Dynamics of TFIIH and Spt4/5 during the transition from transcription initiation to elongation
- 1Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115
- 2Department of Biochemistry, Brandeis University, Waltham, MA 02454
Abstract
The transition of RNA polymerase II from initiation to elongation requires the timely exchange of many factors. Some initiation factors and elongation factors contact the same RNA polymerase II surfaces in an apparently mutually exclusive manner. For example, space occupied by the initiation factor TFIIH and elongation factor Spt4/5 (also known as DSIF) are predicted to overlap. To determine whether Spt4/5 actively displaces TFIIH, or binds only after TFIIH dissociates, labeled yeast nuclear extracts were combined with single-molecule fluorescence microscopy to observe their dynamics in real time. TFIIH categorically dissociates before Spt4/5 arrives, with a clear interval in between with neither factor present. Therefore, Spt4/5 binding is not required to dissociate TFIIH from RNA polymerase II. Significance Statement Proper regulation of eukaryotic gene expression is critical for proper development and response to the environment. Regulation often occurs during the transcription initiation and elongation stages of RNA synthesis. Here we use single-molecule microscopy to image the initiation factor TFIIH and the elongation factor Spt4/5, revealing their relative dynamics and the time-scales of their interactions with RNA polymerase II. We see that TFIIH dissociates before Spt4/5 arrival, indicating that the elongation factor is not required for initiation factor release from the polymerase.
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BibTeX
@article{portman2026dynamics,
title = {{Dynamics of TFIIH and Spt4/5 during the transition from transcription initiation to elongation}},
author = {James R. Portman and Kai Torrens and Gabriela G. Giordano and Jongcheol Jeon and Johnson Chung and Larry J. Friedman and Jeff Gelles and Stephen Buratowski},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
year = {2026},
month = oct,
doi = {10.1073/pnas.2614650123},
url = {https://doi.org/10.1073/pnas.2614650123},
note = {CC BY-NC-ND},
}
RIS
TY - JOUR
TI - Dynamics of TFIIH and Spt4/5 during the transition from transcription initiation to elongation
AU - James R. Portman
AU - Kai Torrens
AU - Gabriela G. Giordano
AU - Jongcheol Jeon
AU - Johnson Chung
AU - Larry J. Friedman
AU - Jeff Gelles
AU - Stephen Buratowski
PY - 2026
DA - 2026/10/28
JO - Proceedings of the National Academy of Sciences of the United States of America
DO - 10.1073/pnas.2614650123
UR - https://doi.org/10.1073/pnas.2614650123
AB - The transition of RNA polymerase II from initiation to elongation requires the timely exchange of many factors. Some initiation factors and elongation factors contact the same RNA polymerase II surfaces in an apparently mutually exclusive manner. For example, space occupied by the initiation factor TFIIH and elongation factor Spt4/5 (also known as DSIF) are predicted to overlap. To determine whether Spt4/5 actively displaces TFIIH, or binds only after TFIIH dissociates, labeled yeast nuclear extracts were combined with single-molecule fluorescence microscopy to observe their dynamics in real time. TFIIH categorically dissociates before Spt4/5 arrives, with a clear interval in between with neither factor present. Therefore, Spt4/5 binding is not required to dissociate TFIIH from RNA polymerase II. Significance Statement Proper regulation of eukaryotic gene expression is critical for proper development and response to the environment. Regulation often occurs during the transcription initiation and elongation stages of RNA synthesis. Here we use single-molecule microscopy to image the initiation factor TFIIH and the elongation factor Spt4/5, revealing their relative dynamics and the time-scales of their interactions with RNA polymerase II. We see that TFIIH dissociates before Spt4/5 arrival, indicating that the elongation factor is not required for initiation factor release from the polymerase.
SN - 0027-8424
SN - 1091-6490
ER -