Topoisomerases and yeast rRNA transcription: Negative supercoiling stimulates initiation and topoisomerase activity is required for elongation

TY - JOUR

T1 - Topoisomerases and yeast rRNA transcription

T2 - Negative supercoiling stimulates initiation and topoisomerase activity is required for elongation

AU - Schultz, Michael C.

AU - Brill, Steven J.

AU - Ju, Qida

AU - Sternglanz, Rolf

AU - Reeder, Ronald H.

PY - 1992

Y1 - 1992

N2 - Previous work has shown that rRNA synthesis is strongly inhibited in yeast top1-top2 double mutants. Here, we show that inactivation of yeast topoisomerases can have paradoxical effects on transcription by RNA polymerase I. For example, transcription of ribosomal minigenes on extrachromosomal plasmids is greatly stimulated in top1-top2 cells while accumulation of full-length endogenous rRNA is strongly inhibited. We present evidence for a mechanism that can partly account for these opposing effects on transcription. On the one hand, transcription initiation can be stimulated owing to an accumulation of negative superhelicity because polymerase I prefers to initiate on negatively supercoiled templates. Conversely, synthesis of full-length rRNA is inhibited owing to the fact that chain elongation requires a DNA relaxing activity.

AB - Previous work has shown that rRNA synthesis is strongly inhibited in yeast top1-top2 double mutants. Here, we show that inactivation of yeast topoisomerases can have paradoxical effects on transcription by RNA polymerase I. For example, transcription of ribosomal minigenes on extrachromosomal plasmids is greatly stimulated in top1-top2 cells while accumulation of full-length endogenous rRNA is strongly inhibited. We present evidence for a mechanism that can partly account for these opposing effects on transcription. On the one hand, transcription initiation can be stimulated owing to an accumulation of negative superhelicity because polymerase I prefers to initiate on negatively supercoiled templates. Conversely, synthesis of full-length rRNA is inhibited owing to the fact that chain elongation requires a DNA relaxing activity.

KW - RNA polymerase I

KW - Supercoiling

KW - Topoisomerases

KW - Transcription

KW - Yeast

UR - https://www.scopus.com/pages/publications/0026725797

UR - https://www.scopus.com/pages/publications/0026725797#tab=citedBy

U2 - 10.1101/gad.6.7.1332

DO - 10.1101/gad.6.7.1332

M3 - Article

C2 - 1321070

SN - 0890-9369

VL - 6

SP - 1332

EP - 1341

JO - Genes and Development

JF - Genes and Development

IS - 7

ER -