DNA template, Primers, RNA polymerase, dNTPs, Buffer solution

You are indeed correct that the DNA template, i.e. the DNA you have already isolated, is important since it contains the target sequence to be amplified. Thereafter, you also need primers, which are short sequences of nucleotides that provide the starting point for DNA synthesis, in this case they have been synthesized to bind to the transgene in the mouse model, which is not found in control mice. You are also correct that you need a polymerase enzyme to synthesize the new strands, using the dNTPs (deoxynucleotide triphosphates), which are the building blocks for the synthesis of the new strand. The buffer solution is important to maintain the optimal pH and ionic strength for the activity of the polymerase. You need to consider which polymerase enzyme you need though. Please consider this question and try again.