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Science Magazine

http://www.sciencemag.org/cgi/content/abstract/296/5566/340

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InGENEuity

By inserting a gene for a yellow coat into a mouse egg, David Largaespada has done more than create a rodent that resembles a Japanese cartoon character. Largaespada and colleagues are excited about the applications of their new method of gene transfer, which uses a segment of DNA known as a transposon and an enzyme called the "Sleeping Beauty" transposase. Experimenting with a fertilized mouse egg, researchers injected a linear piece of DNA containing a transposon with the gene responsible for making a yellow-colored coat and the Sleeping Beauty transposase into a fertilized mouse egg. After injection, the enzyme facilitated the transfer of the transposon from the DNA segment to a mouse chromosome, ultimately resulting in a yellow-coated mouse. Largaespada envisions a number of applications for this method. He is currently exploring how to transfer genes directly into cells of the body to treat diseases such as cancer and cystic fibrosis. He also sees the possibility of genetically-engineered animals to create organs for transplants or proteins to be used in drug therapy.

References:

Largaespada, David A. et al (2002). Mammalian germ-line transgenesis by transposition. Proceedings of the National Academy of Sciences 99 (April 2nd): 4495-4499.

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Proceedings of the National Academy of Sciences

http://www.pnas.org/cgi/content/abstract/99/7/4495

Discovery Genomics

http://www.discoverygenomics.net/

University of Minnesota Cancer Center, Mouse Genetics Laboratory

http://www.cancer.umn.edu/page/cores/mouselab.html

Abstracts of the above articles.

Heart Warming Story

Researchers at the University of Texas at Austin and the University of Texas Southwestern Medical Center at Dallas have discovered a gene linked to congenital heart disease, the leading noninfectious cause of death among infants. The gene appears to control heart chamber formation. Building on previous work, the researchers discovered that when the gene "Bop" was deleted, the hearts in mouse embryos developed abnormally. Further investigation revealed Bop encodes a protein key to embryonic cells developing into cardiac muscle. Additionally, they also discovered Bop contributes to the activation of another gene, Hand2, already known to be vital to the formation of the right and left ventricles. Because of the close similarity in the genetics of heart formation among many diverse species, the researchers are confident that this research can be readily applied to humans. They are currently analyzing the DNA of children with heart conditions to establish this connection and pave the way for preventative treatments.

References:

Srivastra, Deepak et al (2002). Bop encodes a muscle-restricted protein containing MYND and SET domains is essential for cardiac differentiation and morphogenesis. Nature Genetics 31 (May 02): 25-32.

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Nature Genetics

http://www.nature.com/ng

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Substantial Advances

Although the biological origin of more recent fossils is fairly evident, the fossils of ancient microscopic organisms has long been difficult to identify and show to be biological in origin. Consequently, it is difficult to refute those who challenge claims of the discovery of the fossil evidence of ancient microscopic creatures. However, that is now changing with the application of a new technique utilizing laser-Raman spectroscopy. Scientists from the University of California at Los Angeles and the University of Alabama have adapted this technology to determine what rocks are made of. The sensitivity of this technique to the carbon signal of organic matter and its non-intrusive nature make it ideal for studying microscopic fossils. The research team applied the technique to examine some of the oldest known specimens of microbe fossils. The results allowed the leader of the team, J. William Schopf, to categorically confirm the biological origin of these fossils. There now remains little doubt that life on Earth dates back over 3.5 billion years. This new method of analysis not only substantiates the biological origin of ancient fossils but also confirms the reasoning that lay at the foundation of much existing work.

References:

Schopf, J William et al (2002). Laser-Raman imagery of Earth's earliest fossils. Nature 416 (March 7th): 73-76.

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Nature

http://www.biomedcentral.com/news/20020408/03/

Laser Raman Spectroscopy

http://www.uwo.ca/ssw/services/raman.html

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Stemming a Tide of Controversy?

Researchers from the Howard Hughes Medical Institute and the Salk Institute have revealed strong evidence that adult neural stem cells from the brains of rats can develop into functioning neurons. This development that may allow scientists to further distance themselves from using controversial embryonic stem cells. Previous studies showed that adult cells possess protein markers indicative of neuron development but the work of Charles F. Stevens, Hong-jun Song and Fred H. Gage provides evidence that they do in fact develop into neurons. By isolating stem cells from the hippocampus of rat's brains and tagging them with fluorescent molecules, the researchers were able to track the cells' progress. Along with similarly tagged normal adult neurons these cells were cultured together on a base of supporting astrocytes, cells that produce the chemical signals that trigger neuronal growth. By doing this, the team could also observe whether the neurons originating from the stem cells would also integrate into the circuitry of the existing neurons. Observations demonstrated that the stem cells developed axons and dendrites structures as well protein markers characteristic of neurons. Although the team observed fewer synapses between the stem-cell neurons and the existing neurons, they were able to establish the existence of electrical signals and neurotransmitters indicating that the synapses were functioning. There is still much investigation to be done, but this research demonstrates that adult stem cells may have therapeutic potential.

References:

Stevens, Charles F. et al (2002). Neural stem cells from adult hippocampus develop essential properties of functional CNS neurons. Nature Neuroscience 5 (May 1st): 438-445.

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Nature Neuroscience

http://www.nature.com/cgi-taf/dynapage.taf?file=/neuro/journal/v5/n5/abs/nn844.html