Transcriptional Regulation

(Lodish et al., 2000, Section 10.1, 10.5, 10.7)

Inducers and repressors are molecules that bind protein regulators and modify their actions of positive and negative regulation.

An inducer is a molecule, that when bound to a protein regulator, results in transcription.
A repressor is a molecule, that when bound to a protein regulator, prevents transcription.

Prokaryotic example
Lactose operon revisited (Fig. 10.16).

Eukaryotic mechanisms
Hormone activation (Fig. 10.67).
Signal response systems (Fig. 10.68).

Activators that stimulate the Highly Cooperative assembly of initiation complexes.
    Promoter-proximal sites (Fig. 10.60).
     Model of enhancesome that forms on the beta-interferon enhancer (Fig. 10.48).
   Distant enhancer sites (Fig. 10.61).

Silencing of genes near telomeres
    Yeast mating-type control (Fig. 10.55).
    Model of silencing mechanism at yeast telomeres (Fig 10.57).
    Repressors and activators modify the acetylation of histone tails (Fig. 10.58).

Chromatin-remodeling
DNase-sensitive sites bound by modifying proteins.
Chromatin-remodeling complexeshave helicase activity.

Activity

Quiz

References:
Lodish, H., Berk, A., Zipursky, S.L., Matsudaira, P., Baltimore, D., Darnell, J., 2000, Molecular Cell Biology, 4th Ed., W.H. Freeman and Company, NY, New York. ISBN 0-7167-3136-3.