A technique for visualizing specific sugars in living worms which provides insight into their biological function is published online this week in Nature Methods.
Visualization of non-genetically encoded molecules, such as sugars or lipids, within living organisms is challenging but important to understand the essential role these molecules play in development and disease. In the past scientists have used chemical compounds to attach a fluorescent dye to sugars, but this is a non-specific approach since it labels all sugars, irrespective of their modifications.
Hannes Bulow and his colleagues are especially interested in such modified sugars, particularly in heparan sulfates - linear polysaccharides displayed on the outside of a cell whose modification pattern determines their biological function. To follow particular heparan sulfates through the course of a worm’s development, the authors fused antibodies, that recognize the specific modifications on the sugar, to GFP (Green fluorescent protein) together with a secretion signal that ensured export of the antibodies to the outside of the cell where they bound their targets. The scientists identified the cell types that displayed the heparan sulfates at each key developmental stage.
This approach has the potential to easily be extended to other sugars, lipids or proteins with post translational modifications as long as specific antibodies for the modification exist.