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Research Digest Synopses of Research Articles Artifi cial Prions Created from Portable Control Elements For decades, scientists accepted that “seed.” These growing masses are then slow growing protein aggregates from the nucleic acids, DNA and RNA, packed thought to divide with the help of becoming infectious prions. Previous with thousands of protein-coding genes, “chaperones,’’ cellular proteins that aid in research showed that one end of the were the sole purveyors of genetic protein folding and transport, resulting in yeast protein, Sup35p, is critical for information; all inherited traits, from smaller prion particles called propagons. turning this normal housekeeping eye color to shoe size, must be stored The propagons are then distributed to enzyme into a prion. The “prion-forming and expressed through nucleic acid both mother and daughter cells during domain’’ of Sup35p consists of two mechanisms. But prions are an exception. division, thereby infecting the next segments: one stretch rich in the amino These misshapen proteins are capable of generation of cells. Though this theory of acids glutamine and asparagine and growing, replicating, and infecting other the prion life cycle was proposed a few another made up of several, small series cells—that is, they are heritable. And all years ago, scientists are still working out of amino acids, called oligopeptides. without a scrap of DNA. Most famous as the underlying molecular mechanisms Osherovich and colleagues had earlier the culprit behind bovine spongiform found another yeast protein,