Diagenode

Topoisomerase IIα promotes activation of RNA polymerase I transcription by facilitating pre-initiation complex formation.


Ray S, Panova T, Miller G, Volkov A, Porter AC, Russell J, Panov KI, Zomerdijk JC

Type II DNA topoisomerases catalyse DNA double-strand cleavage, passage and re-ligation to effect topological changes. There is considerable interest in elucidating topoisomerase II roles, particularly as these proteins are targets for anti-cancer drugs. Here we uncover a role for topoisomerase IIα in RNA polymerase I-directed ribosomal RNA gene transcription, which drives cell growth and proliferation and is upregulated in cancer cells. Our data suggest that topoisomerase IIα is a component of the initiation-competent RNA polymerase Iβ complex and interacts directly with RNA polymerase I-associated transcription factor RRN3, which targets the polymerase to promoter-bound SL1 in pre-initiation complex formation. In cells, activation of rDNA transcription is reduced by inhibition or depletion of topoisomerase II, and this is accompanied by reduced transient double-strand DNA cleavage in the rDNA-promoter region and reduced pre-initiation complex formation. We propose that topoisomerase IIα functions in RNA polymerase I transcription to produce topological changes at the rDNA promoter that facilitate efficient de novo pre-initiation complex formation.

Tags
Bioruptor
Chromatin Shearing
ChIP-qPCR
IPure kit

Share this article

Published
March, 2013

Source

       Site map   |   Contact us   |   Conditions of sales   |   Conditions of purchase   |   Privacy policy