From the original paper that describes the vector it is simply pcDNA3:
In summary, we have modified the vectors, pcDNA1 and pcDNA3, by substituting an EF-1alpha promoter for the CMV promoter. The resulting vectors, pcDEF1 and pcDEF3
Indeed Mark, the first thing I've done before posting this question was to look at the paper, but still, from the described strategy some things are not clear. If the CMV promoter was removed from pcDNA3 using SpeI and EcoRI, then the T7 promoter is gone. Or was it reintroduced during the reconstitution of the MCS? And if not, is there another priming site for forward sequencing of inserts?
Sorry Olivier, did not realise from your question that you were looking for such a specific detail and missed that point. Based on the details of pEF-BOS it would suggest that the T7 promoter is missing and no new priming site available.
BTW, the expression level of this vector is extremely high in cells with high transfection efficiency such as 293T. I use this vector for eukaryotic protein purification some times.