11 April 2014
These scanning electron micrographs show the two faces of the Hippo pathway – a series of proteins that control organ growth, stem cell function and tumour development. Here, the unsightly fruit fly (right) is covered in patches of cells containing a mutation in the Hippo gene encoding a key protein of the cascade. This causes the fly’s cuticle to grow uncontrollably giving it a hippopotamus-like appearance. The other fly has a normal gene and looks dandy. Defects in the Hippo pathway contribute to the development of cancer. But confusingly, when certain parts of the pathway are activated it has a beneficial role, stimulating tissue repair and regeneration after injury. Scientists hope that targeting components of the Hippo pathway with novel drugs will provide exciting new approaches for cancer treatment.
Written by Nick Kennedy
Image courtesy of Georg Halder and Randy Johnson
VIB Research Institute, Flanders, Belgium
Adapted by permission from The Company of Biologists Ltd
Research published in Nature Reviews Drug Discovery, December 2013
17 April 2014
Splitting the Egg
We start life as a single cell, created when dad’s sperm meets mum’s egg cell. The fertilised egg has a complete set of DNA, half from mum and half from dad. In order to create eggs and sperm that carry only half a set of DNA, specialised germ cells go through a process called meiosis. Here, a female mouse germ cell is in the final stage of meiosis. Shown in pink, the DNA is about to be divided to create a large egg cell and a much smaller cell called a polar body, which sticks to the side of the egg and plays no part in making a baby. This uneven division ensures that the cell destined to be the egg gets the biggest share of nutrients, to fuel the early stages of development. Researchers are studying how this process is controlled, to gain insights into the earliest stages of life.
Written by Kat Arney