Gene Expression Regulation in Multicellular Organisms — Revision Sheet

1. 📌 Essentials

• Same genome in all cells; different gene expression profiles define cell identity.
• Regulation occurs at DNA, RNA, and protein levels, with transcription as the primary control point.
• Transcription factors bind DNA via α helices in the major groove, recognizing specific motifs.
• Operons in bacteria coordinate multiple genes under control elements.
• Chromatin structure influences gene; modifications include histone acetylation and methylation.
• Enhancers, looping, and Mediator complex facilitate eukaryotic gene regulation.
• Chromosomal loops (TADs) organize enhancer-promoter interactions spatially.
• Master regulators can trigger organ development; cell reprogramming is possible via key transcription factors.
• DNA methylation at CpG sites is inherited and influences development and aging.
• Noncoding RNAs (miRNAs, siRNAs, lncRNAs) regulate gene expression post-transcriptionally and epigenetically.

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