The enzyme responsible for mRNA transcription synthesizes mRNA from the 5' to 3' end. Therefore, the upper strand will be termed as the template strand. The transcription will take place from left to right.
Explanation:
According to molecular biology concepts, two things determine the direction of transcription:
The location of the promoter sequence (a DNA sequence that kick-starts transcription). It is also the region to which RNA polymerase binds and starts transcription.
A start codon i.e ATG in the antisense strand. Here, the upper strand (3' to 5') contains the start codon.
RNA polymerase reads from 3' to 5'. Here, since the location of the promoter is not given, the strand running from left to right (3' to 5') will be the template and the mRNA will be synthesized in the 5' to 3' (left to right direction).
