text: Actin, the regulator, holdin' it down,
  Pol II-dependent transcription, the talk of the town.
  P-TEFb, known as the positive elongation factor,
  Cdk9 and cyclin T1, the dynamic duo, a major actor.
  
  The connection between actin and P-TEFb, unclear,
  But in this study, we bring the truth near.
  Actin interacts with Cdk9, it's a fact,
  In elongation complexes, they make an impact.
  
  Immunofluorescence and immunoprecipitation assays,
  Revealed Cdk9 bindin' G-actin in amazing ways.
  Through a conserved Thr-186 in the T-loop,
  They unite, no need for a scoop.
  
  Overexpression and kinase assays in the lab,
  G-actin boosts P-TEFb's phosphorylation grab.
  Pol II's C-terminal domain gets the kick it needs,
  G-actin steps up, fulfilling its deeds.
  
  In vitro transcription experiment shows the way,
  G-actin and Cdk9 enhance Pol II's sway.
  ChIP and immobilized template assays,
  Actin recruits Cdk9, no delays.
  
  On the IL-6-inducible p21 gene expression scene,
  Actin recruits Cdk9 to where it's been.
  Histone H3 gets acetylated, a mark of fame,
  With actin and Cdk9, they play the histone game.
  
  Actin and Cdk9 increase chromatin's shift,
  Promoting transcription elongation, a powerful gift.
  Together they groove, they collaborate,
  Actin and Cdk9, an unstoppable duo, no debate.