BIOL 303 Lecture Notes - Lecture 16: Cdx2, Pitx2, Activin And Inhibin
27 Apr 2016
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S49 lec 15 pdf: left-right axis spec in chick : in other orgs don"t know really how. S50 note epiblast (sheet of ecto), primitive streak (where gastrulation occurs). At most anterior end of primitive streak have hensen"s node which is axial meso (equival of dorsal meso in amph/z. fish) axial meso gives rise to notochord (dorsal meso?) (locate in pic). For lr axis we have asym gene expression: sonic hedgehog expression on left, Around hensen"s node / bmp and activin receptors on right, around hensen"s node. Recall crb normally inhibs bmp, however in context of lr axis, crb and bmp work together to turn on nodal gene (tfg-b family). S53 recall early exp of shh around node region, slightly later, we see exp of cereberus in lpm only on left side (turned on by shh). Leading to activation of nodal only on left (turned on by crb and bmp).
