Eukaryotes

• Regulation can be transcriptional or post-transcriptional.
• Eukaryotes are multicellular, so cells differentiate by expressing different genes.
• Transcriptional regulation is the control of the ability of RNA polymerase to access a gene's promoter.
• Post-transcriptional regulation is the control of gene expression that occurs after transcription.
• Chromatin is a complex made up of DNA and proteins that make up chromosomes. DNA is wrapped around histone proteins.
• Histones have tails which can be modified with acetyl groups (activation) or methyl groups (repression).
• Eukaryotic cells can regulate transcription by modifying histone protein tails, which alters chromatin structure.
• Euchromatin is not condensed and DNA is accessible to direct protein synthesis
• Heterochromatin is highly compacted and tightly coiled into a dense mass. It is not accessible for protein synthesis.
• Transcription factor proteins are needed to start transcription in DNA.
• General transcription factors help RNA polymerase bind to the promoter.
• Regulatory transcription factors bind to the enhancer region to recruit general transcription factors
• Alternative splicing and RNA editing is regulation through RNA processing and can lead to the production of different proteins in different cells.
• Small regulatory RNAs (miRNAs and siRNAs) can block translation and are a form of regulation through translation.
• Proteins can activate or block translation initiation through regulation through translation.
• Proteins can be modified or degraded after translation by regulation through post translational modification.