Researchers identify molecule regulating cell division
Researchers at the European Molecular Biology Laboratory in Heidelberg (EMBL), Germany, have uncovered how cells control whether they should continue to divide or not. The successful growth and development of tissues and indeed organisms depends on controlling which cells divide and which ones die. The fate of cells is decided by signals that are passed from molecule to molecule within the cell. If the signalling pathway breaks down, developmental defects and cancers can result. Barry Thompson and Stephen Cohen of the EMBL investigated a signalling pathway called Hippo, which controls the life and death of cells in the fruit fly. If the Hippo pathway is too active, tissues overgrow because too many cells divide and not enough die. The researchers' aim was to find the connection between the signals and the cellular machinery that drives cell growth. Their findings are published in the latest issue of the journal Cell. The scientists found that a small molecule of RNA called bantam was directly interacting with the machinery responsible for cell growth. The level of bantam in the cell is linked to the amount of activity on the Hippo signalling pathway. 'Bantam is an unusual type of RNA molecule,' explained Mr Thompson. 'Normally RNAs go on to make protein, but bantam is different. Its job is to regulate other RNAs by attaching itself to them.' When bantam attaches itself to them, RNA molecules are unable to make proteins. In this case the proteins would have gone on to shut down cell division, so by preventing their production, bantam effectively promotes cell division. This explains why tissues with high levels of bantam grow too much. Conversely, tissues without bantam grow slowly and remain smaller than normal. The researchers now plan to identify which RNAs bantam docks onto to control.
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