The Messenger RNAs and Genes Coding for the Small and Large Subunits of Ribulose 1,5-Bisphosphate Carboxylase/Oxygenase in Chlamydomonas reinhardi
The synthesis of ribulose 1,5-bisphosphate (RuBP) carboxylase/oxygenase poses some interesting strategical problems for the plant cell. The enzyme is produced in the cell in great abundance and is sequestered within the chloroplast. It is synthesized by two different protein synthesizing systems, one in the cytoplasm and one in the chloroplast (1–4). To produce large quantities of the enzyme, the cell must synthesize this protein preferentially over all others. This presents gene regulation problems that are aggravated by the enzyme being composed of two different subunits, the small subunit (S) and the large subunit (L), which are apparently encoded by two genomes within the cell (5–7) that may employ quite different means for controlling the synthesis of their gene products. In this paper we describe how Chlamydomonas reinhardi deals with these problems of RuBP carboxylase synthesis. We are not asking why certain plant cells such as C. reinhardi produce so much of this enzyme—that has been the subject of other articles in this Symposium We are concerned only with the mechanisms of how this happens.
KeywordsChloroplast Genome Hybridization Probe Sucrose Density Gradient Lauroyl Sarcosinate RuBP Carboxylase
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- 13.Rosner, A., Reisfeld, A., Jakob, K. M., Gressel, J., and Edelman, M., Colloq. Int. CNRS 261, 561–7 (1977).Google Scholar
- 18.Howell, S. H., Nature London 240, 264–7 (1972).Google Scholar
- 24.Howell, S., Heizmann, P., and Gelvin, S., in Biogenesis of Chloroplasts and Mitochondria, pp. 625–8, T. Bucher et al., Editors, North-Holland, Amsterdam, 1976.Google Scholar