Transcript Matt Reuter
Changing Times, Changing Paradigms The “Big News” in Genomics, 2003 Matt Reuter BL3300, Introduction to Genomics December 5, 2003 Changing Disciplines Role of RNA in the Central Dogma of Molecular Biology Information Storage in the DNA Double Helix Consequences of Mutation and Cancer RNA Interference Double-Stranded RNA creates an RISC that cleaves complementary RNA strands. microRNA: Introns at Work Some introns form microRNAs that create RNA interference, inhibiting other genes. Active RNA: Antisense Complementary, “antisense,” RNA blocks transcription. Active RNA: Riboswitches and Ribozymes RNA can catalyze reactions like enzymes. RNA can control gene expression through riboswitches. DNA: More than ACGT Chemical additions to the DNA store just as much information as the sequence. Epigenome and Epigenetics Epigenetic information is erased and rewritten frequently. Mighty Methylation! Methyl groups tend to “silence” the DNA, producing low transcription. Transposons Recombining or Imprinting? Epigenetic inheritance: imprinting. Epigenetics and Cancer Less genomic methylation in cancer cells than normal cells. More methylation on key cell process genes. “Cancer genes” are NOT mutated in most cancer cells; they are methylated and epigenetically silenced though. Cancer: Massive Mutations or Nuclear Nonsense? Old Theory: Cancer cells have mutations to “cancer genes” that cause cells to reproduce uncontrollably. New Observation: Cancer cells are aneuploid. Most cancer cells would be classified as a separate SPECIES from the normal cells. Is it a bird? A plane? No, it’s CANCERMAN! CELLULAR SUPERPOWERS Ignore “Divide Now” Signals Ignore Neighbor’s “Stop Dividing” Signals Evade Cellular Auto-Destruct Redirect Blood Flow Immortalize Genome Invade Healthy Tissues Carcinogens and Darwin: Survival of the Apathetic “Survival of the Fittest” Carcinogens speed up mutation rates Carcinogens damage cells Normal cells repair Cancer cells divide Strength in Numbers Old Paradigms Yield Control to New Ideas Central Dogma of Molecular Biology Role of RNA Informational Storage in DNA Tumor-Suppressor and Oncogene Theory for the Formation of Tumors. Want to Know More? Gibbs, W. Wayt. “Unseen Genome, The: Beyond DNA.” Scientific American December 2003: 106-113. Gibbs, W. Wayt. “Unseen Genome, The: Gems Among the Junk.” Scientific American November 2003: 46-53. Gibbs, W. Wayt. “Untangling the Roots of Cancer.” Scientific American July 2003: 56-65. Lau, Nelson C. and David P. Bartel. “Censors of the Genome.” Scientific American August 2003: 34-41. All the other great articles in Scientific American are highly recommended!