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Normalization of expression data against "housekeeping" genes

  Sample User Question
Step By Step Guide

Sample User Question back to top

In "classical" expression experiments such as Northern Blots and 2D Protein Gels it is common to "normalize" data between samples using the abundances of Beta Actin (cytoplasmic actin-ACTB) RNA or protein. The rational is that Beta Actin is a common "housekeeping" gene and therefore should be expressed at roughly equivalent levels in all tissues. Using both UniGene's ( Expression Profile and the Human Protein Atlas (, determine if this is a valid approach to normalization of RNA and protein expression data accross various tissues.

Step By Step Guide back to top

  1. Open UniGene and the Human Protein Atlas.

  2. Search for "ACTB".

  3. Note the high variability of the various isoforms of ACTB at both the RNA level as seen in the UniGene Expression Profile and the Human Protein Atlas Tissue Profiles-there is too much variation in beta actin to reliably use it as a "normalization" gene.

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Revised 07/24/2007