Positive Transcription Elongation Factor B

**Semantic type:** Amino Acid, Peptide, or Protein

**Definition:** A cyclin-dependent kinase complex that promotes the release of RNA polymerase II (Pol II) from promoter proximal pausing and leads to transcript elongation and mRNA synthesis. This complex is a heterodimer comprised of the serine-threonine kinase cyclin-dependent kinase 9 and either cyclin-T1, cyclin-T2 or cyclin-K.

**Synonyms:** - P-TEFb