1. Control of Gene Expression in Eukaryotic cells
BSCI 420 Lecture 11A Sept. 2002
“How may deaths will it take till we know that to many
people have died?”
-Bob Dylan
1. Overview
2. Regulation of individual genes
A. Cis-acting regulatory sequences
B. Trans-acting (Transcription) factors
3. Regulation of chromatin domains

2. 1. Overview
All Cells of your body (with a few exceptions) contain the
same DNA.
So how do different cells become different?
By regulating gene expression at many different levels:
a. Structure of chromatin domains
b. Transcription of individual genes
c. Processing of RNA transcripts
d. Transport vs. degradation of messages
e. Translation vs. storage or degradation of messages
f. Activation of proteins
g. Degradation of proteins

3. Summary
of gene
expression
in eukaryotes
7. Degraded
protein

4. The first and major level of control is transcriptional.
Transcriptional control occurs at 2 levels:
At the level of A. Individual genes -or- B. Chromatin domains
Individual gene regulation occurs by the the interaction of:
1. Cis-acting regulatory sequences on DNA and
2. Trans-acting transcription factors
a) Promoters are:
1) A DNA sequence where RNA polymerase binds to the DNA without transcribing it.
2) Just upstream from the transcribed sequence
3) Unidirectional - They orient RNA polymerase in one direction and send it toward the coding region of the gene

5. RNA polymerase

6. Initiation of transcription at a eukaryotic promoter