construct preparation

I want to see the functional effect of a snp located on 3'utr (in mammalian cells)
will anyone guide me to design the experiment
Actually I'm facing one problem that I've selected vector pGL4 (acc. to promega vector selecter option, keeping in mind for Protein-Protein interction studies))
but the dna fragment (which is having snp of interest) does'nt have any restriction sites compatible with pGL3/4 vector 
Now how to add linkers/adapters to rectify this problem?
please help me in this matter.