The amount of the signaling protein Delta, shown in red, in an intestinal stem cell (ISC) determines the fate of its daughter cells. In panel A, an ISC that has just produced an enterocyte (EC) shows a high level of Delta (arrow). In panel B, an ISC that has just produced an enteroendocrine cell (ee) lacks detectable Delta. Adult stem cells call the shots when it comes to their daughters' destinies. That's the take-home lesson for adult stem cells in the intestines of fruit flies, according to new studies by researchers at the Howard Hughes Medical Institute (HHMI). The researchers found that intestinal stem cells make important decisions about their fate by communicating directly with their daughter cells, instructing them to become one of two possible cell types.
