How to "normalize"
an638125 at anon.penet.fi
Fri Aug 2 16:12:01 EST 1996
> About a year ago I was under the impression that one could use the actin gene
> as a standard for Northerns. However, it appears that actin is not expressed in
> all tissues at all times at the same levels, so that there may be variations
> across your lanes using this standard, which makes it hard to normalize.
> Fortunately, I was recently informed that one could use a probe for the
> ribosomal RNA to better provide accurate standards. None of this may answer
> your question. I had thought that the only use for these "standards" was to
> provide a control for the loading amounts in the lanes.
> Hope this helps
You are right in all accounts. But the standard can be used for more than loading. For
instance, if you want to check the effect of a particular stimuli on transcription of gene
X. You can measure the levels of X and compare the ratios of X to your standard
gene. One MUST be sure that the treatment does not affect the expression of the
There are many genes that can be used as a standard which one you pick depends on
what effect the treatment will have on it: beta actin, gamma actin, cyclophilin, G6PD,
MLC-2, 28s or 18s ribosomal are some of the choices.
More information about the Methods