Transcription

Act 1 :Initiation

- The transcription factors locate the promoter (TATA) and the terminator (AAAUAAA) and begin the process of transcribing pre-mRNA.
- The strand being used to make the pre-MRNA is called the template or antisense, the other strand s called the coding or sense strand
- the initiation complex is made by RNA polymerase II

Act 2 :Elongation

- When being copied, th pre-mRNA is the same as the coding strand except that the T's are replaced with U's
- The pre-mRNA strand starts from the (TATA) sequence and stops at the termination sequence (AAAUAAA) in a 5' to 3' direction

Act 3 :Termination

- Once the Polymerase II reaches the terminator sequence the pre-mRNA cuts off and the DNA twists back together
- The pre-mRNA is guarded by a G-cap at the 5' end and a poly-A tail on the 3' end
- the useless introns are taken out of the pre-mRNA by splicosomes made up of proteins and SnRNP's.