text: Coupling of RNA polymerase II (pol II) transcription can influence processing reactions in three ways.
  # localization
  #* positions mRNA processing factors at the elongation complex, which raises their local concentration in the vicinity of the nascent transcript 
  # kinetic coupling
  #* the rate of transcript can have profound effects on RNA folding and the assembly of RNA-protein complexes
  # allosteric
  #* contact between the pol II elongation complex and mRNA processing factors can allosterically inhibit or activate mRNA processing factors