Transcript 9/18 - Utexas

•Exam #1 is T 9/23
in class
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Available
M 9/22: 10am-noon,
1:30-2:30pm, and
after 3:30pm.
T 9/23 after 10am
How do
cells
express
genes?
Tbl 12.3
A processed mRNA ready for translation
5’ untranslated
region
3’ untranslated
region
Sometimes
RNA is the
final product.
The ATM repair pathway inhibits RNA
polymerase I transcription in response to
chromosome breaks
Michael Kruhlak, Elizabeth E. Crouch, Marika Orlov, Carolina
Montano, Stanislaw A. Gorski, Andre Nussenzweig, Tom Misteli,
Robert D. Phair & Rafael Casellas
Nature Vol 447 pg 730-734
7 June 2007
How does DNA damage affect transcription?
The ATM repair pathway inhibits RNA
polymerase I transcription in response to
chromosome breaks
Michael Kruhlak, Elizabeth E. Crouch, Marika Orlov, Carolina
Montano, Stanislaw A. Gorski, Andre Nussenzweig, Tom Misteli,
Robert D. Phair & Rafael Casellas
Nature Vol 447 pg 730-734
7 June 2007
rRNA is transcribed by RNA polymerase I
comprised
of rRNA
rDNA and
transcription
of rRNA
rDNA is arranged in
repeated transcription
units
Fig 12.16
Fig 12.16
One
transcript
is then
processed
into the
three major
components
of
ribosomes
How can you measure transcription?
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Fig 1a
DNA damage inhibits rRNA transciption
0 Gy
10 Gy
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Fig 1a
More irradiation leads to less transcription
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Fig 1a
Transcription arrest is transitory
Fig 1b
DNA damage by laser. Only damaged
nucleoli show decreased transcription.
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Fig 1c
What cellular components are involved?
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Ku has been shown in
vitro to inhibit RNA pol
I after DNA damage.
Atm kinase is part of
signal transduction
Fig
following DNA breaks. 2a
Atm must be phosphorylated to mediate the
decrease in transcription
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TIFF (Uncompressed) decompressor
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Fig 2b
Brca1, H2ax, Ku80, and 53bp1 are involved in
DNA repair. Transcription arrest occurs, but
resumption is delayed.
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
Fig 2c
DNA damage arrests rRNA transcription
via ATM
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
Combinations of 3 nucleotides code for each
1 amino acid in a protein.
Fig 13.2
Tbl 13.2
The Genetic
Code:
64 codons
20 amino acids
1 start codon
3 stop codons
Fig 12.1
Translation
involves
different
RNA’s
Protein
• rRNA folds up by
intramolecular base
pairing
Fig 13.16
• Ribosomes are made
of both RNA and
protein
Fig 13.15
• On the ribosome,
the mRNA,
tRNA’s, and
growing
polypeptide come
together
Fig 13.16
• The structure of transfer RNA
Fig 13.12
Fig 13.19
Translation initiation sequences along with
the start codon signals the start of translation
• Translation initiation in
eukaryotes
Fig 13.18
The poly-A tail and 5’
cap are involved in
translation initiation
Tbl 13.2
The Genetic
Code:
64 codons
20 amino acids
1 start codon
3 stop codons
Redundancy in codons means that some
tRNAs bind to the codon via wobble
Fig 13.14
mRNAs are usually translated by multiple
ribosomes simultaneously
In bacteria, transcription and translation occur
simultaneously
Fig 13.22
• Termination of translation
by binding of release
factor (a protein) to the
stop codon
Fig 13.21
• All protein interactions in an organism (C. elegans)
compose the interactome
RNA synthesis
Protein
post-translational
modifications:
activation,
inactivation,
destruction, and
translocation
How do
cells
express
genes?
•Exam #1 is T 9/23
in class
(bring cheat sheet)
Available
M 9/22: 10am-noon,
1:30-2:30pm, and
after 3:30pm.
T 9/23 after 10am