Toward an Understanding of Gene Expression in Plants

Abstract

Gene expression results from a complex series of biochemical steps that include: (1) transcription of the DNA; (2) processing of the RNA transcript into its final form and transport from the nucleus to the cytoplasm; (3) translation of the RNA (in the case of the messenger RNAs) to produce a protein product; (4) post-translational modification of the protein product. Factors that can modify these processes include those that control the rates of transcription and/or translation, and that control the turnover rate of the transcript or protein. Most research dealing with gene expression in plants includes simply quantitating molecules that result from expression, i.e., RNA, proteins, catalytic reaction products, or rates or transcription and translation. Only recently, with the advent of gene transplantation and genetic engineering experiments, has it been possible to site-direct the mutation of specific DNA sequences as a means to address the fundamental processes that control the expression of genes. The following discussion presents examples of such studies in plant biology which, hopefully, will lead to a better understanding of how plants control the expression of their complex nuclear genome.