Don't Forget to sign in to myEarthLink. Only after signing in can you... Move, delete & minimize features for a personalized page layout. Follow your favorite Sports teams with ESPN.
During transcription, a DNA sequence is read by an RNA polymerase, which produces a complementary, antiparallel RNA strand called a primary transcript. Transcription proceeds in the following general steps: 1  One or more sigma factor protein binds to the RNA polymerase holoenzyme, allowing it to bind to promoter DNA.he antisense strand of DNA is read by RNA polymerase from the 3' end to the 5' end during transcription (3' â 5'). The complementary RNA is created in the opposite direction, in the 5' â 3' direction, matching the sequence of the sense strand with the exception of switching uracil for thymine.
Together, the transcription factors and RNA polymerase form a complex called the transcription initiation complex. This complex initiates transcription, and the RNA polymerase begins mRNA synthesis by matching complementary bases to the original DNA strand.