Based on my previous question on ReseachGate,

I transfected the gene of Norepinephrine Transporter into human colon cells. The sequence of the vector has been confirmed correct. Usually, after transfection, the transfected cells are selected for stable expression, then divided into clones, and Western blotting is done to check the protein expression. However, I wanted to save time and confirm the transfection effect rapidly, so I decided to check the mRNA of the transfected cell.

One thing confused me: I used the cDNA of transfected cells to detect the gene by RT-PCR, and I also used the original vector and cDNA of non-transfected cells as a comparison. I did short PCR (the primer was designed by NCBI BLAST) and full-length PCR. As the figure shows, the transfected group does have a band compared to the non-transfected, but its size became larger than the original gene. The size of the PCR product was supposed to be 500bp and 2kbp as designed, but the PCR product of transfected cells tends to be 700bp and 3kbp. That's strange.

I also checked the beta-actin as the housekeeper of both transfected and non-transfected, and the result was normal.