Live-cell imaging of RNA Pol II and elongation factors distinguishes competing mechanisms of transcription regulation.
Mol Cell
; 84(15): 2856-2869.e9, 2024 Aug 08.
Article
in En
| MEDLINE
| ID: mdl-39121843
ABSTRACT
RNA polymerase II (RNA Pol II)-mediated transcription is a critical, highly regulated process aided by protein complexes at distinct steps. Here, to investigate RNA Pol II and transcription-factor-binding and dissociation dynamics, we generated endogenous photoactivatable-GFP (PA-GFP) and HaloTag knockins using CRISPR-Cas9, allowing us to track a population of molecules at the induced Hsp70 loci in Drosophila melanogaster polytene chromosomes. We found that early in the heat-shock response, little RNA Pol II and DRB sensitivity-inducing factor (DSIF) are reused for iterative rounds of transcription. Surprisingly, although PAF1 and Spt6 are found throughout the gene body by chromatin immunoprecipitation (ChIP) assays, they show markedly different binding behaviors. Additionally, we found that PAF1 and Spt6 are only recruited after positive transcription elongation factor (P-TEFb)-mediated phosphorylation and RNA Pol II promoter-proximal pause escape. Finally, we observed that PAF1 may be expendable for transcription of highly expressed genes where nucleosome density is low. Thus, our live-cell imaging data provide key constraints to mechanistic models of transcription regulation.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Transcription, Genetic
/
RNA Polymerase II
/
Drosophila Proteins
/
Transcriptional Elongation Factors
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Drosophila melanogaster
Limits:
Animals
Language:
En
Journal:
Mol Cell
Journal subject:
BIOLOGIA MOLECULAR
Year:
2024
Type:
Article
Affiliation country:
United States