# Do I need mRNA destabilization signals for my gene expression? If so where should I add it? # It says; "cDNA are often obtained by addition of homopolymeric tails into the 5’ non coding region which should be removed.” Which homopolymeric tails are usually used for this purpose? # Which sequences on the 3’ end that reduce mRNA stability? # It says that some genes need introns for expression hence I have to add it in my cDNA. How do introns look like and where should I add it? # Should splicing sequences be already on the plasmid or should I add it on my insert? Should I add it only when I have introns on my insert or should i always have to add it? If so where should I add it on my insert? How do the splicing sequences be like? Thanks for any inputs.