The evolution of cell types in animals: emerging principles from molecular studies

The evolution of cell types in animals: emerging principles from molecular studies

Detlev Arendt

Nature Reviews Genetics 9, 868-882 (November 2008) | doi:10.1038/nrg2416

focus

Canon 24-105 Caffeine for Focus

Dear Santa,

I’ll fill all the f*cking papers needed for a grant to get this lovely toy. Please, consider tickling whatever necessary to tickle so I can get one of those. I’ve being naughty as always am, but this have nothing to do with me, it’s just about satisfying my deep voyeur inclination, which may help me improve.

Thank you,

OC

PS For the microscope it’s OK, don’t care about it.

Drosophila Piwi functions in Hsp90-mediated suppression of phenotypic variation

Drosophila Piwi functions in Hsp90-mediated suppression of phenotypic variation

Vamsi K Gangaraju, Hang Yin, Molly M Weiner, Jianquan Wang, Xiao A Huang & Haifan Lin

Nature Genetics (2010) doi:10.1038/ng.743

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It’s somehow stupid the way this kind of papers are presented in press releases. I grabbed this references from physorg.com, where the heading goes like that:

For decades, biology textbooks have been clear – our traits are the product of our genes. But a new study by Yale University researchers published Dec. 26 in Nature Genetics suggests another mechanism can regulate variations of traits even in genetically identical individuals.

Somewhere in the text is hidden:

Genes do play a role in protecting against harmful variations but probably work through actions of the molecules piRNA and Hsp-90.

Yeah, right, that’s really news! Genes play a role through their encoded products…

If you go and read the whole stuff, and hopefully the paper, you aren’t really overwhelmed by new evidence that genes act through their products, but the paper is excellent: this is an original mechanism of genetic expression regulation and it’s fun to read about it. But, the way it’s presented call for IDiots to read it superficially and draw conclusions that are somehow IDiotic:

It’s getting more and more difficult for those who cling to evolution to escape the facts.

The whole DNA system and now even some extraneous factors are designed to PROTECT against harmful mutations. Just about any random, unspecified mutation is either useless or harmful. There are very few random mutations that are actually good. This is not to be confused with the switching on or off of already existing genes which would in most cases be the source for speciation.

Tiring, isn’t it?

2011 : l’année des cellules souches reprogrammées sans modification de leur génome ?

Entre la technique originale de production des iPS par Yamanaka et ce jour, il y a eu des progrès quant aux techniques utilisées, notamment pour éviter la modification permanente du génome qui est source de complications – majeures les complications.

Au moins deux grandes tendances ont déjà été publiées, utilisant :

les produits des gènes impliqués à la re-programmation, les protéines : Zhou et al., Generation of Induced Pluripotent Stem Cells Using Recombinant Proteins, Cell Stem Cell (2009), doi:10.1016/j.stem.2009.04.005

Groundbreaking work demonstrated that ectopic expression of four transcription factors, Oct4, Klf4, Sox2, and c-Myc, could reprogram murine somatic cells to induced pluripotent stem cells (iPSCs) (Takahashi and Yamanaka, 2006), and human iPSCs were subsequently generated using similar genetic manipulation (Takahashi et al., 2007; Yu et al., 2007). To address the safety issues arose from harboring integrated exogenous sequences in the target cell genome, a number of modified genetic methods have been developed and produced iPSCs with potentially reduced risks (for discussion, see Yamanaka, 2009, and references therein). However, all of the methods developed to date still involve the use of genetic materials and thus the potential for unexpected genetic modifications by the exogenous sequences in the target cells. Here we report generation of protein-induced pluripotent stem cells (piPSCs) from murine embryonic fibroblasts using recombinant cell-penetrating reprogramming proteins. We demonstrated that such piPSCs can long-term self-renew and are pluripotent in vitro and in vivo

les molécules codantes pour les protéines en question, des mRNA : Warren et al., Highly Efficient Reprogramming to Pluripotency and Directed Differentiation of Human Cells with Synthetic Modified mRNA, Cell Stem Cell (2010), doi:10.1016/j.stem.2010.08.012

Clinical application of induced pluripotent stem cells (iPSCs) is limited by the low efficiency of iPSC derivation and the fact that most protocols modify the genome to effect cellular reprogramming. Moreover, safe and effective means of directing the fate of patient-specific iPSCs toward clinically useful cell types are lacking. Here we describe a simple, non integrating strategy for reprogramming cell fate based on administration of synthetic mRNA modified to overcome innate antiviral responses. We show that this approach can reprogram multiple human cell types to pluripotency with efficiencies that greatly surpass established protocols. We further show that the same technology can be used to efficiently direct the differentiation of RNA-induced pluripotent stem cells (RiPSCs) into terminally differentiated myogenic cells. This technology represents a safe, efficient strategy for somatic cell reprogramming and directing cell fate that has broad applicability for basic research, disease modeling, and regenerative medicine.

Tom Roud n’aura pas à attendre longtemps pour voir sa prédiction réalisée Emmett Brown est passé par là…

massive coincidence

HT Monado @ Science Notes

Pharmacogenomics: will the promise be fulfilled?

Pharmacogenomics: will the promise be fulfilled?

Russ B. Altman, Heyo K. Kroemer, Catherine A. McCarty, Mark J. Ratain and Dan Roden

Nature Reviews Genetics 12, 69-73 (January 2011) | doi:10.1038/nrg2920

Self-organization, Natural Selection, and Evolution: Cellular Hardware and Genetic Software

Self-organization, Natural Selection, and Evolution: Cellular Hardware and Genetic Software (pdf)

Brian R. Johnson and Sheung Kwan Lam

BioScience December 2010 / Vol. 60 No. 11, 879–885 doi:10.1525/bio.2010.60.11.4

Identification of SOX3 as an XX male sex reversal gene in mice and humans

Identification of SOX3 as an XX male sex reversal gene in mice and humans

Edwina Sutton, James Hughes1, Stefan White, Ryohei Sekido, Jacqueline Tan2, Valerie Arboleda, Nicholas Rogers, Kevin Knower, Lynn Rowley, Helen Eyre, Karine Rizzoti, Dale McAninch, Joao Goncalves, Jennie Slee, Erin Turbitt, Damien Bruno, Henrik Bengtsson, Vincent Harley, Eric Vilain, Andrew Sinclair, Robin Lovell-Badge and Paul Thomas

J Clin Invest. doi:10.1172/JCI42580.

Evolution and its rivals

An issue of Synthese, free for a few more days. Go get the pdf and read them when you have some free time.

1. Introduction, by Glenn Branch

2. Can’t philosophers tell the difference between science and religion?: Demarcation revisited, by Robert T. Pennock
3. Are creationists rational?, by John S. Wilkins
4. Foiling the Black Knight, by Kelly C. Smith
5. Information theory, evolutionary computation, and Dembski’s “complex specified information”, by Wesley Elsberry and Jeffrey Shallit
6. Design and its discontents, by Bruce H. Weber
7. The science question in intelligent design, by Sahotra Sarkar
8. Intelligent design in theological perspective, by Niall Shanks and Keith Green
9. The non-epistemology of intelligent design: its implications for public policy, by Barbara Forrest
10. Evolution and atheism: Has Griffin reconciled science and religion?, by James H. Fetzer