When transcription factors attach to the DNA strand - How do they know in which direction they have to initialize the transcription by rna polymerase? Is it always read in the same direction anyway? What about those 'promoters'? Do they influence the transcription direction?

  • $\begingroup$ Do you mean by direction which of the two DNA strands is transcribed? Or do you mean whether the polymerase goes from 5' to 3', or from 3' to 5' on a single strand? $\endgroup$ Apr 22 '14 at 16:12
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    $\begingroup$ @MadScientist Although the first question is also interesting, the second one is the one which I am interested in at the moment. $\endgroup$ Apr 22 '14 at 18:45

Transcription always proceeds in the direction 5' (5-prime) to 3' (3-prime) on the coding strand of DNA. Binding of both transcription factors and RNA polymerase to DNA depends on sequence motifs in the DNA. Transcription always happens in the same direction with respect to the chemical structure of the coding DNA strand, while the transcription direction with respect to the structure of the chromosome depends on which strand the coding sequence is found on (and thus which strand is defined as the coding strand for that gene).

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    $\begingroup$ Just to clarify, RNAP moves relative to the template strand from 3' to 5'. The transcript is polymerized from 5' to 3' and has the same sequence as the coding strand (except U instead of T). $\endgroup$
    – canadianer
    Apr 22 '14 at 18:52
  • $\begingroup$ Thanks, good point. The whole process is described, with figures, in an NCBI online book here: ncbi.nlm.nih.gov/books/NBK22085 $\endgroup$
    – jarlemag
    Apr 22 '14 at 19:10
  • $\begingroup$ Glad to hear that. You can also communicate that an answer is useful by clicking the checkmark next to the answer, "accepting" it. $\endgroup$
    – jarlemag
    Apr 23 '14 at 0:11
  • $\begingroup$ I don't think transcription always goes $5' \rightarrow 3'$ wrt to coding strand. See en.wikipedia.org/wiki/… $\endgroup$
    – Superbest
    Jun 20 '14 at 11:49
  • $\begingroup$ In that instance there are two coding strands, so the transcription still goes the same way with respect to each coding strand. $\endgroup$
    – jarlemag
    Jun 20 '14 at 14:01

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