Eastern blot on the landscape

04 May 2007

Updated 09 May 2007

Anyone with an interest in molecular biology will probably have heard of Southern blots, northern blots and western blots, used to analyse DNA, RNA and proteins, respectively. Eastern blots, on the other hand, will be found ranked alongside fairies, unicorns, and a free lunch. They don't exist. Or rather, they didn't until Yukihiro Shoyama and colleagues at Kyushu University, Japan, claimed to have developed one.

Southern blots were named after Ed Southern, at the University of Oxford, who developed them in the 1970s. The technique kicks off with an enzyme to chop DNA into smaller fragments; the fragments are passed through an agarose gel; the gel is treated with a solution that splits the double-stranded DNA fragments into single strands;the single stranded fragments are transferred onto a sheet of nitrocellulose; and the nitrocellulose is probed with complementary single-stranded DNA fragments. A similar technique was developed a few years later to analyse RNA, and so - with the hilarious wordplay too good to miss - the northern blot was born (small 'n' since it wasn't named after Northern, or any researcher).

In the 1980s, the technique was evolved further to detect proteins. This time, antibodies, rather than complementary strands, are used to probe the nitrocellulose sheet for proteins of interest. This became known as a western blot, but is sometimes called an immunoblot.

So what could an eastern blot possibly be used for? Nothing, according to the consensus of internet bloggers.

But Shoyama's team beg to differ: they investigated the small