According to the textbook, the DNA-dependent RNA polymerase catalyses polymerisation in the 5' → 3' direction, reading the template strand which has 3' → 5' polarity . The transcription follows the rule of complementarity, where Adenine pairs with Uracil (in RNA) instead of Thymine, and Cytosine pairs with Guanine .

Template: 3' TAC ATG GCA AAT ATC CAT TCA 5' Product: 5' AUG UAC CGU UUA UAG GUA AGU 3'