I am trying to tag moxCerulean3 to the N-terminus of a gene of interest. In other words, I'd like to place this reporter on the first exon of the gene right after the start codon. I've been using Benchling to design the homology arms (HA, ~800bp for left and for right HA), but I am having trouble doing so on Benchling because I want the fluorescent reporter gene to be on the N-terminus. So, I need the bases that are upstream of the start codon, but I'm having trouble doing so.