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Molecular Embryology PART 1


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This PPT is a simplified introduction for molecular embryology. It includes molecular regulation of Heart, GIT, Liver, Pancreas, Kidney and somites Development. This will be followed by another PPT with molecualr regulation of other important organs as Brain and spinal cord. I hope that I could make it as simple as possible, waiting for your valuable comments. Enjoy my dear friends.

Published in: Health & Medicine
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Molecular Embryology PART 1

  1. 1. Molecular Embryology By: Dr. Khaled El Masry Assistant Lecturer of Human Anatomy & EmbryologyMansoura Faculty of Medicine, Mansoura University, Mansoura , Egypt. 2013
  2. 2. Molecular Regulation of Cardiac Development
  3. 3. BMP 2, 4 + Inhibitors of WNT genes (In Endoderm & Lateral PlateMesoderm ) Stimulate Production of Signals from Anterior Cranial Endoderm Expre ss NKX 2.5 Specify Cardiogenic Field in Overlying Mesoderm. Role in Cardiac Septation. Role in Conducting System Development. TBX-5 ( another Expressed later than NKX transcriptional factor) 2.5 contain T- Box. Role in Cardiac Septation
  4. 4. Molecular Regulation of SomitE Differentiation
  5. 5. Limb & body wall Epaxial muscles Activate Myogenin & MRF-5 musclesWNT proteins MYF-5 MYOD ( from Neural Tube) Myotubes & Myofibrils DM Midpart NT-3 (from Neural Tube) VM SHH Dermis D Scleroto me PAX 1 Initiate cascade of cartilage & bone forming genes Vertebral formation L BY: Interaction ( ) BMP-4 ( from lateral plate mesoderm) & WNT proteins ( fromDr. Khaled El Epidermis) WNT proteins PAX 3 Specify Dermomyotome Region of Somites Masry ( from Neural Tube)
  6. 6. Molecular Regulation of Gut Development
  7. 7. Differentiation of different regions of gut & its derivatives is dependent uponReciprocal interaction ( ) Endoderm of GUT & Surrounding SplanchnicMesoderm. SHH ( Expressed throughout gut endoderm) Induce expression HOX genes in Mesoderm Once expressed & Mesoderm specified by HOX genes Mesoderm instruct Endoderm to form various regions of Midgut & HindgutSimilar Interactions are responsible for Partitioning ofForegut.
  8. 8. Molecular Regulation of LIVER Development
  9. 9. All Foregut Endoderm has the ability to express liver-specific genes & todifferentiate into Liver tissue But This expression is blocked by factors produced from surrounding tissues including: Ectoderm, non- cardiac mesoderm & Notochord. Liver Development occurs when: Cardiac Mesoderm FGF4 Block the inhibitory signals in prospective hepatic RegionThis process is partially Cells differentiate intoregulated by HNF 3,4 hepatocytes & Biliary cell(Hepatocyte Nuclear lineageTranscription Factors 3 & 4 )
  10. 10. Molecular Regulation of Pancreas Development
  11. 11. Notochord FGF & Suppress SHH ( in Activin gut endoderm that form the will pancreas Upregulate PDX genes ( Pancreatic & Duodenal Homeobox genes) PAX 4,6 Specify expression endocrine cell lineage Cells expressing Cells expressing PAX 6 PAX 4 & 6 only α β Cells δ Cells γ Cells Cells ( glucagon)(Insulin) (Pancreatic (Somatostat polypeptide)
  12. 12. Molecular Regulation of Kidney Development
  13. 13. Differentiation of the kidney involves interaction between the epithelium of Ureteric Bud & the mesenchyme of Metanephric Cap. FGF 2 BMP Ureteric Bud 7 Metanephric Cap RE T MET GDNF ( Glial Derived Neurotrophic Factor ) HGF ( Hepatocyte Growth Factor )Thus, Signaling Pathway is established between these
  14. 14. Block Apoptosis Stimulate proliferation of Metanephric Cap FGF Maintain WT 1 2 production BMP 7 Ureteric Metanephri Bud GDN c Cap F HGFMake the metanephric Cap competent to WT respond to induction by Ureteric Bud 1Stimulate growth Regulate productionof Ureteric Bud of GDNF & HGF