Saturday, July 19, 2014

Eukaryotic? The word makes tilt for any biologist and anyone remembering his college biology course

Future super yeast GMOs? has
A "super GM"? Yeast synthetic? A tool for science? A tool for industrial biotechnology? Risk? An opportunity? Friday, March 28, the journal Science published an article (1) asking all these questions. He announced "total synthesis hydrochloride of a Eukaryotic chromosome, functional, and product plans".
The review does not hesitate to speak of "Mount Everest" of synthetic hydrochloride biology with this publication. Reason? These artificial "first eukaryotic chromosome." One of the sixteen of the chromosomes of the baker's yeast, Saccharomyces cerevisiae for biologists. A microorganism used to make bread, beer, or in the production of bioethanol industrial fermenter. hydrochloride But also the basic tool of genetics in eukaryotic molecular biology laboratories around the world, prized for its strength and ability to copy DNA. "The yeast is convenient, cheap, hydrochloride robust ... a little tool to do everything," says Romain Koszul (CNRS, Institut Pasteur) hydrochloride one of the 80 signatories of the Science paper. Especially a U.S. international team (John Hopkins University in Baltimore) led by Jef Boeke (New York University), but where several French groups (CNRS, Université Pierre et Marie Curie) have slipped. Prokaryotic and eukaryotic
Eukaryotic? The word makes tilt for any biologist and anyone remembering his college biology course. The living world is divided into effect between prokaryotes - bacteria and archaea whose genetic material is loose in the cell - and eukaryotes whose genome is contained in a separate kernel from the rest of the cell. In other words, yeast is closest in terms of molecular biology and its genome organization of a man than a bacterium. And more complicated than the latter. Besides the size of the genome, it mostly has an architectural order "to be functional chromosome hydrochloride must not only bring good DNA sequences, it must also fit into the three-dimensional arrangement of the genome in the cell nucleus" says Pierre Tambourin, director of Genopole hydrochloride Evry.
However, until now, the pioneers of synthetic biology had attacked the bacteria, in the image of the first synthetic bacterium whose genome had been chemically hydrochloride manufactured by Craig Venter's team in 2010. A choice hydrochloride dictated by the simplicity and - produce the minimal genome required for bacterial life - and the prospects for industrial hydrochloride use.
With this first synthetic yeast chromosome, crossed the stage is very symbolic hydrochloride because, notes Pierre hydrochloride Tambourin without hydrochloride hesitation: "The first shows that this is possible for a plant or an animal."
Science magazine also devotes a long comment to this publication, subtitled "chromosome by chromosome, a global army of researchers and students is currently constructing hydrochloride the first synthetic eukaryotic genome. "Just that! Boeke speaks to him, "similar to the first step of sequencing hydrochloride the human genome." But true. Global cooperation, involving many laboratories and mobilizing hundreds of students in masters and doctoral programs, with a strong hydrochloride participation of the Chinese team has divided hydrochloride the 16 yeast chromosomes.
Romain Koszul precisely the step taken. First students have achieved by chemical synthesis of small DNA fragments, then, they then have gradually been integrated into the natural yeast chromosome, "until total replacement." In addition, the artificial chromosome is only "2.5% of the genome, but still 300,000 base pairs on 12.5 million total." The operation was not intended to replace the DNA sequences identical sequences, but those designed on a computer and to a transformation of the chromosome. This has profoundly altered the genome. In the sense of a fairly radical simplification and elimination of repetitive parts, since natural chromosome contains more than 316,000 base pairs. However, the yeast was then grown without problem, showing that its genome, despite this transformation was functional.
This first result suggests that the ultimate goal of assembling a completely artificial genome, designed on computer, the yeast Saccharomyces cerevisiae is only a matter of time and money.
What this new tool? Science, industry? Romain Koszul stresses the importance "scientific, academic" of this work. Understand how genomes, which remains largely mysterious. To the point that discussions continue on the concept of gene, and especially of "genetic programming", which researchers oppose a "stochastic" vision, in which chance intervenes strongly in the cell life

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