RNA blot (Northern)

The RNA blot or Northern blot (named after the DNA blot (Southern) for genomic DNA fragments) is a molecular biology technique used to separate and identify pieces of RNA. RNA molecules are separated by mass on a gel, transferred (blotted) onto a cellulose or nylon membrane, and then labelled with complementary DNA or RNA molecules. These probes are either radioactive, typically ³²P, or contain labelled nucleotides, e.g. DIG-dNTPs, recognisable by antibodies. RNA molecules can be detected and roughly quantified via probe hybridisation.

The principle of the method is nicely illustrated in this diagram and this video.

Designing RNA probes

• DNA probes, esp. using DIG-antibody detection, often give no/weak signal; RNA probes often better here [1]
• minimum probe length around 25 nt (anybody has a reference for this?) [2]
• DNA probes may be usable for both qRT-PCR and RNA blots [3]

Lab-specific protocols

• Endy:Northern Blot, 32P End-Labeled Probes
• Endy:Northern blot, AlkPhos end-labeled probes

See also

• RNA
• RNA Extraction
• RNA electrophoresis
• BE.109:Systems engineering/Measuring DNA, RNA, protein

External links

• RNA blot protocol for cells in culture, complete with materials (1999) by Howell lab, UCSD
• detailed RNA blot protocol for DIG probes (2000) by Arnoud van Vliet
• archived protocol conversations from Protocol Online
• index of RNA blot protocols from Protocol Online
• RNA preparation and blotting protocol (2006) by Kelly lab, Washington Uni
• RNA blot protocol by Allen Gathman from Southeast Missouri State Uni
• The basics of RNA blots, Ambion general article
• Techniques to detect mRNA - includes RNA blot, Ambion TechNotes
• Pack insert DIG RNA detection kit, Roche
• Probe hybridization protocol - Parker lab (don't know how many stars to give it!)