Question

Consider the following segment of DNA is part of a gene, 

Left  5'.... ACTGACTGACAGTC..3' 

       3'.... TGACTGACTGTCAG... 5'  RIGHT 

during RNA transcription, this double-strand molecule is separated into two single strands from the right to the left and the RNA polymerase is also moving from the right to the left of the segment. Please predict the peptide sequence(s) produced from the mRNA transcribed from this segment of DNA. (Hint: First determine the mRNA sequence, then use the genetic codon table to translate the mRNA into peptide. Please note that there could be more than one reading frames.) 

Answer 1

The DNA segment is

5’ – ACTGACTGACAGTC – 3’

3’ – TGACTGACTGTCAG – 5’

Since the RNA polymerase always move from right to left, the mRNA sequence that it will form is

5’ – ACUGACUGACAGUC - 3”

Now, moving on we know that each of the amino acid is a series of three nucleotide which is known as codon. Based on the sequence, the mRNA is determined and then it can be translated into the peptide.

5 ‘ – Thr – Asp – stop – 3”

5” – AC – Stop -3”

5” – Stop - Leu - Thr - Val -3”