if I could get access to the paper, I’d post a pretty picture here. Sorry. Anyway, the point is that this map could tell us lots about the movement of bioinvasive marine species, seeing as bulk dry carriers and oil tankers are the primary vectors for such beasties, as they hitch rides in the ballast. Jonathan Belmaker and Lewi Stone of Tel Aviv University add,

the network is almost scale-free since there are several large highly connected ports through which all smaller ports transact their trade. This property makes the ship network more prone to the spreading and persistence of bioinvasive organisms.

L’amour est comme un papillon

This is rather sweet, as well as pretty mind-blowing from an evolutionary point of view. A duplicated opsin—a visual pigment—in the Heliconius spp of butterfly evolved by positive selection, giving the insect the ability to discriminate between pigments. Wing pigments in the same butterfly underwent coincident evolution, which might help explain why the yellow wing pigments of Heliconius are so varied in the UV range, compared, with its less colourful relatives.

This is a beautiful example of how evolutionary and functional information together can provide strong evidence on the nature of an evolutionary adaptation.

And finally, a quick cytoskeleton fix. We’ve known for a while that short actin oligomers can anneal in vitro to form fibres. Turns out that this also happens in yeast cells at least; which means that if you sequester all the monomers, you can still build filaments close to the plasma membrane at endocytic sites. Could be important if you’re a budding yeast faced with a shed load of latrunculin A.


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