Expression in Alcaligenes eutrophus

[Volker Seibert]

Dear netters, 
    I am trying to complement a mutated gene on the 80 kb degradative 
plasmid pJP4 (IncP) of Alcaligenes eutrophus JMP134. I cloned the intact 
gene into the broad host range vector pDSK519 (IncQ) which carries a lac-
promotor followed by a lacZ gene with an integrated multiple cloning site. 
It lacks a lacIq gene. Although this construct showed expression in E. coli, 
after transfer to A. eutrophus no activity could be measured. After 
reisolation of the plasmid from A. eutrophus and transformation into E. coli 
expression was still there. lac-promotors have been shown to work in many 
pseudomonas species. Has anyone  an idea why my cloned gene was not 
expressed?
Thanks in advance,
Ursula Schell
Univ. Stuttgart
Adress: Volker.Seibert at po.uni-stuttgart.DE