Molecular Biology: Gene Regulation

Transcriptional Regulation

• Transcription factors: Proteins that bind to specific DNA sequences to regulate gene expression
• Enhancers: DNA sequences that loop back to the promoter to increase transcription
• Promoters: DNA sequences that recruit RNA polymerase to initiate transcription
• Repressors: Transcription factors that inhibit gene expression by binding to operators

Epigenetic Regulation

• DNA methylation: Addition of methyl groups to CpG islands, typically leading to gene silencing
• Histone modification: Covalent modification of histone proteins to alter chromatin structure and accessibility
• Chromatin remodeling: ATP-dependent alteration of chromatin structure to facilitate or inhibit transcription

Post-Transcriptional Regulation

• RNA splicing: Removal of introns and joining of exons to form mature mRNA
• Alternative splicing: Generation of different mRNA isoforms from a single gene
• MicroRNAs (miRNAs): Small RNAs that bind to mRNA, preventing translation
• RNA-binding proteins (RBPs): Proteins that regulate mRNA stability, localization, and translation

Gene Silencing

• RNA interference (RNAi): Double-stranded RNA-mediated degradation of specific mRNA molecules
• Gene silencing by siRNAs: Small interfering RNAs that target specific mRNAs for degradation
• Epigenetic gene silencing: Heritable silencing of gene expression through epigenetic modifications

Cellular Regulation

• Cell signaling: Signaling pathways that regulate gene expression in response to environmental cues
• Hormone regulation: Hormones that regulate gene expression by binding to specific receptors
• Tissue-specific gene expression: Regulation of gene expression in specific cell types or tissues