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Biology LibreTexts

D. Binding and the Control of Gene Transcription

Skills to Develop

  • describe general mechanisms of how a gene for a given protein might be negatively and positively regulated at the level of gene transcription;
  • describe the structure/function/role of promoters, response elements, RNA polymerase, transcription factors, nucleosomes, histone proteins, epigenetic modifications of DNA in gene transcription;
  • explain the differences (structural, Kds) between specific and nonspecific binding of a ligand to a macromolecule, at the structural level;
  • describe the structural features of both proteins and DNA that result in specific and nonspecific binding;
  • describe and give examples of how post-translational modifications of proteins and epigenetic modifications of DNA can alter gene expression;
  • explain how the apparent Kd for a protein binding to DNA can be altered by the presence of another protein bound to DNA at a proximal site
  • describe the basis of RNA interference in gene expression

One of the central questions of modern biology is what controls gene expression. As we have previously described, genes must be "turned on" at the right time, in the right cell. To a first approximation, all the cells in an organism contain the same DNA (with the exception of germ cells and immune cells). Cell type is determined by what genes are expressed at a given time. Likewise, cells can change (differentiate) into different types of cells by altering the expression of genes. The central dogma of biology describes how genes are first transcribed to messenger RNA (mRNA), and then the mRNA is translated into a corresponding protein sequence.