RNA

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RNA

• Review for Lecture P131

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NO LAB REPORT FOR NEXT WEEK

• Test 2 in lab next week
• Written or emailed request to switch labs
• Help session 4-530 pm Tuesday with Adriana

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most important concept

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• DNA -gtmore DNA --gt RNA -gt protein

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TODAY

• Transcription
• CD activity 13.1
• post-transcription intron excision
• Translation CD activity 13.2
• Post-translational folding and transport
• other goodies if we have time

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Transcription synthesisof RNA
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Control of Transcription

• Turning on one gene at a time
• Remember E2F, the factor which turns on the gene
  for the S-phase proteins in the cell cycle?
• Many similar examples

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Post-transcriptionsometimes RNA modifications

• Introns
• exons
• spliceosomes controlled by RNA enzymes. Remember
  Freemans RNA world ideas?

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introns
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• fragile X syndrome and diced siRNA
  http//www.eurekalert.org/pub_releases/2002-09/csh
  l-nii091702.php
• Fragile X syndrome is the most common form of
  hereditary mental retardation, affecting 1 in
  4000 males and 1 in 8000 females. Fragile X
  syndrome is the result of a genetic mutation at
  one end of the fragile X mental retardation 1
  gene (FMR1) that causes the abnormal inactivation
  of the gene. It is known that the protein encoded
  by FMR1 -- the so-called fragile X mental
  retardation protein (FMRP) -- binds to RNA and is
  thought to regulate the expression of specific
  genes during neural development, but the mode of
  FMRP action in cells is yet to be defined. This
  work provides some important clues.
• Using Drosophila as a model organism, Drs. Siomi
  and Hannon and colleagues found that FMRP
  associates with RNAi-related cellular machinery.
  RNAi-induced gene silencing depends upon the
  introduction of double-stranded RNA, which is
  processed by Dicer enzymes into short pieces of
  double-stranded RNA. These short interfering
  RNAs, or siRNAs as they are known, are
  incorporated into an RNAi-induced silencing
  complex (RISC), which uses them as a guide to
  target and destroy complementary mRNAs, and
  thereby prevent synthesis of the encoded protein.
  

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TRANSLATION

• Protein synthesis

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• mRNA
• Ribosome sub-units
• tRNA

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tRNA(old version)
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translation

• After initiation, then elongation
• think aboutprocesses,not jargon

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translation

• During elongation, the protein may grow into
  the rER. Remember the take-home part of the last
  test?
• At end of elongation.. Termination. Everything
  falls apart when the stop codon appears.

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Who cares about ribosomes?

• Public Release 30-Sep-2002 Nature Structural
  BiologyMolecular machine could develop drugs for
  bioweapons victimsResearchers at the Department
  of Energy's Los Alamos National Laboratory have
  created the first computer model of a key part of
  the E-coli ribosome, a cellular structure
  responsible for the creation of proteins, that
  has applications in the development of new and
  powerful antibiotics for use in the treatment of
  illnesses caused by all pathogens, including a
  host of bioweapons agents.

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tRNA
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most important concept

•      
• DNA -gtmore DNA --gt RNA -gt protein

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