6.5 Regulation of Gene Expression

• Regulatory sequences are regions of DNA that control gene expression by turning genes "on" or "off"
• Regulatory sequences interact with specific proteins to activate or repress transcription
• Regulatory sequences are often located near or within the promoter regions of genes
• Types of regulatory sequences include enhancers, silencers, promoters, and terminators
• Enhancers increase the level of transcription of a gene, while silencers decrease it
• Promoters provide the binding site for RNA polymerase and other initiation factors
• Terminators signal the end of transcription
• Transcription factors, also known as proteins, bind to specific DNA sequences and control the rate of transcription
• Transcription factors can activate or repress transcription by recruiting or inhibiting RNA polymerase binding
• Transcription factors work with proteins to ensure genes are expressed at the appropriate time and level
• Dysregulation of transcription factors and proteins can lead to diseases, including cancer
• Epigenetics refers to heritable changes in gene function without changes to the DNA sequence
• Epigenetic modifications can affect gene expression by influencing DNA accessibility to transcription machinery
• Epigenetic modifications can occur on DNA (methylation) and histones (acetylation, methylation)
• Epigenetic modifications can be inherited or influenced by environmental factors
• Understanding epigenetic regulation is crucial for developing therapeutic strategies for diseases
• The phenotype of a cell or organism is determined by the genes expressed and their levels
• Different cell types express specific genes for their distinct functions and characteristics
• Gene expression is regulated by transcriptional regulation, inducers, and repressors
• During development, genes are expressed sequentially, controlled by a network of transcription factors
• Master regulators like homeobox genes control body part development during embryonic development
• Prokaryotes and eukaryotes have groups of genes that are coordinately regulated
• In prokaryotes, operons are groups of genes transcribed in a single mRNA molecule
• Prokaryotic operons are controlled by a single promoter and regulated by repressor proteins
• Eukaryotic genes may be influenced by the same transcription factors for coordinated regulation
• Understanding coordinated gene regulation is important for cellular processes and responses to stimuli