No GFP fluorescence with TU#58, TU#60 and TU#65

[delabess]

I work with GFP cDNA from one year and I have any fluorescence detected 
when the construct with these threee cDNA (TU#58, TU#60 and TU#65) are 
electroporated in human hematopoietic cell lines. The problems of 
circularization of the chromophore or the non consensus ATG sequences 
have been suggested.
Somebody have some experienced with these constructs?
Thanks.