Question

answer please!

A gene is coded by a transcript that is 1200 nucleotides long.

What would be the effect on the protein encoded by this gene, of a single nucleotide addition at position 100, position 600 or position 1150? And what would happen if that addition was inside an intron?

Answer 1

It is assumed that the transcript is the mature mRNA fully prepared for translation.

Single Nucleotide Addition at position 100 - this region could fall in the 5'-UTR region and in that case it might not get expressed in the encoded protein. However, if this region falls in actual coding region it will cause frameshift mutation and a non-functional protein will be formed or a truncated protein or a mis folded protein.

Single Nucleotide Addition at position 600 - the effect would be most disastrous as this region falls in very mid of actual coding region. The single nucleotide addition will cause a frameshift mutation and will disrupt the whole sequence of amino acids in the protein. The protein to be encoded could be now a truncated protein or mis-folded or just non-functional. Any thing can happen in such case.

Single Nucleotide Addition at position 1150 - this would probably have no effect on the protein translated as this region will fall in 3'-UTR

Single Nucleotide Addition inside intron - this addition will have no effect at all as all introns are removed during splicing.