`Glowing` plant cells that could control cell growth

London: Researchers have genetically inserted proteins from plants into mammalian cells, which glow when exposed to blue light - resulting in a novel ``on-off switch`` that could be used to control cell growth or death.

It could also be useful in growing new tissue or deliver doses of medication directly to diseased cells.

Chandra Tucker of the Duke University and colleagues created the switch using two proteins from a mustard plant, Arabidopsis thaliana, and injected them into yeast cells, kidney cells and cultured rodent brain tissue.

The two proteins interact under light to provide the control over cell functions.

The blue-light switch doesn`t need any additional chemicals to work because it uses a cofactor that naturally exists in non-plant organisms.

"It`s hard to deliver a chemical to a fly or to individual cells. This new approach, with one of the molecules already in the mammalian or yeast cells, makes building a light-controlled switch a lot easier," Nature quoted Tucker as saying.

To test the switch, the team fused one of the light-sensitive Arabidopsis proteins to a red fluorescent protein and the other to a green fluorescent protein, which was in turn attached to the cell membrane.

When the researchers flashed blue light on the cell, the plant proteins interacted, causing the red fluorescent protein to rapidly move to the cell membrane, which then glowed yellow due to the merging of the red and green fluorescing proteins.

The team found that this interaction was reversible and could be triggered repeatedly with light exposure.

The approach is expected to be applicable not only for studies in cultured cells and yeast, but also worms, fruit flies, mice and other model organisms.

Eventually this method could allow researchers to test how cells in a tissue affect neighbouring cells in a tissue, to guide axon growth in neurons to repair brain tissue, or even to kill cancer cells.