During transcription, the DNA strand to be transcribed will be used by RNA polymerase to synthesize a complementary strand. This strand, just like in replication, will be synthesized in the 5' to 3' direction. Thus, it will start in the 3' end of the DNA. However, the DNA, being double-stranded in nature, has two 3' ends.
If the following DNA is read in transcription, which of the following will be the start of the mRNA strand (all answers are 5' to 3')?
Template: 3' - AATTGGTTTGGTTCCTGTA - 5'
Coding: 5' - TTAACCAAACCAAGGACAT - 3'