1. Control of Gene Expression
Chapter 16
Genes and Development

2. Proteins can determine the DNA sequence by binding the major groove of DNA.
Proteins binding the minor groove cannot determine the exact sequence of bases.

5. Prokaryotic gene regulation
Lac Operon

8. Prokaryotic gene regulation
Trp Operon
Biosynthesis of the amino acid typtophan
Therefore, the regulation is the opposite of the lac operon.

10. Eukaryotic gene regulation

12. Enhancer (DNA sequence)
Looping
Activator (protein)

16. Pi ATP ADP + ATP -dependent remodeling factor 1. Nucleosome sliding
2. Remodeled nucleosome
3. Nucleosome displacement
4. Histone replacement

18. RNA Polymerase II
RNA Polymerase II
microRNA gene
microRNA gene
Pri-microRNA
Pri-microRNA
Nucleus
Nucleus
Drosha
Pre-microRNA
Pre-microRNA
Drosha
Exportin 5
Exportin 5
Cytoplasm
Dicer
Mature miRNA
RISC
mRNA
RISC
mRNA cleavage
mRNA
RISC
RISC
Inhibition of translation

19. Exogenous dsRNA, transposon, virus
Repeated cutting
by dicer P P P P P
siRNAs P P P
siRNA
in RISC
Ago +
Ago
RISC
RISC
mRNA
Cleavage of target mRNA

21. Primary RNA transcript Mature RNA transcipt
RNA polymerase II
1. Initiation of
transcription
Most control of
gene expression
is achieved
by regulating
the frequency
of transcription
initiation.
Cut
intron
2. RNA splicing
Gene expression
can be controlled
by altering the
rate of splicing in
eukaryotes.
Alternative splicing
can produce
multiple mRNAs
from one gene.
DNA 3´
3´ poly-A tail
5´ cap 5´
Primary RNA transcript
Exons
Introns
Mature RNA transcipt

22. 3. Passage through the nuclear membrane Gene expression
Large
subunit
3. Passage through
the nuclear
membrane
Gene expression
can be regulated
by controlling
access to or
efficiency of
transport channels.
3´ poly-A tail
Nuclear
pore
mRNA
5´ cap
Small
subunit
4. Protein synthesis
Many proteins take
part in the
translation process,
and regulation
of the availability
of any of them alters
the rate of gene
expression by
speeding or slowing
protein synthesis. 3´ 5´

23. Completed
polypeptide
chain
6. Posttranslational
modification
Phosphorylation
or other chemical
modifications can
alter the activity
of a protein after
it is produced.
5. RNA interference
Gene expression
is regulated by
small RNAs. Protein
complexes
containing siRNA
and miRNA target
specific mRNAs for
destruction or inhibit
their translation. P
RISC P