Northern vs Southern vs Western Blot - HELP!

[tima]

Hello,

I have been getting questions related to Blots wrong =[ I have been going with the mnemonic: "SNoW DRoP":
Southern-DNA
Northern-mRNA
Western-Protein

But, this apparently is not enough to answer the questions correctly. Can someone PLEASE clarify this concept for me and how i can answer questions related to this topic!

THANK YOU!

[ahassan]

Try looking at Lippincott biochem..great table that will help you remember the differences between each.

GL.

[insamar]

It all depends at what you want to detect
Looking for DNA, then you need a complementary DNA probe (South)
Looking for RNA, then you need a complementary DNA probe (North)
Looking for Protein, then u need a binding antibody (West)
Looking of DNA binding protein, then u need a DNA probe (Southwest)

[Sabio]

Just to add to this
Examples of DNA binding proteins that are commonly tested in USMLE are:
Steroid receptors, Thyroid hormones, Retinoic Acid receptors, and Transcription factors.

[DrSeddik]

I don't get looking for a DNA binding protein??!!

How would the question scenario be?

[Sabio]

Originally Posted by DrSeddik

I don't get looking for a DNA binding protein??!!

How would the question scenario be?

It would be something like this
" you did cDNA clone and made it to express a product then you used a DNA probe to label it, what product are we looking for?
a- glucagon
b- CFTR receptor
c- lysosomal enzyme
d- Zink finger
e- RAS protein

Although all the options are porteins but only Zink finger protein is a transcription factor that binds DNA and leads to increased gene expression