{"id":12443,"date":"2018-02-22T20:00:07","date_gmt":"2018-02-22T19:00:07","guid":{"rendered":"https:\/\/news.embl.de\/?p=12443"},"modified":"2024-03-23T21:49:23","modified_gmt":"2024-03-23T20:49:23","slug":"loops-loops-loops-dna-gets-organised","status":"publish","type":"post","link":"https:\/\/www.embl.org\/news\/science\/loops-loops-loops-dna-gets-organised\/","title":{"rendered":"Loops, loops and loops: how DNA gets organised"},"content":{"rendered":"\n

Living cells neatly package a big jumble of DNA, over two meters in length, into tidy, tiny chromosomes while preparing for cell division. Scientists have puzzled for decades over how this works. Researchers from Delft University and EMBL have finally managed to isolate and film the process, and witnessed – in real time – how a single protein complex called condensin reels in DNA to extrude a loop. By extruding many such loops in long strands of DNA, the cell packs its genome so it can be distributed evenly between its two daughter cells. The scientists published their findings online in Science<\/em> on 22 February.<\/p>\n\n\n\n

Spaghetti<\/h2>\n\n\n\n

This major discovery finally resolves a question that has been discussed in biology for over a century: how does the cell organise its spaghetti jumble of DNA into neat chromosomes in order be able to distribute its DNA evenly between two daughter cells? For many years, it has been clear that a protein complex called \u2018condensin\u2019 plays a key role, but until now, biologists were divided on exactly how condensin functioned. One theory stated that condensin works like a hook that can grasp and connect DNA within the jumble of DNA, thus tying it together. Another theory suggested that the ring-shaped condensin pulls the DNA inwards to create a loop.<\/p>\n\n\n\n

Scientists from the Cees Dekker group<\/a> at the Kavli Institute of Delft University<\/a>, together with scientists from the group of Christian Haering<\/a> at EMBL Heidelberg who established the purification and fluorescence labelling of the protein, have now managed to catch the condensin complex in the act of extruding a loop of DNA.<\/p>\n\n\n\n

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