Does step I expect a detailed understanding of HOX genes?

[PokerDoc]

I specifically refer you to the table on page 135 in the HY Cell & molecular biology

stuff like

HOXA-2 is associated with duplication of malleus and incus or HoxA-9 --> AML


I have never seen any of this anywhere else and I know this book goes into excessive detail, but I just thought i'd check and see if anyones come across this stuff somewhere else before I tossed it aside.. especially the non-clustered homeotic genes (like Emx-2) which I've never even heard of before.



Thanks

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[username456789]

God I hope not. I don't think I ever even really understood hox genes the first time around.

 

[hartbot]

I think it's unnecessary details like that which made the HY '99 edition the most useful one

 

[username456789]

I think it's unnecessary details like that which made the HY '99 edition the most useful one

Although even the 1999 version has this stuff mentioned on p.88.

But I agree, this stuff can't be particularly useful.

 

[MilkmanAl]

They're conserved across species and regulate development. Done!

 

[badasshairday]

I echo the sentiment that I never even really understood it the first time. I just know they have something to do with the proper order of development of body structures at the right places. Something like mRNA gradients or some nucleic acid gradients...... Whatever.

I finally came across the UWORLD lac operon question! I was so excited because I took two serious microbiology classes in undergrad, so I was like, "I BETTER KNOW THIS!" And I got it right. lol.

 

[PokerDoc]

I echo the sentiment that I never even really understood it the first time. I just know they have something to do with the proper order of development of body structures at the right places. Something like mRNA gradients or some nucleic acid gradients...... Whatever.

I finally came across the UWORLD lac operon question! I was so excited because I took two serious microbiology classes in undergrad, so I was like, "I BETTER KNOW THIS!" And I got it right. lol.

HAHA i got a lac operon question in Rx last night.. and it was right after i skipped over the operon section in HY MCB too hha.. I was like, if I get this wrong... i deserve it.



but luckily i got it right

 

[knuckles]

Whats the diff between hox and pax genes? thanks guys

 

[NRAI2001]

From doing a few nbme IMO the step 1 really does not ask very detailed questions at all... Atleast not the level of detail we re used to being asked from our classes. I ve read goljan about 3x , brs biochem, hy neuro...etc and for about 90% of questions I found that even FA was more detail than we really needed to know (of course knowing more helps)

 

[Vergie]

While I can't remember exactly what the question asked, I did have a HOX gene question on USMLE, so definitely know what you can about it. I also had a Sonic hedgehog gene question too.

 

[knuckles]

I bumped it so you guys could answer my question, not the original one

haha whoops

 

[doc29]

what i have in my notes...
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)

 

[knuckles]

ok so in conclusion,

Hox is segmental and ant-post orientation of the nervous system and spinal cord, cns, etc

Pax is tissue specific orientation

SHH - at zone of prolif activity for anterior/posterior patterning of limb buds

wnt-7 - at apical ectodermal ridge for dorsal/ventral limb bud patterning

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


that seem right?

 

[doc29]

...and homeobox-->segmental organization

 

[knuckles]

homeobox = hox.......right? wtf

I was under impression homeobox was just the fancy name for the conserved DNA region across aeons that coded for the hox genes....

So much for my undergraduate evolutionary developmental bio class

 

[doc29]

lol yesss my bad

 

[hoqhuuep]

These few points summarize what we had to know about Hox genes in embryo class, I don't think they could go more in depth than this...

- 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

 

[DivCurlZero]

Well, even if they do ask you about that on your test, it will likely be confined to one question at most.

 

[knuckles]

apparently BMP is also involved in dev...

all I know about it is that BMPR2 is involved in primary pulm hypertension. Is there anything else we should be aware of? thanks

 

[TheAberrantGene]

This video helped me a lot.. I think it is worth watching..

 

[worldbeater]

Quick hits:
Homeobox and TATA are used in transcription (World Q x 2)

Does anybody have the ID number on World for the sonic hedgehog gene? I thought it would be a cool fact to throw out to look cool..lol

 

[zeevee]

Quick hits:
Homeobox and TATA are used in transcription (World Q x 2)

Does anybody have the ID number on World for the sonic hedgehog gene? I thought it would be a cool fact to throw out to look cool..lol

Homeobox gene :UW ID 2015

It says that homeobox gene is a 180 nucleotide sequence that codes for transcription factors that can bind to DNA and are important in segmental organization in head to tail configuration.Mutations can result is limbs and appendages in wrong locations .
Homeobox/hox and homeodomain are the same thing .Can lead to abortion.


Sonic hedgehog gene UW 252
Involved in separation of forebrain ; failure will lead to holoprosencephaly with hypotelorism , cyclopia and proboscis

 

[Focused1]

Morphogenesis is the operative term here.. HOX => Helps Morphogenesis.