Question

Ovalbumin is the major protein of egg white. The chicken ovalbumin gene contains eight exons separated by seven introns. Should one use ovalbumin cDNA or ovalbumin genomic DNA to express the protein in E. coli bacterial system? Explain your answer.

Answer 1

In bacteria splicing do not occurs to remove the introns from mRNA. So if you use ovalbumin DNA transcription will occur but translation of mRNA contains introns would not occur due to absence of splicing and you will not get protein. If you use ovalbumin cDNA which is made from processed mRNA that do not contains introns, there is no need to splice the mRNA produced from cDNA and translation of mRNA will occur.

So you must use cDNA rather than DNA to get the functional protein.