I have done expression experiment, but there is no protein. Why?

Answer: A correct DNA sequence with a promoter does not guarantee you to get protein expressed. Many factors contribute to the success or failure of protein expression 1) Did you use the right type of expression vector for your expression host system, for instance our pReceiver-M01 vector is for mammalian cell expression and pReceiver-B01 is for bacterial expression? 2) If the protein is a membranous protein, does it need target sequence for proper localization? 3) Will the over-expressed protein be toxic to the host? 4) Will the protein be folded into a right three-dimensional structure for its proper function and/or immunological-assays? 5) Have you checked the sequencing to see if you get an alternative splicing variant?