Blot (biology)

A blot, in molecular biology and genetics, is a method of transferring proteins, DNA or RNA, onto a carrier (for example, a nitrocellulose PVDF or nylon membrane). In many instances, this is done after a gel electrophoresis, transferring the molecules from the gel onto the blotting membrane, and other times adding the samples directly onto the membrane. After the blotting, the transferred proteins, DNA or RNA are then visualized by colorant staining (for example, silver staining of proteins), autoradiographic visualization of radioactive labelled molecules (performed before the blot), or specific labelling of some proteins or nucleic acids. The latter is done with antibodies or hybridization probes that bind only to some molecules of the blot and have an enzyme joined to them. After proper washing, this enzymatic activity (and so, the molecules we search in the blot) is visualized by incubation with proper reactive, rendering either a colored deposit on the blot or a chemiluminiscent reaction which is registered by photographic film.

Southern blot

A Southern blot is a method routinely used in molecular biology for detection of a specific DNA sequence in DNA samples. Southern blotting combines transfer of electrophoresis-separated DNA fragments to a filter membrane and subsequent fragment detection by probe hybridization.^[1]

Southwestern blot

A Southwestern blot is based on Southern blotting and is used to identify and characterize DNA-binding proteins by their ability to bind to specific oligonucleotide probes.^[2] The proteins are separated by gel electrophoresis and are subsequently transferred to nitrocellulose membranes similar to other types of blotting.

Other blots

• Northern blot for RNA
• Reverse Northern blot for RNA
• Western blot for proteins
• Far-Western blot for Protein-Protein
• Eastern blotting for posttranslational modification
• Far-Eastern blot for Lipids, Drugs and Hormones
• Dot blot
• Slot blot

See also

• Immunoscreening

References