Fig. 2.

Suppression of basal transcription following heat shock is mediated by lncRNA. a Under normal conditions, RNA polymerase II (Poll II) associates with gene promoters through the help of accessory factors such as TATA-binding protein (TBP) to drive basal transcription of house-keeping genes. Phosphorylation (P) of heptapeptide repeats at serine-5 within the carboxyl terminal domain (CTD) of Pol II is facilitated by TFIIH to signify transcription initiation. b LncRNAs B5 in mice (∼178 nts) or Alu in humans (∼300 nts) are upregulated in response to heat stress. Both RNA species function in trans as repressors of basal transcription by binding to the active site of Pol II, preventing proper association with DNA, and suppressing CTD phosphorylation. TFIIH does not appear to disassociate from the complex, rather its kinase activity is suppressed following lncRNA interaction with Pol II