more regulating gene expression

1
more regulating gene expression
2

• Gene Expression is controlled at all of these
  steps
• DNA packaging
• Transcription
• RNA processing and transport
• RNA degradation
• Translation
• Post-translational

Fig 15.1
Fig 16.1
3

• Gene Expression is controlled at all of these
  steps
• DNA packaging
• Transcription
• RNA processing and transport
• RNA degradation
• Translation
• Post-translational

Fig 15.1
Fig 16.1
4
Fig 23.25
Alternate Splicing in Drosophila Sex Determination
5
Fig 23.25
Alternate splicing leads to sex determination in
fruit flies
6
mRNA transport is an important regulatory step
Molecular Biology of the Cell 4th ed. Alberts et
al. Fig 6.40 http//www.ncbi.nlm.nih.gov/books/bv
.fcgi?ridmboc4.TOCdepth2
7
mRNA can be localized to a specific parts of a
cell (from Drosophila embryo)
Molecular Biology of the Cell 4th ed. Alberts et
al. Fig 7.52 http//www.ncbi.nlm.nih.gov/books/bv
.fcgi?ridmboc4.TOCdepth2
8
At least 3 mechanisms are involved
Molecular Biology of the Cell 4th ed. Alberts et
al. Fig 7.98
Directed transport via cytoskeleton
Random diffusion and trapping
Degradation and local protection
9
A processed mRNA ready for translation
5 untranslatedregion
3 untranslatedregion
Protects from degradation/ recognition for
ribosome
Protects from degradation/ transport to cytoplasm
10
mRNA with 3 UTR properly localized
mRNA without 3 UTR improperly localized
Molecular Biology of the Cell 4th ed. Alberts et
al. Fig 7.99 http//www.ncbi.nlm.nih.gov/books/bv
.fcgi?ridmboc4.TOCdepth2
11

• Gene Expression is controlled at all of these
  steps
• DNA packaging
• Transcription
• RNA processing and transport
• RNA degradation
• Translation
• Post-translational

Fig 15.1
Fig 16.1
12

• Gene Expression is controlled at all of these
  steps
• DNA packaging
• Transcription
• RNA processing and transport
• RNA degradation
• Translation
• Post-translational

Fig 15.1
Fig 16.1
13
Fig 15.25
Regulation of iron assimilation in
mammals Regulating of Translation
14
Fig 15.26
Ferritin is regulated at translation
15
C. elegans is commonly used to study development
16
C. elegans development
17
C. elegans mutants with cells that do not develop
properly.
18
C. elegans mutants with cells that do not develop
properly. The product of these genes was found
to be RNA?
19
MicroRNAs (miRNA) are 22nt RNAs that play
important regulatory roles
Cell vol. 116, 281-297 2004
20
miRNA expressed
How do microRNAs control gene expression?
miRNA processed to 22nt RNA
Mature miRNA
Fig 15.23 and
21
A processed mRNA ready for translation microRNAs
inhibit translation by binding to the 3 end of
mRNA
microRNA bind to 3-UTR
5-UTR
3-UTR
22
miRNA expressed
the 3 end with attached microRNA interacts with
the 5 end, blocking translation
miRNA processed to 22nt RNA
Mature miRNA
Fig 15.23 and
23
miRNAs can lead to methylation of DNA that leads
to inhibition of transcription
24
microRNAs primarily target gene products that
function during development
Tbl 1
25
tissue specific expression of mouse microRNA
PNAS vol. 101 1 pg 360-365, 2004
26

• Gene Expression is controlled at all of these
  steps
• DNA packaging
• Transcription
• RNA processing and transport
• RNA degradation
• Translation
• Post-translational

Fig 16.1
27
Phosphorylation and dephosphorylation of proteins
can change activity
28
Ubiquitinization targets proteins for degradation
29
Some proteins function in the cytoplasm others
need to be transported to various organelles.
30
How can proteins be delivered to their
appropriate destinations?
31
Fig 13.23
Proteins are directed to their destinations via
signals in the amino acid sequence
32
Protein Destinations secretion or membrane
33

• Signal sequences target proteins for secretion

34
Translation of secreted proteins
35
Translation of membrane bound proteins
36
Translation of secreted or membrane bound proteins
This step determines secretion or membrane bound.
37
Protein Destinations nucleus
Signal anywhere in protein, Translation in
cytoplasm, Signal not removed
38
Protein Destinations mitochondria or chloroplast
Signal translated first, Translation in
cytoplasm, Signal removed
39
Protein Destinations signals in protein
determine destination
Tbl 13.8
40
Next Development- differentiating cells to
become an organism