DNA Repair Lehninger, chapters 8 and 25 Blackburn & Gait, Ch. 6 and 8

Slides:

Advertisements

Similar presentations

DNA replication and repair

Advertisements

DNA Repair. -Errors (at a rate of 1x10 -9 ) are introduced during DNA replication -DNA in cells is constantly being altered by cellular constituents,

DNA damage and repair summary

Section F DNA Damage, Repair and Recombination

1 DNA Repair Dr Derakhshandeh. 2 For DNA information must be transmitted intact to daughter cells.

DNA damage & repair.

DNA damage and repair Types of damage Direct reversal of damage Excision repair in prokaryotes and eukaryotes base excision nucleotide excision Nonhomologous.

Repair mechanisms 1. Reversal of damage 2. Excision repair 3. Mismatch repair 4. Recombination repair 5. Error-prone repair 6. Restriction-modification.

Genetic Material-DNA 6 November 2003 Reading:The Cell; Chapter 5, pages:

DNA damage, repair and recombination

Online Counseling Resource YCMOU ELearning Drive… School of Architecture, Science and Technology Yashwantrao Chavan Maharashtra Open University, Nashik.

DNA Repair and Recombiantion. Methyl-directed mismatch repair (1) If any mismatch escapes the proof reading mechanisms it will cause distortion of the.

A summary of spontaneous alterations likely to require DNA repair. The sites on each nucleotide that are known to be modified by spontaneous oxidative.

The Mutability and Repair of DNA

25 February, 2005 Chapter 10 Gene Mutation: Origins and Repair Processes GAATTC  GTATTC A  a.

BME 130 – Genomes Lecture 23 Genome evolution I: Mutations, repair, and recombination.

Karp/CELL & MOLECULAR BIOLOGY 3E

Chapter 20 Repair Systems.

Genetica per Scienze Naturali a.a prof S. Presciuttini Biological repair mechanisms There are many potential threats to the fidelity of DNA replication.

Microbial Genetics (Micr340) Lecture 14 DNA Repair and Mutagenesis.

1 Mutations Mutations are inheritable changes in the DNA –“Failure to faithfully store genetic information” Changes can be to chromosomes or genes –Current.

 MUTAGENESIS  DNA DAMAGE  DNA REPAIR  RECOMBINATION.

The Mutability and Repair of DNA

DNA Damage, Mutations, and Repair See Stryer p

Chapter 16 Mutation, Repair and Recombination.

Biochemistry Sixth Edition Chapter 28 DNA Replication, Repair, and Recombination Part III: DNA repair and recombination Copyright © 2007 by W. H. Freeman.

Gene Mutations.

DNA Repair and Cancer. Genome Instability Science, 26 July 2002, p. 544.

DNA replication and repair - Lecture 3 Jim Borowiec September 28, 2006.

DNA Repair Uracil-DNA Glycosylase. DNA is continually assaulted by damaging agents (oxygen free radicals, ultraviolet light, toxic chemicals). Fortunately,

Mutations and mutagens

18.1 Mutations Are Inherited Alterations in the DNA Sequence.

DNA metabolism Replication Early on - “Template” so molecules can line up in a specific order and be joined to create a new macromolecule 1940s - DNA =

DNA Ligase Energy-dependent joining of the chains Activated by NAD + or ATP hydrolysis NAD  NMN + + AMP ATP  AMP + PP i AMP -attaches to lysine group.

Chapter 18 – Gene Mutations and DNA Repair

Various ways in which DNA damage leads to mutations in proteins Insertion.

Gihan E-H Gawish, MSc, PhD Ass. Professor Molecular Genetics and Clinical Biochemistry KSU 10 TH WEEK DNA damage, repair & Mutagenesis.

1 DNA Repair Dr Derakhshandeh-Peykar, PhD. 2 For DNA information must be transmitted intact to daughter cells.

Lecture 7 DNA repair Chapter 10 Problems 2, 4, 6, 8, 10, 12, and 14

12.6 DNA Repair. DNA Repair Errors in DNA replication or damage to DNA create mutations Errors in DNA replication or damage to DNA create mutations -

Chapter 9 The Mutability and Repair of DNA

MUTAGENS AND MUTAGENESIS. Mutagens  Naturally occurring mutations are referred as spontaneous mutations and are thought to arise through chance errors.

DNA Mutations and Repair Chapter 17. Mutation: is defined as an inherited change in genetic information by cell division or individual organisms. Chernobyl,

GENETICS ESSENTIALS Concepts and Connections SECOND EDITION GENETICS ESSENTIALS Concepts and Connections SECOND EDITION Benjamin A. Pierce © 2013 W. H.

DNA damage and repair. DNA: the genetic material ensuring preservation of the genetic information preservation of the genetic information its transfer.

DNA Repair DNA repair is a system used to correct DNA damage caused by either: 1-Errors during DNA replication including incorrect base-pairing (mismatching)

Repair of Damaged DNA DNA is the only cellular macromolecule that can be repaired DNA damage includes: base modifications nucleotide deletions or insertions.

Gihan E-H Gawish, MSc, PhD Ass. Professor Molecular Genetics and Clinical Biochemistry KSU 10 TH WEEK DNA damage, repair & Mutagenesis.

1.Structures and Functions of Nucleic Acids 2.Organization and Content of Genomes 3.DNA Replication 4.The Mutability and Repair of DNA 5.DNA Recombination.

DNA Repair DNA repair is a system used to correct DNA damage caused by either: A- Errors during DNA replication including incorrect base-pairing (mismatching.

Depurination Release of adenine or guanine bases.

DNA Repair. Although DNA replication occurs under strict control (Proofreading system), errors can yet occur and they need to be corrected, otherwise;

DNA repair Of the thousands of random changes created every day in the DNA of a human cell by heat, metabolic accidents, radiation of various sorts, and.

Chapter 12 DNA STRUCTURE AND REPLICATION. A. DNA Structure DNA is a nucleic acid composed of nucleotide monomers. DNA nucleotide consists of: F one phosphate.

1 Chapter 16 DNA Replication, Repair, and Recombination: The Efficiency of Cellular Chemistry.

Welcome to Class 18 Introductory Biochemistry.

Dr.Aida Fadhel Biawi 2014 Mechanisms of DNA repair.

Genetics NewsGenetics News. Mutation - Overview Mechanism of mutation Spontaneous Induced Duplication/Insertions Mechanism (example: lacI) Fragile X syndrome.

Lecture 3.Mutations and DNA Reparation Myandina Galina Ivanovna professor, Ph.D.,Dr.Sc.

Lecture 18 DNA Repair Rohini. K. Learning Objective 08 Nov 2011Rohini K FoM 2  An overview of the types of DNA damage  DNA repair mechanisms  Defects.

ReactionBasePairingMutationMispairing DeaminationCGUA ATHypoxanthineC DeaminationGCXanthineC AkylationCG5’-methyl C Gene scilencing or A AkylationGCO6-methyl.

DNA damage and repair summary

Variation Mutations DNA repair

DNA damage, repair & Mutagenesis

DNA Mutations and Repair

DNA Mutations and Repair

DNA Mutations and Repair

Mutation Point Mutations Repair of “point” mutations

Presentation transcript:

DNA Repair Lehninger, chapters 8 and 25 Blackburn & Gait, Ch. 6 and 8 Know main types of DNA damage Know repair mechanisms used for each type of damage Know the difference between transition and transversion Understand why defects in repair mechanisms could lead to cancers

DNA metabolism DNA Repair DNA damage from: 1. spontaneous loss of exocyclic amino group (deamination) C  U occurs once every 107 C residues in a day (100x a day) A  G (Hyp) occurs 100x slower 2. Hydrolysis of bond between sugar and base (apurinic residue) Occurs once every 105 purines in a day (10,000x a day) Slower for pyrimidines

DNA metabolism DNA Repair DNA damage from: 3. UV damage causes pyrimidine dimers

DNA metabolism DNA Repair DNA damage from: 4. Reactive chemicals Nitrous acid precursors Alkylating agents (nitrogen mustard, DMS, SAM)

DNA metabolism DNA Repair DNA damage from: 5. Oxidative Damage H2O2, •OH, •O2-

DNA metabolism DNA Damage & Repair

DNA metabolism DNA Repair

DNA metabolism DNA Repair In bacteria

DNA metabolism DNA Repair

DNA metabolism DNA Mismatch Repair Correction of mismatches increases fidelity by 100 to 1000-fold Repairs mismatches up to 1000 bp from hemi-methylated GATC

DNA metabolism DNA Mismatch Repair Binds all mismatches except C-C Binds to MutL-MutS and methylated GATC

DNA metabolism DNA Mismatch Repair

DNA metabolism DNA Base-excision Repair DNA glycosylases recognize deaminations and remove them leaving an apurinic/apyrimidinic site (AP site)

DNA metabolism DNA Nucleotide-excision Repair Used to repair DNA lesions that cause large distortions in DNA helix (pyr dimers)

DNA metabolism Photolyase

DNA damage - mutation

DNA damage - mutation

DNA metabolism DNA SOS Repair Responds to extensive DNA damage, coordinated induction of a variety of genes

DNA metabolism DNA Repair Defects in genes encoding proteins involved in mismatch repair, nucleotide-excision repair, and recombinational repair can cause cancer Nucleotide-excision repair sole repair pathway for pyrimidine dimers genetic defect causes XP, xeroderma pigmentosa, these individuals are extremely sensitive to sunlight and quickly develop sunlight-induced skin cancer Mismatch repair Hereditary nonpolyposis colon cancer (HNPCC) linked to defects in these genes Defects in human MutL homolog, human MutS homolog Recombinational repair Recombination - linear sequence of DNA altered by cleavage and rejoining of chromosome (involves RecA protein) Repair of this type sometimes needed to reconstruct replication fork Human breast cancer genes (BRCA1 and BRCA2) produce proteins that interact with the human homolog of RecA, therefore these are linked to recombination repair 10% of breast cancers have defects in BRCA1 or BRCA2 Women with defects in these genes have a >80% chance of developing breast cancer