Are there size limitations for cloning into IRES vectors?
Are there size limitations for cloning into IRES vectors?
Typically, expression of the gene downstream of the IRES is optimal only if the gene cloned upstream of the IRES is 0.5–1.5 kb in size. Therefore:
You can expect reduced expression of the downstream gene when a gene larger than 2 kb is cloned upstream of the IRES.
It is better to clone a stuffer into the vector than to use the empty vector as a control.