Introduction to CpG island power point presentation


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a small breifing about CpG island

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Introduction to CpG island power point presentation

  1. 1. By Muhammad Sohail 2011-ag-3378 Agri.biotechnology 5th semester
  2. 2. Outlines  CpG island  CpG sites  Relation between CpG island and gene  Where they occur  Methylation
  3. 3. CpG Islands CpG islands (CGI) are genomic regions that contain a high concentration of CpG sites.
  4. 4. CpG sites  CpG sites are regions of DNA where a cytosine nucleotide occurs next to a guanine nucleotide in the linear sequence of bases along its length.  "CpG" is shorthand for "—C—phosphate—G—", that is, cytosine and guanine separated by only one phosphate; phosphate links any two nucleosides together in DNA
  5. 5. CpG sites The "CpG" notation is used to distinguish this linear sequence from the CG basepairing of cytosine and guanine. The CpG notation can also be interpreted as the cytosine being 5 prime to the guanine base.
  6. 6. CpG islands & Genes  CpG islands located in the promoter regions of genes can play important roles in gene silencing  Housekeeping genes  Almost all housekeeping genes are associated with at least one CpG island  Tissue specific genes  About 40 % tissue specific genes are associated with islands
  7. 7. Where they occurs?  In mammalian genomes, CpG islands are typically 300-3,000 base pairs in length, and have been found in or near approximately 40% of promoters of mammalian genes. About 70% of human promoters have a high CpG content.  Based on an extensive search on the complete sequences of human chromosomes 21 and 22, DNA regions greater than 500 bp were found more likely to be the "true" CpG islands associated with the 5' regions of genes.
  8. 8. Where they occurs?  CpG islands typically occur at or near the transcription start site of genes, particularly housekeeping genes, in vertebrates.  Normally a C (cytosine) base followed immediately by a G (guanine) base (a CpG) is rare in vertebrate DNA because the cytosines in such an arrangement tend to be methylated. This methylation helps distinguish the newly synthesized DNA strand from the parent strand, which aids in the final stages of DNA proofreading after duplication
  9. 9. Epigenetic Epigenetic is the study of heritable changes in gene activity which are not caused by changes in the DNA sequence. e.g. DNA methylation
  10. 10. DNA methylation DNA Methylation is a biochemical process involving the addition of a methyl group to the cytosine or adenine DNA nucleotides. DNA Methylation stably alters the expression of genes in cells.
  11. 11. DNA methylation A DNA molecule that is methylated at the two center cytosine. DNA Methylation plays an important role for epigenetic gene regulation in development and disease.
  12. 12. Methylation & Silencing Mechanism One way cells differentiate is Methylation Addition of CH3 in Cnucleotides Silences genes in region Methylation is inherited during cell division…….
  13. 13. Epigenetic Mechanism
  14. 14. Disease Categories Associated with Methylation Loss  Aging  Cardiovascular  MI  Hypertension  Stroke  Hypercholesterolemia  Metabolic  Lipid Fatty acid  cholesterol  Diabetes (type 1 and 2)  Adiposity  • Neurologic  Chemical dependency  Bipolar disorder  Cognitive function  Asperger syndrome  Schizophrenia  Major depressive disorder  Alzheimer’s disease  Immune  Arthritis  Asthma  Antiphospholipid syndrome  Grave’s disease  Hashimoto thyroiditis  Lupus erythematosus  Multiple sclerosis