Cut and Paste

Parasites are closer than we might wish. Harboured by mammals, cats in particular, Toxoplasma gondii could be encountered when cleaning the cat’s litter tray or by eating raw meat. These stowaways are only dangerous to those with weak immunity and unborn babies, but studying them can help reveal the secrets of their more threatening malaria-causing cousins. Toxoplasma cannot survive alone, invading and living inside cells of unsuspecting hosts. Their break-and-enter techniques include molecular grappling hooks, cell-piercing proteins and miniature propelling motors. Researchers created Toxoplasma containing DNA-crafting ‘scissors and glue’, known as recombinases, which cut out and replace certain genes. Successfully removing a motor in this way proved that Toxoplasma could invade without it. The group of motor-lacking Toxoplasma pictured are a normal shape; the remaining pink-stained invasion equipment is seen at their tips.

Written by Claire Worrall

Claire Worrall

Writer

After a degree in natural sciences from Cambridge University, Claire completed her PhD at Newcastle before starting her postdoc at the Karolinska Institute in Sweden.

• Markus Meissner
• University of Glasgow, UK
• Reprinted by permission from Macmillan Publishers Ltd: Nature Methods Copyright 2013
• Published in Nature Methods 10: 125–127