Homologs of Mitochondrial Transcription Factor B, Sparsely Distributed Within the Eukaryotic Radiation, Are Likely Derived from the Dimethyladenosine Methyltransferase of the Mitochondrial Endosymbiont
Bibliographic record
Abstract
Mitochondrial transcription factor B (mtTFB), an essential component in regulating the expression of mitochondrial DNA-encoded genes in both yeast and humans, is a dimethyladenosine methyltransferase (DMT) that has acquired a secondary role in mitochondrial transcription. So far, mtTFB has only been well studied in Opisthokonta (metazoan animals and fungi). Here we investigate the phylogenetic distribution of mtTFB homologs throughout the domain Eucarya, documenting the first examples of this protein outside of the opisthokonts. Surprisingly, we identified putative mtTFB homologs only in amoebozoan protists and trypanosomatids. Phylogenetic analysis together with conservation of intron positions in amoebozoan and human genes supports the grouping of the putative mtTFB homologs as a distinct clade. Phylogenetic analysis further demonstrates that the mtTFB is most likely derived from the DMT of the mitochondrial endosymbiont.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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 source (direct Gemma or distilled Codex), 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".