Molecular Genetics Patterns

Question 1

Name the 5 Major Developmental Signaling Pathways

Answer 1

1. TGF-b (Transforming Growth Factor)
2. FGF (Fibroblast Growth Factor)
3. SHH (Sonic Hedgehog)
4. Wnt
5. RA (Retinoic Acid)

Question 2

What type of signalling pathway does TGF-b normally use? Notable examples include; Nodal and BMP, which antagonizes Nodal.

Answer 2

Typically use Threonine-Serine Kinase Dimers (Thr-Ser)

Question 3

Smads promote _____ Signaling

Answer 3

TGF-Beta

Question 4

To antagonize TGF-B pathways, you can either block the receptor OR you could target the typical ligand dimers. Name three notable examples of BMP-4 (tgf-b path) Antagonists.

Answer 4

1. Chordin
2. Noggin
3. Lefty

Question 5

What type of signaling do FGFs typically use?

Answer 5

Tyrosine Kinases

Question 6

How does Syndecan activate FGF signalling?

Answer 6

Two or more GAG monomers link onto Tyrosine kinases to make activated dimers.

Question 7

The gene “Nodal” , which induces the anterior visceral endoderm (AVE), falls under what Signaling Family Peptides?

Answer 7

TGF-Beta

Question 8

For the primitive streak to occur, the widespread BMP-4 must be _____ by chordin and noggin

Answer 8

Inhibited

Question 9

Two major functions of FGF of embryo development (14days)

Answer 9

1. Induces Nodal (left/right sidedness)
2. Promotes chordin and nogging (bmp-4 inhibitors)

Question 10

Too much retinoic acid wrecks the development of the ____ part of the body

Answer 10

Posterior; diagram shows legs

Question 11

To further the Rostral-Caudal axis, Retinoic Acid engages in two “Tug of wars” with what other family class? Who wins where?

Answer 11

FGF
RA wins in Anterior
FGF wins in Posterior

Question 12

3’ hox genes form more ____ structures, whereas 5’ hox genes from more ____ structures. (Anatomical Positioning)

Answer 12

• Anterior
• Posterior

Question 13

Why does too much RA result in posterior malformation?

Answer 13

• RA inhibits FGF
• FGF promotes 5’ Hox Genes
• 5’ regulates Posterior Structures

Question 14

The ____ DNA sequences consists of 3 alpha helixes and always binds to the DNA

Answer 14

Homeobox

Question 15

5’ end of Hox genes encodes which anatomical portion?

Answer 15

The Posterior

Question 16

Orthologous Genes

Answer 16

Homologous genes between different species

Question 17

Paralogous Genes

Answer 17

Homologous Genes within a species

Question 18

Loss of function mutations (knockouts of Hox genes) often lead to which anatomical transformation?

Answer 18

Anterior Transformation

Question 19

Gain of function mutation often lead to what type of anatomical transformations

Answer 19

Posterior Transformations

Question 20

What are the Otd, and Otx1/Otx genes responsible for?

Answer 20

Forming Anterior (head/brain) structures

Question 21

What are the two transcription factors that are sufficient and necessary to completely remodel the transcriptional profile of stem cells?

Answer 21

OCT4 and NANOG