Regulation of Gene Expression at the Translational Level in Plant Embryo
In barley embryos certain mRNAs are synthesized during embryogenesis and stored to be utilized during germination. This kind of temporal separation of transcription and translation involves a fine regulation at the level of translation. In our attempt to understand the regulation of translation of stored messages, we have isolated translation inhibitors (protein and RNA) from barley embryos. The presence of these translational inhibitors could be the reason for inefficiency of the barley embryo cell-free translation system, in spite of the presence of stable translatable mRNA, large store of eukaryotic initiation factor-2 (a rate limiting initiation factor of protein synthesis), ribosomes and other components of translational machinery. Protein inhibitor is a cAMP-independent protein kinase which resembles mammalian casein kinase II. A protein of molecular weight of 52,000, isolated from barley extract by using purified protein kinase-immobilized column, serves as much better substrate than exogenous substrates. Antibodies against protein kinase have been raised to study the molecular mechanism of inhibition. RNA inhibitor is a small weight species (smaller than tRNA) that inhibits initiation of translation. It is a single stranded RNA with no long poly(A) sequence. In the light of the above findings, regulation of gene expression at the translational level in plant embryo is discussed.
KeywordsTranslational Inhibitor Cyanogen Bromide Rabbit Reticulocyte Lysate Barley Embryo Plant Embryo
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- 5.S. K. Sopory, M. Puri Avinashi, N. Deka, and A. Datta, Plant Cell Physiol. 21:649–657 (1980).Google Scholar
- 8.S. Gunnery, A. S. N. Reddy, and A. Datta, Plant Cell Physiol. 24:565–568 (1983).Google Scholar
- 11.A. S. N. Reddy, S. Gunnery, and A. Datta, Biochem. Int. 7:9–13 (1983).Google Scholar
- 14.W. Thornberg and T. J. Lindell, J. Biol. Chem. 252:6660–6665 (1977).Google Scholar
- 15.A. S. N. Reddy and A. Datta, Biochem. Int. 9:77–82 (1984).Google Scholar
- 18.J. S. Garvery, N. E. Cremer, and D. H. Sussdorf, in: “Methods Immunology, 3rd Edition,” (1977), pp. 313-327.Google Scholar