The lighthouse
A RECENT advance concerning a protein molecule called green fluorescent protein (GFP) promises to lead to improved experimental methods. GFP is found in the jellyfish Aequoria victoria and is capable of spontaneous fluorescence: when illuminated by light at a low wavelength, like daylight, it emits green light at a longer wavelength.
The function of GFP in jellyfish remains obscure, but that has not prevented molecular developmental biologists from using the protein. The critical breakthrough was the demonstration by Chalfie and colleagues (in 1994) in the US that GFP's fluorescence could be used as a non-invasive way of labelling cells; more importantly, the label could be followed through the movements, cell divisions and changes of form that accompany embryonic development.
The trick was to engineer a gene of mixed parentage and use it to label (transform) the cell or tissue of choice. The mixed gene will contain signals from the host that permit any gene lying next to it - and that is the gene for GFP - to be decoded. As a result, any cell that contains the mixed gene starts emitting fluorescence.
The idea is simple and effective and has spawned a number of imitations in diverse systems. A recent report by Hodgkinson (Trends in Genetics, August, 1995) from the Medical Research Council's Laboratory of Molecular Biology in Cambridge, UK, states that over 30 laboratories working on one organism alone (the slime mould Dictyostelium) are using GFP. In another experiment, G Gerisch and coworkers of the Max Planck Institute of Biochemistry in Munich, Germany, (Current Biology, November, 1995) have spotted the occurrence of a protein, called coronin, in Dictyostelium. Coronin binds a well-known contractile protein - actin - and possibly has something to do with cell movement; this assumption is now closer to fact.
The researchers transformed Dictyostelium amoebae with a gene that carried the signal for decoding coronin DNA, together with the coroin gene itself followed by the GFP gene. As a result, regions of the cell that had a lot of coronin started glowing. Researchers observed that these highly flourescent portions were precisely where the cell made new movements and established footholds, at the sites of what are called pseudopods. The location of a pseudopod can be changed by giving an appropriate stimulus from the outside. When that is done, the fluorescent patch also changes its location.
Related Content
- Support battery electric trucks in the Delhi EV Policy 2.0
- Order of the National Green Tribunal regarding construction on Yamuna floodplain, Delhi, 19/05/2023
- Decoding digitalization of urban governance in India: policy, people and processes of the smart cities mission and national urban digital mission
- Sustainable industrial development in Punjab, Pakistan
- Rising sea levels threatening historic lighthouses
- A path to prosperity: renewable energy for Islands