Pol II's so smart, now let me see
It make a transcript, one, two, three,
From a billion base pairs can it find
The one promoter it must bind?
I need some help, I hear it plead,
This DNA I cannot read
I cannot see where I must start
'Til TFIIs have done their part.
When TATA's bound by TBP
That sends a signal out, you see
Once DNA has made a bend
More TFIIs will soon attend.
When B arrives, it clears a place
For RNA polymerase
And F and E soon join the fun
TFIIH's the final one.
The last one is a special case
It moonlights as a helicase
And sends Pol II upon its way
To make a brand new RNA.
How does it do that, you may ask
A phosphate does the crucial task
Added on to CTD,
That's how the H sets Pol II free.
And Pol II goes its merry way
There soon will be some RNA
Then introns must be all excised
As RNA is capped and spliced.
Then PolyA polymerase
Will add a couple hundred As
For my own transcript, I can say
That all I want is one more A.