The following eukaryotic template strand contains a CDS regi

The following eukaryotic template strand contains a CDS region of a gene. First, draw the corresponding mRNA molecule and be sure to label the orientation. Second, translate the CDS into a polypeptide. Assume that there are no introns.

                                    3’-ATGGTTTTACGGGCTTCCAATCGTACC-5’

Solution

3’-ATGGTTTTACGGGCTTCCAATCGTACC-5’

RNA polymerase reads 3\'--5\' DNA strand to make mRNA. In mRNA, Uracil is written in place of Thymine. So, reading the given sequence in 3\' to 5\' direction, the mRNA will be:

5\'-UACCAAAAUGCCCGAAGGUUAGCAUGG-3\'

Translating the CDS region means there will be a start codon near the 5\' end of mRNA and a stop codon near 3\' end. Translation can take place in three possible ways from 5\' to 3\' direction. So we will look for a nucleotide sequence beginning with start codon (AUG) and ending with anyone stop codon.

5\'-U-ACC-AAA-AUG-CCC-GAA-GGU-UAG-CAU- GG -3\'

Here, if we start translation from second letter, we get a start codon AUG and a stop codon UAG as well. hence the sequence between these two codons codes for a protein as follows:

5\'- Met(START) -Pro - Glu- Gly - STOP-3\'