I am having some doubts regarding junction primers.If we design exon exon junction primer, let's say if my gene of interest is having some 5 exons, if the junction primer is designed at 4,5 exons junction, the sequence starting from that junction to rest will be amplified. what about the sequence behind this primer (exon 5). How to get the entire sequence of mRNA in cDNA using junction primers. And also how many junction primers should i design? please kindly clarify my doubts.