Ptc contains 12 TM α helices and structurally similar

to the Niemann-Pick C1 protein, a cholesterol transporting member of the ABC superfamily

TLS Online TPP Program

#Id: 188

#Unit 5. Developmental Biology

At high concentrations (about 300 molecules/cell), activin induced expression of the goosecoid gene and instructed the cell to become the frog’s dorsal-most structures.

TLS Online TPP Program

#Id: 189

#Unit 5. Developmental Biology

Potency, commitment, specification, induction, competence, determination and differentiation; morphogenetic gradients; cell fate and cell lineages; stem cells; genomic equivalence and the cytoplasmic determinants; imprinting; mutants and transgenics in analysis of development

TLS Online TPP Program

#Id: 190

#Unit 5. Developmental Biology

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TLS Online TPP Program

#Id: 191

#Unit 5. Developmental Biology

At slightly lower concentrations (intermediate concentrations), activin (about 100 molecules per cell) activated the Xbra gene and instructed the cell to become muscle.

TLS Online TPP Program

#Id: 192

#Unit 5. Developmental Biology

At lower concentrations of activin, genes were not activated, and the “default” gene expression instructed the cells to become blood vessels and heart.

TLS Online TPP Program

#Id: 930

#Unit 5. Developmental Biology

Stem cells are sometimes referred to as “undifferentiated” due to this maintenance of proliferative properties.