BIO_325_Oct_21_08 lect 12

Thomsen review of meso patterning signals

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Unformatted text preview: Gastrulation • Neural induction Key Maternal mRNAs • Vg1 • VegT m R N A fo r W n t1 1 g r o w th fa c to r is lo c a liz e d to th e X e n o p u s e g g v e g e ta l p o le y o u n g o o c y te s o l d o o c y te K & Me to Dev ote nt 1 93 Wunt1l1n prelopmein9gets expressed at a high level in the dorsal vegetal cells of blastula Cortical Rotation moves outer cortex relative to inner cytoplasm by about 30 degrees This movement displaces pigment granules in animal pole toward the ventral side & causes cytoplasmic mixing Various evidence shows cortical rotation moves dorsal determinants move from the vegetal pole to the future dorsal side of fertilized egg The wnt signaling pathway Inactive Active Fig 2.39 BMP4 & Wnt8 gradient Fig 3.60 cell cycle: S - M M B T @ Stage 8 • Z y g o t ic g e n e a c t iv a t io n • S o m a t ic c e ll c y c le s t a r t s : G1 - S - G2 - M The Mid-Blastula Transition (MBT) S IG N A L 1 is p r o d u c e d b y : - m a t e r n a l V e g T a c t iv a t e s n o d a l a n d D e r r ie r e g e n e s - N o d a l, D e r r ie r e a n d V g 1 p r o t e in s a r e s e c r e t e d a n d in d u c e m e s o d e r m a c r o s s t h e m a r g in a l z o n e Signal 1 is Vg1 + nodals + Derriere Xnrs, Der VegT NC Vg1 Signal 2 is Vg1 + nodals + WNT11 Signal 2 of the multi-signal model Located in vegetal cells, Signal 2 is made of: • • • • • • Vg1 high levels Nodal1 high levels Nodal2 high levels Nodal4 high levels Nodal5 high levels Wnt11 (made from m a te r n a l m R N A ) NC Cells that send signal 2 are named “The Nieuwkoop Center” m id to la te b la s tu la...
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This note was uploaded on 11/11/2012 for the course ESL 100 taught by Professor He during the Spring '12 term at SUNY Stony Brook.

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