SEATTLE An international team of researchers led by investigators in the U.S. and Germany has shed light on the inner workings of the endocycle, a common cell cycle that fuels growth in plants, animals and some human tissues and is responsible for generating up to half of the Earth's biomass. This discovery, led by a geneticist at Fred Hutchinson Cancer Research Center and reported Oct. 30 in Nature, leads to a new understanding of how cells grow and how rates of cell growth might be increased or decreased, which has important implications in both agriculture and medicine.
"It can be argued that this is the first completely novel cell cycle to be elucidated in more than a two decades," said Bruce Edgar, Ph.D., corresponding author of the paper and a member of the Basic Sciences Division at the Hutchinson Center, referring to the groundbreaking description of the mitotic cell cycle in the same journal in the late 1980s.
Mitosis is the division of a mother cell into two daughter cells that contain identical sets of chromosomes. Endocycling, in contrast, is a special type of cell cycle that skips mitosis. The cell replicates its DNA over and over again without ever dividing into two cells. Endocycles play a crucial role in nature because they generate very large cells in invertebrate animals and plants, as well as some human tissues, such as liver and muscle. Most cells in plants and invertebrate animals such as insects, crustaceans (such as shrimp), mollusks (such as clams, oysters and snails) grow by endocycling.
"When a cell goes through an endocycle, it doubles its DNA, and typically also doubles its size and protein content," said Edgar, also a professor at the Center for Molecular Biology and the German Cancer Research Center in Heidelberg, Germany. "Because of this, one could imagine that promoting just one extra endocycle in the cells of a crop plant or farmed shellfish might double the agricultural yield from that crop," h
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Fred Hutchinson Cancer Research Center