Do I have to include an internal poly(A) signal in the retroviral expression cassette for my gene of interest (GOI)?
Do I have to include an internal poly(A) signal in the retroviral expression cassette for my gene of interest (GOI)?
No. The GOI or selection marker expression cassette in the retroviral vector should not include a poly(A) signal or any other transcription termination signal, since it is located in the 3' LTR of the retroviral vector. A transcription termination sequence in the middle of a retroviral construct can lead to the premature cleavage of viral genomic mRNA, resulting in the loss of downstream sequences that are essential for efficient packaging and transduction of the target cells.