Question

Which blotting technique is used for detection of proteins?

• A. Southern blotting
• B. Northern blotting
• C. Western blotting
• D. Eastern blotting

Hint:

• Mnemonic for major blotting techniques (SNoW DRoP):
  • S}outhern blot \(\rightarrow\) D}NA
  • N}orthern blot \(\rightarrow\) R}NA
  • W}estern blot \(\rightarrow\) P}rotein
• (Eastern blotting is for post-translational modifications or lipids - less common).

Answer 1

The Correct Option is C

Blotting techniques are used in molecular biology to transfer macromolecules (DNA, RNA, or proteins) from a gel (after electrophoresis) to a solid membrane support, where they can then be detected using specific probes.

• Southern Blotting (Option a): Used for the detection of specific DNA sequences. DNA fragments separated by gel electrophoresis are transferred to a membrane and then probed with a labeled DNA or RNA sequence complementary to the target DNA. (Named after Edwin Southern).
• Northern Blotting (Option b): Used for the detection of specific RNA sequences (e.g., to analyze gene expression by detecting mRNA). RNA molecules separated by gel electrophoresis are transferred to a membrane and probed with a labeled DNA or RNA sequence.
• Western Blotting (Option c): Used for the detection of specific proteins. Proteins are separated by gel electrophoresis (usually SDS-PAGE), transferred to a membrane (e.g., nitrocellulose or PVDF), and then probed, typically using specific antibodies that bind to the target protein. The bound antibody is then detected (e.g., using a secondary antibody conjugated to an enzyme that produces a colored or chemiluminescent signal).
• Eastern Blotting (Option d): A less common term, often used to refer to techniques for analyzing post-translational modifications of proteins (e.g., glycosylation, phosphorylation) or lipid analysis after blotting. It's not as standardized as the other three.

Therefore, Western blotting is the technique used for the detection of proteins. \[ \boxed{\text{Western blotting}} \]