Hi Slim,

I've worked with Activin-based luciferase reporters before and can say from experience that not all reporter constructs are as effective as each other. For me, I find that the more synthetic CAGA-SBE reporters generally work the best and can be activated by either p-Smad2/3, whilst the more endogenous based reporters such as the Ptx-Luc and ASE-Luc are more variable.

I think this variability is largely due to the differing binding thresholds between the binding elements. For example, endogenous elements are more likely to require more p-Smad2/3 bound or may even require only a certain type of pSmad2/3-Smad4 complex before being activated. Another important point is that both Smad2/3 are not necessarily expressed equally nor are activated equally, which largely depends on both the cell type and the specific combination of receptors that are expressed.

One other point to note is that Smad2 itself has no inherent DNA binding, activity, therefore Smad2-mediated activation of luciferase using these constructs is likely to be mediated through either Smad3, Smad4 or other cofactors. Again, expression and localisation of these cofactors will also influence the degree of construct activation. 

Hope this info helps.

Jason

I think you might get answers for these questions by tracking original plasmid generation (luciferase) from papers of Dr. Joan Massague, Dr. Koyi Miyazano, and Dr. Bert Vogelstein.

Hello

find links here , i hope help you

Good Luck

http://www.biomedcentral.com/content/pdf/1471-2121-7-15.pdf

http://mcb.asm.org/content/31/7/1459.full

http://hmg.oxfordjournals.org/content/18/5/861.full.pdf

http://jnumedmtg.snmjournals.org/cgi/content/meeting_abstract/53/1_MeetingAbstracts/1148