The one of the two strand
s of DNA
that is read by RNA
. The double helix
is locally unwound, and the growing chain of mRNA
takes the place of the unwound strand. It uses RNA polymerase
to add to itself at its 3'
end as it goes along the gene
. It begins doing this at the promoter
site and stops at the terminator
The template strand is considered to be antisense, because the mRNA it makes is complementary to it but identical in sense to the other DNA strand.
Which strand of the DNA is taken as the template depends on which direction the promoter site points. It differs from gene to gene. There are even cases of genes encoded on opposite strands at the same point.