Genetics: From Genes to Genomes

Outline of Chapter 17• There are many steps in gene expression and regulationcan occur at any one of them.• Genetic and molecular studies show that most regulationaffects the initiation of RNA transcripts.• Studies of genes for lactose utilization• Negative regulation – blocks transcription• Positive regulation – increases transcription• DNA binding proteins acting on RNA polymerase at promoter are mainagents of regulation• Attenuation of expression – tryptophan pathway• Gene expression is fine tuned by premature termination oftranscription.Copyright © The McGraw-Hill Companies, Inc. Permission required to reproduce or display17-3