Heat-shock proteins (Hsps) have long been known to perform the vital role of protecting other proteins during periods of stress (i.e. environmental change). In light of recent evidence, however, a specific protein, Hsp90, has been found to help organisms in another, unexpected way: buffering them against genetic change. It does this by masking the effects of new genetic variations. Resistance of organisms to genetic and environmental change has been speculated since the 1940’s and has been termed ‘canalisation’. It was not until experiments involving Drosophila melanogaster and Arabidopsis thaliana that the specific role of Hsp90 in this process was uncovered. A more recent study questions whether Hsp90 is the sole capacitor responsible for protecting organisms against genetic perturbations. It specifically looked at fruit flies’ bristles and wing sizes. These are complex quantitative traits, which had not been tested in previous studies. The study analysed the effects of inhibiting Hsp90 on these traits. The results proved surprising. It was found that genetic canalisation did not solely depend on Hsp90. This raises the possibility that the involvement of Hsp90 in protecting organisms against genetic change is only contributory. Clearly more extensive research is required in order to further elucidate the exact role of Hsp90 in buffering genetic variation.
Picture: A schematic diagram of Hsp90.
References
Pigliucci, M. (2002) Nature, 417, 598-599.
Queitsch, C., Sangster, T. A. and Lindquist, S. (2002) Nature, 417, 618-624.
Rutherford, S. L. and Lindquist, S. (1998) Nature, 396, 336-342.
Stearns, S. C. (2002) Proceedings of the National Academy of Sciences 99, 10229-10230.
Sangster, T. A., Lindquist, S. and Queitsch, C. (2004) BioEssays, 26, 348-362.
Posted by: s41187089
Topic: Directed Mutation (heat-shock proteins)
