actin as internal standard in RT-PCR

[rey garcia]

Sorry I forgot to put a title to my first posting.

Help! Urgent!

In semi-quantitative RT-PCR, is it valid to use beta-actin as an
internal standard when comparing the expression of a gene in DIFFERENT
TISSUES? Or is it only valid when comparing the expression of a gene in
a specific tissue at different developmental stages?

If the answer to question 1 is "no", what internal standard is best to
use? Please e-mail responses to the address below:

rey.garcia at stonebow.otago.ac.nz

Thanks heaps.