Cell cycle-dependent regulation of RNA polymerase I transcription: the nucleolar transcription factor UBF is inactive in mitosis and early G1
Transcription of ribosomal RNA genes by RNA polymerase (pol) I oscillates during the cell cycle, being maximal in S and G2 phase, repressed during mitosis, and gradually recovering during G1 progression. We have shown that transcription initiation factor (TIF)-IB/SL1 is inactivated during mitosis by...
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| Main Authors: | , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
May 25, 1999
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| In: |
Proceedings of the National Academy of Sciences of the United States of America
Year: 1999, Volume: 96, Issue: 11, Pages: 6096-6101 |
| ISSN: | 1091-6490 |
| DOI: | 10.1073/pnas.96.11.6096 |
| Online Access: | Verlag, Volltext: https://doi.org/10.1073/pnas.96.11.6096 Verlag, Volltext: https://www.pnas.org/content/96/11/6096 
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| Author Notes: | Joachim Klein and Ingrid Grummt |
| Summary: | Transcription of ribosomal RNA genes by RNA polymerase (pol) I oscillates during the cell cycle, being maximal in S and G2 phase, repressed during mitosis, and gradually recovering during G1 progression. We have shown that transcription initiation factor (TIF)-IB/SL1 is inactivated during mitosis by cdc2/cyclin B-directed phosphorylation of TAFI110. In this study, we have monitored reactivation of transcription after exit from mitosis. We demonstrate that the pol I factor UBF is also inactivated by phosphorylation but recovers with different kinetics than TIF-IB/SL1. Whereas TIF-IB/SL1 activity is rapidly regained on entry into G1, UBF is reactivated later in G1, concomitant with the onset of pol I transcription. Repression of pol I transcription in mitosis and early G1 can be reproduced with either extracts from cells synchronized in M or G1 phase or with purified TIF-IB/SL1 and UBF isolated in the presence of phosphatase inhibitors. The results suggest that two basal transcription factors, e.g., TIF-IB/SL1 and UBF, are inactivated at mitosis and reactivated by dephosphorylation at the exit from mitosis and during G1 progression, respectively. |
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| Item Description: | Im Titel ist die "1" bei G1 tiefgestellt Gesehen am 15.02.2021 |
| Physical Description: | Online Resource |
| ISSN: | 1091-6490 |
| DOI: | 10.1073/pnas.96.11.6096 |