Gene Regulation in Prokaryotes

GENE REGULATION IN PROKARYOTES EUKARYOTES DIFFERS IN IMPORTANT RESPECTS... 

Metal ion homeostasis in prokaryotes has not yet provided a model for regulation in eukaryotes. The mechanisms for gene regulation in prokaryotes are proving to be as variable themselves as the mechanisms of transport. Despite great differences between eukaryotes and prokaryotes, it is still probable that their metal ion homeostasis mechanisms may sometimes be found to be similar. For the present, however, the mechanisms of prokaryotic metal ion regulation sometimes provide first hypotheses for constructing models of eukaryotic metal ion homeostasis. 

Selective regulation of gene expression in prokaryotes allows the organism to respond to changing environmental factors, eg, nutrient availability, by altering the repertoire of proteins it makes. 

We begin by examining the interactions between proteins and DNA that are the key to transcriptional regulation. We next discuss the specific proteins that influence the expression of specific genes, first in prokaryotic and then in eukaryotic cells. Information about posttranscriptional and translational regulation is included in the discussion, where relevant, to provide a more complete overview of the rich complexity of regulatory mechanisms. 

The effects of chromosome structure on gene regulation in eukaryotes have no clear parallel in prokaryotes. In the eukaryotic cell cycle, interphase chromosomes appear, at first viewing, to be dispersed and amorphous (see Figs 12-41, 24-25). Nevertheless, several forms of chromatin can be found along these chromosomes. About 10% of the chromatin in a typical eukaryotic cell is in a more condensed form than the rest of the chromatin. This form, heterochromatin, is transcriptionally inactive. Heterochromatin is generally associated... 

Struhl, K. (1999) Fundamentally different logic of gene regulation in eukaryotes and prokaryotes. Cell 98, 1-4. 

The problem of regulation in prokaryotes such as E. coli is far simpler than in complex eukaryotes because of the smaller number of genes. It seems likely that a system of this complexity (about 3,000 genes) should contain no more than 100-300 regulatory proteins because genes with related functions are often under the control of the same regulatory proteins. 

Chapters 30 and 31 Separate chapters devoted to the regulation of gene expression in prokaryotes and eukaryotes, respectively. 

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