Keuhn

Question 1

morphogens

Answer 1

Diffusible molecules that are released locally; react with cells to govern pattern of development

ex: Bone Morphogenic Proteins (BMPs): one of the pivotal developmental signaling molecules. Important in things derived from mesoderm.
•Deal with muscular, neural and CT differentiation but also help regulate cell division, apoptosis, and cell migration.

Hedgehog series: (e.g. SHH) critical developmental gene requires cholesterol to become active. Comes from the notochord.•
Three forms: desert (spermatogenesis), indian (gut, cartilage, postanatal bone growth) and sonic (spine, vertebrae, somites, regional differentiation; note, associated w/ ventral).

WNT: Critical in pattern development and axis patterning among other things, it uses β-catenin to activate gene sequences. Critical for early development.•
(Mouse “Int1” =Drosophila Wg “Wingless”  Human Wnt); 15 types(associated with most things dorsal, particularly muscle, limb patterning)

Question 2

Transcription factors

Answer 2

Binds to DNA.  Many are Homeobox or HLH families.
A large class of intracellular proteins that regulate expression of target genes; either activate or repress. Includes:Histones, the proteins that bind & organize DNA

Hox/Homeobox proteins found in all animal species, including invertebrates that regulate segmental separation and development.
Paired Box (Pax) genes, with paired domains; factors which can either activate or repress specific genes