th-system: interaction strength expression level dependent?

[Frederik Börnke]

Dear all,

my protein of interest interacts with a target protein in an
isoform-specific manor, as determined by quantitative b-gal assays.
Binding of one of the isoforms is rather strong, another binds not
at all and some more are intermediate. When I tried to publish that
the reviewer wanted me to assure equal level of expression of all
isoforms by western-blotting. I agree that I should check expression
of the isoform which does not interact at all, but anyway, is 
interaction strength of two-hybrid proteins linked to expression
level of one of the proteins? In particular, I am using truncated
versions of the adh promoter, making western detection of hybrid
proteins a bit difficult since expression is supposed to be below
the detection level.
Any input appreciated.

Ricky 

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Frederik Boernke
Research Group of  Molecular Plant Physiology
Institute for Plant Genetics and Crop Plant Research (IPK)
Corrensstr. 3
06466 Gatersleben
Tel.  039482 -5 321
Fax. 039482 -5 515
http://www.ipk-gatersleben.de