Scott Sternson has always wondered what drives behavior, especially those fundamental motivations required for survival. Hunger, for example, is so crucial that it must be evolutionarily “hard-wired” deep within the brain. After all, as Sternson observes, “if the animal doesn’t eat, it dies.” read story
Embryonic stem (ES) cells are plain enough to look at, forming a nondescript clump within the hollow ball of an early embryo. But that generic character is key to their magical rejuvenating potential. Unlike all other cells, which are preordained toward a specialized form and function, ES cells have a clean slate. The developing embryo can mold them into any cell type it needs.
Sugar and spice and X chromosome twice—that’s what girls are made of, despite the fact that this double dollop of X chromosomes can be deadly for females of any species.
read story (pdf)
Telomeres, the long chains of DNA letters capping the ends of chromosomes, seem like a Dr. Seuss creation. What they spell out, in the language of DNA, amounts to gibberish.
read in full issue (pdf)
Using robots and other high-throughput technologies, the researchers screened more than 32,000 protein combinations, identifying 2,846 unique pairwise interactions in their study. Even so, says Fields, “We’ve only scratched the surface of what’s out there.” read in full issue (pdf)
“About 40 percent of the sequences in our genome, and in the mouse genome, are actually transposon sequences,” Xu says. Those transposons are no longer active, however, but are the molecular relics of an era when transposons ran rampant through mammalian genomes. read in full issue (pdf)
Colorectal tumors take the lives of more adult Americans than any other cancer except lung cancer, even though colon cancer is almost always curable by surgery if detected early enough. read in full issue (pdf)
For a cell, destroying proteins is as essential as building them. The job of mincing proteins is performed by enzymatic machines called proteasomes. “Proteasomes affect almost all biological processes in the cell,” Verma says. By their deliberate destruction of regulatory proteins, they orchestrate activities from cell division to cell death. read in full issue (pdf)
Although he has never taken a biology class, Gene Myers’s work gets a lot of notice from biologists. Fifteen years ago, Myers, whose formal training is in computer science, mathematics, physics, and engineering, co-wrote an article for the Journal of Molecular Biology that would become the most highly cited scientific paper of the decade. read story
PTC124 sticks to ribosomes — the cells’ protein factories — and prompts them to interpret a premature stop codon as a normal codon. Instead of aborting assembly of the protein, the ribosome inserts a protein building block — an amino acid — and continues making a complete protein chain until it encounters the normal termination codon, which the ribosome correctly interprets as a stop. read story