Fishing up chromosomes

Researchers at the University of Dundee have made a significant new discovery on how cells behave and protect themselves against cancers and congenital disorders as reported in Nature tomorrow (Thursday April 21).

Dr Tomo Tanaka and his team members at the University’s School of Life Sciences, Drs Kozo Tanaka, Naomi Mukae and Hilary Dewar, in collaboration with Drs Euan James and Alan Prescott and researchers in Germany, have uncovered how cells prepare for the process of chromosome separation.

All human cells, except eggs and sperms, contain 46 chromosomes, all of which carry vital genetic information. Because genetic information is crucial for the proper function of cells for the organs and tissues that they organise, all chromosomes must be precisely copied and separated into two cells, known as the daughter cells, during each cell division. Otherwise cells would die, become transformed into cancer cells, or cause congenital diseases such as Down’s syndrome.

Cells regulate chromosome separation by a network of threads called microtubules. To prepare chromosome separation, the microtubule network must first capture chromosomes. However, how microtubules capture chromosomes has until now been a complete mystery. By visualizing this step in live cells, the research team has successfully analysed the crucial but so-far concealed process.

Dr Tomo Tanaka says “We can liken chromosomes to big fishes that must be caught. To catch the fishes, cells are equipped with sophisticated fishing lines that are called microtubules. Our study discovered which parts of ’fishes’ are hooked up on the ’fishing line’ and how ’fishes’ are pulled in using the ’fishing line’. Very interestingly, the strength of the ’fishing line’ is enhanced only when ’fishes’ are caught on the line. We discovered how cells make this happen. I do not think any grand master of fishing can beat cells in our body, whose ’fishing lines’ or microtubules are never broken when they pull gigantic ’fishes’ out of water.”

The research team believes that this is one of the most crucial steps on how cells assure their chromosome inheritance during their divisions to prevent cell death, cancers and other diseases. The team is currently trying to discover what ’baits’ are used to attract ’big fishes’ towards ’fishing lines’.

Dr Tomo Tanaka is a Wellcome Trust Career Development Fellow and Principal Investigator in the Division of Gene Regulation and Expression based in the Wellcome Trust Biocentre at the University of Dundee’s School of Life Sciences. The research is funded by The Wellcome Trust and Cancer Research UK.