Step I I have no Idea what these genes do

[HelpPleaseMD]

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Sonic hedgehog gene / Wnt-7 gene. What do these things do? Im reading the first aid section on it but it isn't sinking in.

Thanks

 

[Staradmiral]

its pretty straight forward. Shh is at the Zone of Polarizing activity and mediates ant-post patterning, while Wnt 7 is at the Apical ectodermal ridge and mediates ventral dorsal patterning. It's straight out of BRS embryology

 

[Lonely Sol]

shh also mediates Holoprosencephaly seen in Trisomy 13

 

[usmleq]

its pretty straight forward. Shh is at the Zone of Polarizing activity and mediates ant-post patterning, while Wnt 7 is at the Apical ectodermal ridge and mediates ventral dorsal patterning. It's straight out of BRS embryology

its pretty straightforward, based on this post and your post in the von gierke's thread, that you are a douchebag.

 

[mtwop]

this is great

 

[Flapjacks]

its pretty straightforward, based on this post and your post in the von gierke's thread, that you are a douchebag.

lol wut?

 

[Phloston]

"Anterior" and "posterior" are usually used for proximal locations, whereas "ventral" and "dorsal" are used for distal ones (in general).

So you can remember Sonic hedgehog gene is at the base of the limbs (i.e. proximal) by the fact that it organizes patterning anterior-posterior. Similarly, you can remember that Wnt-7 is patterning along the apical ectodermal ridge (i.e. distal) by the fact that it organizes patterning ventral-dorsal.

In terms of the USMLE though, if they're going to ask us about this stuff, Lonely Sol has made a good point that Sonic Hedgehog is holoprosencephaly. I've encountered a vignette in a practice question before with holoprosencephaly and then they asked about which gene was affected.

Also, FA says for the Homeobox (Hox) gene that mutations can lead to limbs in the wrong locations. Know that Hox mutations additionally cause polydactyly, syndactyly or synpolydactyly. I've also encountered this in a practice question.

Another tid bit from QBank: BMP (bone morphogenic protein) is necessary for induction of the neural crest and bone morphogenesis.

 

[Aclamity]

lol wut?

the dude pretty much quoted FA and said "it's pretty straightforward." OP wouldn't have created this thread if FA was that straightforward. Staradmiral probably doesn't even understand what all that stuff means--probably the kind of person who blindly memorizes things without understanding them.

 

[lemonade90]

Sonic hedgehog gene / Wnt-7 gene. What do these things do? Im reading the first aid section on it but it isn't sinking in.

Thanks

Sonic the hedgehog has spikes going in the Anterior to Posterior direction when he lies on his back.. His spikes are sharp and polarizing (ZPA). Just remember hte other one does the other thing and is made in the AER.

Lame I know, but works for me.

 

[HelpPleaseMD]

Sonic the hedgehog has spikes going in the Anterior to Posterior direction when he lies on his back.. His spikes are sharp and polarizing (ZPA). Just remember hte other one does the other thing and is made in the AER.

Lame I know, but works for me.

Exactly what I needed. Thanks.

 

[HelpPleaseMD]

"Anterior" and "posterior" are usually used for proximal locations, whereas "ventral" and "dorsal" are used for distal ones (in general).

So you can remember Sonic hedgehog gene is at the base of the limbs (i.e. proximal) by the fact that it organizes patterning anterior-posterior. Similarly, you can remember that Wnt-7 is patterning along the apical ectodermal ridge (i.e. distal) by the fact that it organizes patterning ventral-dorsal.

In terms of the USMLE though, if they're going to ask us about this stuff, Lonely Sol has made a good point that Sonic Hedgehog is holoprosencephaly. I've encountered a vignette in a practice question before with holoprosencephaly and then they asked about which gene was affected.

Also, FA says for the Homeobox (Hox) gene that mutations can lead to limbs in the wrong locations. Know that Hox mutations additionally cause polydactyly, syndactyly or synpolydactyly. I've also encountered this in a practice question.

Another tid bit from QBank: BMP (bone morphogenic protein) is necessary for induction of the neural crest and bone morphogenesis.

This should be in the First Aid section instead. Wow.

 

[beeitchness]

the dude pretty much quoted FA and said "it's pretty straightforward." OP wouldn't have created this thread if FA was that straightforward. Staradmiral probably doesn't even understand what all that stuff means--probably the kind of person who blindly memorizes things without understanding them.

It actually is pretty straightforward..

 

[tjquinn]

Learn shh, had two questions on it, one was directly about shh, the other was about trisomy 13

 

[Garrus]

My stupid way of remembering Sonic Hedgehog...

Sonic the Hedgehog is currently a polarizing character, as the Sonic games being put out right now are really meh, but people have a lot of nostalgia for him. Zone of polarizing activity.

Sonic patterns Anterior-Posterior because his character can only run forwards and backwards.

Sonic deals with Holoprosencephaly because his eyes are literally linked to each other at the middle, sort of like how Holoprosencephaly has brain/eye linkage.

Wnt is just the other one...hope that helps!

 

[futuredoctor10]

Sonic the hedgehog has spikes going in the Anterior to Posterior direction when he lies on his back.. His spikes are sharp and polarizing (ZPA). Just remember hte other one does the other thing and is made in the AER.

Wow I love this... will never get these 2 mixed up again!!!!!!

 

[Morsetlis]

I knew there was a reason they hired an 80 year old guy from Italy to teach us this stuff.

Nobody else could understand it.

 

[doc10487]

bumping it up! helped cleared up some key concepts. Apparently this has become high yield.


in addition to SHH details been mentioned.
here are the rest

Hox gene--> responsible for general anterior-posterior patterning of nervous system.

1. Retinoic acid disrupts HOX gene function-->Craniofacial,CNS,CV defects

2. Hox gene fail to activate along midline of head---> Holoprosencephaly



Pax gene--> important for tissue and organ formation. There are 9 members of pax genes, but imporatant ones are

Pax 2- wilm's tumor

Pax6- Aniridia

pax 3- waardenburg syndrome(deafness,pigmentation etc)



Hox is segmental and ant-post orientation of the nervous system and spinal cord, cns, etc
Hox features:
- caudalizing factor (cranial-caudal axis)

- distalizing factor (upper and lower limbs)

- Hox knockout --> cranial-ized or proximal-ized

- Hox overexpression --> caudal-ized or distal-ized

- more Hox = more retinoic acid


Pax is tissue specific orientation

FGF - at apical ectodermal ridge for lengthening of limbs / mesoderm