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Isolation and Characterization of Cellular Complexes Containing the Histone Deacetylase SIRT1 Vincent Lew Howard Hughes Medical Institute Fellowship Mentor: Dr. Mark Leid Molecular Pharmacology Lab College of Pharmacy - Oregon State University
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DNA Humans have 14,000 to 73,000 micrometers of DNA per chromosome All 46 chromosomes together in a human cell have 2 meters of DNA which is contained in a nucleus that is 5 micrometers in diameter How does it fit?
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History Human Jurkat Cells (Immune System) Silent Information Regulator (SIRT) Histone DeAcetylase Complex (HDAC) Chicken (Ovalbumin Upstream Promoter) Transcription Factor Interacting Proteins 1 & 2 (CTIP1 & CTIP2) Represses Gene Transcription
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Project Aim To isolate Silent Information Regulator (SIRT) protein & complexes via purification To investigate all of the functions of SIRT in the human body Determine by finding what proteins are found with it
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? ? ? SIRT
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Activation RNA Polymerase Acetylation Complex RNA Polymerase
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Repression CTIP / SIRT Complex
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Step One: Phosphocellulose Phosphocellulose Column Tightly packed resin Negatively charged Wash w/ increasing NaCl molarity (stronger washes) IN COLLECT Na+ Cl - Na+ Cl -
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Step Two: Where is the Protein? Electrophoresis Negatively Charged & Migrates to Cathode Smaller strands migrate faster 10% Acrylamide Gel + -
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Step Two Continued Electrotransfer Use of electricity to transfer proteins from acrylamide gel to nitrocellulose membrane 10% Acrylamide Gel Nitrocellulose Membrane
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Step Three: Western Blot Immunoreactivity Use of antibodies that bind to specific proteins nitrocellulose membrane chemiluminescence specific protein
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Western Blot Results Flow Through 300 mM 600 mM What does this mean? There is a significant amount of SIRT protein in the Input & Flow Through Input: originally put into the column (before purification) Flow Through: protein that did not stick to the column Input
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Step Four: DEAE Diethylaminoethyl Column Tightly packed resin Positively charged Wash w/ increasing NaCl molarity (stronger washes) IN COLLECT Na+ Cl - Na+ Cl -
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Western Blot Results Input Flow Through 200 mM 400 mM 600 mM 800 mM 1 M What does this mean? There is SIRT protein in the Input,.2mM &.4mM lanes Input: originally put into the column (before purification).2mM: what eluted after.2 milli-Molar NaCl solution.4mM: what eluted after.4 milli-Molar NaCl solution
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Step Six: Size Exclusion Size Exclusion column Separates based on SIZE of molecules Use of known markers to determine size of unknown molecules Thyroglobulin: 669 kD Catalayse: 232 kD BSA (albumin): 67 kD 1 kiloDalton = 1.67 x 10-24 kg
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IN OUT Size Exclusion
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Western Blot Results Thy (669) Cat (232) BSA (67) Thy (669) Cat (232) 200 mM 400 mM
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Step Seven: Immunoprecipitate Final step of purification in this project Use of specific antibody (Abx) to bind to individual protein complex Extract only that which is bound to antibody
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Immunoprecipitation Protein X Protein Y SIRT SIRT complexed to unknown protein Sir2 Abx Sepharose Beads
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Mass Spectrometry Determine protein structure based on molecular mass
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Results Still to be determined
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Acknowledgements Howard Hughes Medical Institute Dr. Mark Leid – Molecular Pharmacology, Oregon State University Valerie Peterson – Molecular Pharmacology, Oregon State University
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