🦠microbiology review

Southwestern blot

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

Southwestern blot is a laboratory technique used to detect DNA-binding proteins by combining features of both Southern and Western blotting methods. It involves electrophoretic separation of proteins, followed by their transfer onto a membrane and probing with labeled DNA fragments.

5 Must Know Facts For Your Next Test

  1. Southwestern blotting detects DNA-binding proteins rather than nucleic acids or antibodies.
  2. The technique combines aspects of Southern blot (DNA detection) and Western blot (protein detection).
  3. Proteins are first separated using SDS-PAGE and then transferred to a nitrocellulose or PVDF membrane.
  4. A labeled DNA probe is used to identify specific DNA-binding proteins on the membrane.
  5. This method is particularly useful for studying transcription factors and other regulatory proteins.

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