Lecture 3, Part2 Gene transcription. Promoters, Enhancers, sigma Factors.

In this part of the lecture, we compare transcription in prokaryotes and eukaryotes. We examine how RNA polymerase works, where it interacts with DNA, and the precise mechanisms of these interactions. We explore the structure and function of promoters and enhancers. Finally, we contrast the elegant transcription strategies that prokaryotes and eukaryotes use to manage and optimize transcription: prokaryotes solve specificity with one core enzyme plus multiple interchangeable sigma factors, whereas eukaryotes invest in three specialized nuclear RNA polymerases, each with its own dedicated machinery for rRNA, mRNA, or tRNA synthesis.