1. Regulation of Gene Expression
Lecture 16
Regulation of Gene Expression

2. Gene expression: the
process by which a gene’s
DNA sequence is converted
into a gene product – protein (mRNA),
tRNA, or rRNA
Each step in the process
of gene expression can
be regulated

3. DNA is packed
into chromatin

4. Step1: Modifying the
chromatin
structure:
histone acetylation or
methylation

5. Step 2: Regulation of Transcription

7. Promoter/Enhancer function
depends on available
transcription factors:
different cells have different
transcription factors
available

8. Step 3: Post-transcriptional Regulation

9. Step 4: Regulating mRNA stability and Step 5: Regulating Initiation of Translation

10. Step 6: Regulating Protein Stability

11. Genetic changes that make things go awry…..
proto-oncogene: a normal gene
that can become an oncogene
oncogene: a modified gene
that encodes for a protein that
can increase the chance that a
normal cell can become a tumor cell
or convert a tumor cell to a malignant cell

12. ras: GTP-binding protein
-part of the MAPK
pathway (signal
transduction)
-this pathway induces cell
division
p53: DNA binding protein
-holds a cell
at the G1/S or G2/M
boundary
-induces DNA repair
machinery