Gene expression

Only one of the DNA strands is transcribed for a given gene, but for another gene, the other strand can be transcribed.

This allows each gene to define on DNA:

• The transcribed strand (or anti-sense strand): complementary sequence to RNA
• The non transcribed strand (or sense strand): sequence similar to RNA

Upstream: 5' end on the sense strand. It is the promoter end

Downstream: 3' end on the sense strand. It is the end of the gene