Download Chapter 17 - Gene Regulation in Eukaryotes

Chapter 17
Gene Regulation in Eukaryotes
Study Outline
1. Regulatory transcription factors
a. Structural features of regulatory transcription factors allow them to bind to DNA
b. Regulatory transcription factors recognize regulatory elements that function as enhancers
or silencers
c. Regulatory transcription factors may exert their effects through TFIID and mediator
d. The function of regulatory transcription factor proteins can be modulated in three ways
e. Steroid hormones exert their effects by binding to a regulatory transcription factor
2. Chromatin remodeling, histone variation, and histone modification
a. Chromatin remodeling complexes alter the positions and compositions of nucleosomes
b. Histone variants play specialized roles in chromatin structure and function
c. The histone code also controls gene transcription
d. Eukaryotic genes are flanked by nucleosome-free regions and well-positioned
nucleosomes
e. Transcriptional activation involves changes in nucleosome locations, composition, and
histone modifications
3. DNA methylation
a. DNA methylation occurs on the cytosine base and usually inhibits gene transcriptoin
b. DNA methylation is heritable
4. Insulators
a. Insulators may act as a barrier to changes in chromatin structure or block the effects of
neighboring enhancers
b. Insulators may promote the formation of loops that block the effects of nearby enhancers
5. Regulation of RNA processing, RNA stability, and translation
a. Alternative splicing regulates which exons occur in an RNA transcript, allowing different
polypeptides to be made from the same structural gene
b. The stability of mRNA influences mRNA concentration
c. Double-stranded RNA can silence the expression of mRNA
d. Fire and Mello show that double-stranded RNA is more potent than antisense RNA at
silencing mRNA
e. RNA interference is mediated by microRNAs or short-interfering RNAs via the RNAinduced silencing complex
f. The regulation of iron assimilation is an example of the regulatory effect of RNA-binding
proteins on translation