BIOL 430 2010 lecture 9 handout 6 slides

BIOL 430 2010 lecture 9 handout 6 slides - 1 BIOL 430...

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Unformatted text preview: 1 BIOL 430 Lecture 9 January 29 th 2010 Handedness Origin and specification of the germ BIOL 430 Molecular Genetics of Development 2010 Dr. Ian Chin-Sang (www.chin-sang.ca) Origin and specification of the germ layers Mesoderm Induction Signal Transduction in Development 1. Ligand (extracellular) 2. Receptor (on membrane) 3. Effectors (A,B, C i.e. adaptors, kinases, phosphatases) 4. Regulation of of transcription 5. Changes in actin/cytoskeleton 1. 2. BIOL 430 Molecular Genetics of Development 2010 Dr. Ian Chin-Sang (www.chin-sang.ca) A B C Off On On Transcription 3. 4. 5. nucleus wild type June 2004 1997 BIOL 430 Molecular Genetics of Development 2010 Dr. Ian Chin-Sang (www.chin-sang.ca) myostatin mice [PDF] gdf-8 knock out (myostatin) Organ Handedness is under genetic control BIOL 430 Molecular Genetics of Development 2010 Dr. Ian Chin-Sang (www.chin-sang.ca) shh : secreted molecule, ectopic expression can lead to left/right heart randomization activin, lefty, nodal : all TGF- β like molecules pitx2 : transcription factor—key player in “leftness” Fig. 3.41 Can the beating of cilia set up left-right asymmetries? wt heart looping (left) iv heart looping (right) 50% BIOL 430 Molecular Genetics of Development 2010 Dr. Ian Chin-Sang (www.chin-sang.ca) iv encodes left/right dynein motor protein Kartagener’s syndrome: 50% show situs inversus and respiratory problems cilia fail to beat in respiratory lining (lacks dynein) Cells on node have cilia that beat in one direction— early asymmetry? Fig. 3.40 BIOL 430 Molecular Genetics of Development 2010 Dr. Ian Chin-Sang (www.chin-sang.ca) Fig 3.42 2 Fate Map Specification map Fig. 3.44 No neural tissues develops from explants of cells from the animal half and muscle develops only from the most dorsal mesoderm. Therefore these tissues have not been specified. Fig. 3.54 BIOL 430 Molecular Genetics of Development 2010 Dr. Ian Chin-Sang (www.chin-sang.ca) Fig. 3.50 BIOL 430 Molecular Genetics of Development 2010 Dr. Ian Chin-Sang (www.chin-sang.ca) When cultured separately animal cap cells or vegetal cells do not differentiate mesoderm. Only when cultured together mesoderm is formed (muscle and notochord)....
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This note was uploaded on 12/06/2011 for the course BIOL 430 taught by Professor Dr.ianchin-sang during the Winter '10 term at Queens University.

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BIOL 430 2010 lecture 9 handout 6 slides - 1 BIOL 430...

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