The genome of both prokaryotes and eukaryotes is made up of genes. These genes are expressed to produce functional molecules such as RNA and proteins, which are vital for the functioning of the cell. The two steps of gene expression are transcription and translation. Both transcription and translation of prokaryotes and eukaryotes are very similar. However, some advanced features can be identified in eukaryotic gene expression as eukaryotes are more developed organisms when compared to prokaryotes. However, both types of organisms use several mechanisms for the regulation of their gene expression as well. Generally, prokaryotic gene expression is regulated at transcriptional level while eukaryotic gene expression is regulated in both transcriptional and translational levels.
Key Areas Covered
1. How is Gene Expression Regulated in Prokaryotes and Eukaryotes
– Definition, Regulation of Gene Expression
2. How is Gene Regulation in Prokaryotes and Eukaryotes Similar
– Similarities Between Gene Regulation in Prokaryotes and Eukaryotes
Key Terms: Eukaryotes, Gene Expression, Prokaryotes, Regulation of Gene Expression, Transcription, Translation
How is Gene Expression Regulated in Prokaryotes and Eukaryotes
Gene expression is the process of transcription of DNA into RNA, followed by translation into proteins. It is a tightly regulated process in both prokaryotes and eukaryotes. The regulation of gene expression is involved in the production of either increased or decreased amount of gene products. A wide range of mechanisms is involved in the regulation of gene expression.
- Replication level – Mutations may cause alterations of the gene expression.
- Transcriptional level – Activators and repressors regulate the transcription.
- Post-transcriptional level – RNA splicing is involved in the regulation of gene expression at post-transcriptional level.
- Translational level – The translation of a mRNA molecule into an amino acid sequence of a protein is controlled by various processes such as RNA interference pathway.
- Post-translational level – The synthesis of a protein can be regulated by controlling the post-translational modifications.
Different levels of regulation of gene expression are shown in figure 1.
How is Gene Regulation in Prokaryotes and Eukaryotes Similar
The transcription and translation are very much similar in both prokaryotes and eukaryotes. RNA polymerase is involved in the process of transcription of genes into mRNA. Translation of both prokaryotes and eukaryotes occurs in the cytoplasm with the help of ribosomes. The regulation of gene expression in both prokaryotes and eukaryotes shows some similarities.
- Regulation at the transcriptional level – The regulation of gene expression in prokaryotes mainly occurs during the initiation of transcription. The gene expression is regulated at the transcriptional level in eukaryotes as well.
- Transcription factors – The binding of RNA into the promoter region is regulated by transcription factors in both prokaryotic and eukaryotic gene expression.
- Structural genes – Functionally similar prokaryotic genes are organized into gene clusters known as operons. In eukaryotes, multiple proteins are produced by alternative RNA splicing.
- Activators and repressors – Activators positively-regulate the gene expression while repressors negatively-regulate the gene expression in both prokaryotes and eukaryotes.
- Feedback Mechanisms – Both prokaryotic and eukaryotic gene expression is regulated by feedback mechanisms.
Regulation of prokaryotic gene expression at the transcriptional level is shown in figure 2.
However, in eukaryotes, the regulation of gene expression occurs in various stages throughout the process of gene expression. It is regulated in post-transcriptional, translational, and post-translational levels.
Gene expression is the mechanism of synthesizing functional RNA or protein molecules inside the cells. Gene expression mechanism is very similar in both prokaryotes and eukaryotes. Gene expression should be regulated in order to synthesize the required amount of gene products by the cell. In both prokaryotes and eukaryotes, the gene expression is regulated at the transcriptional level. Both mechanisms are controlled by transcription factors, activators, and repressors. Both prokaryotic and eukaryotic genes can be regulated to produce multiple gene products.
1. “Regulation of Gene Expression.” Lumen, Boundless Biology, Available here