When the peroxidase system is blocked or when it is hereditarily absent from the cells, the rate of formation of thyroid hormones falls to zero

TLS Online TPP Program

#Id: 168

#Unit 5. Developmental Biology

Expression of Pax6 protein constitute the competence of the surface ectoderm to respond to the optic vesicle.

TLS Online TPP Program

#Id: 169

#Unit 5. Developmental Biology

The optic vesicle secrete two paracrine factors:

 BMP4

 FGF8

TLS Online TPP Program

#Id: 170

#Unit 5. Developmental Biology

BMP4 

A protein that is received by the lens cells and induces the production of the Sox transcription factors.

TLS Online TPP Program

#Id: 171

#Unit 5. Developmental Biology

FGF8 

A secreted signal that is received by the lens cells and induces the production of the L-Maf transcription factor.

TLS Online TPP Program

#Id: 172

#Unit 5. Developmental Biology

Combination of Pax6, Sox2, and L-Maf in the ectoderm is needed for the production of the lens and the activation of lens-specific genes i.e. δ-crystallin.

TLS Online TPP Program

#Id: 173

#Unit 5. Developmental Biology

If Pax6 is lost (fruit flies, frogs, rats, humans) complete loss or reduction of the eyes