Three cyclin‐dependent kinases preferentially phosphorylate different parts of the C‐terminal domain of the large subunit of RNA polymerase II
Bibliographic record
Abstract
The C-terminal domain (CTD) of the largest subunit of RNA polymerase II plays critical roles in the initiation, elongation and processing of primary transcripts. These activities are at least partially regulated by the phosphorylation of the CTD by three cyclin-dependent protein kinases (CDKs), namely CDK7, CDK8 and CDK9. In this study, we systematically compared the phosphorylation of different recombinant CTD substrates by recombinant CDK7/CycH/MAT1, CDK8/CycC and CDK9/CycT1 kinases. We showed that CDK7, CDK8 and CDK9 produce different patterns of phosphorylation of the CTD. CDK7/CycH/MAT1 generates mostly hyperphosphorylated full-length and truncated CTD peptides, while CDK8/CycC and CDK9/CycT1 generate predominantly hypophosphorylated peptides. Total activity towards different parts of the CTD also differs between the three kinases; however, these differences did not correlate with their ability to hyperphosphorylate the substrates. The last 10 repeats of the CTD can act as a suppressor of the activity of the kinases in the context of longer peptides. Our results indicate that the three kinases possess different biochemical properties that could reflect their actions in vivo.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".