Transcription of the start codon.

[Rhino1000]

Does the DNA sequence "ATG" get transcribed as AUG in RNA? Or does ATG get transcribed as UAC? Or does it get transcribed as CAU (reverse/antiparallel, complimentary)?

TPR biology says that GTG in DNA is transcribed as CAC in RNA. This would infer that the DNA sequence required to create the RNA start sequence "AUG" would be TAC (unless the symmetry of GTG is hiding an antiparallel relationship between the two); however, upon searching online and finding a site that may or may not be reliable, the DNA sequence ATG is the sequence for the start codon (the same nucleotide sequence as in RNA, except the U replaced with the DNA version, T).

I would think that because transcription occurs in an antiparallel manner, a DNA sequence ATG would be transcribed as CAU, so then the start codon in DNA should be CAT (which would then be transcribed to AUG).

Someone please explicate what DNA sequence is required in order to obtain the RNA equivalent of the start codon (AUG).

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[syoung]

You need to understand the different strands (sense and antisense) wiki it. Here is a double stranded DNA

5' ATG 3'
3' TAC 5'

Now from the 3' to 5' we make the mRNA

5' AUG 3'

 

[DrknoSDN]

Just remember to pay attention to if it is giving you the DNA sequence of the coding or the template strand.

If it says ATG is on the Coding strand. You know that is coding for the identical sequence on the mRNA, you just have to swap all the T's for U's.
This is the same thing that syoung explained but transcription uses the template strand as a (get ready for it...) "template" to make the mRNA so you would expect the polymerase to read 3' TAC 5' from the template in order to make AUG 5>3

 

[Rhino1000]

You need to understand the different strands (sense and antisense) wiki it. Here is a double stranded DNA

5' ATG 3'
3' TAC 5'

Now from the 3' to 5' we make the mRNA

5' AUG 3'

This clears it up very well, thank you.