Histone Deacetylation Controls Xylem Vessel Cell Differentiation via Transcriptional Regulation of a Transcription Repressor Complex OFP1/4–MYB75–KNAT7–BLH6
Bibliographic record
Abstract
Xylem vessels are indispensable tissues in vascular plants that transport water and minerals. The differentiation of xylem vessel cells is characterized by secondary cell wall deposition and programmed cell death. These processes are initiated by a specific set of transcription factors, called VASCULAR-RELATED NAC-DOMAIN (VND) family proteins, through the direct and/or indirectly induction of genes required for secondary cell wall deposition and programmed cell death. In this study, we explored novel regulatory factors for xylem vessel cell differentiation in Arabidopsis thaliana. We tested the effects of cellular stress inducers on VND7-induced differentiation of xylem vessel cells with the VND7–VP16–GR system, in which VND7 activity is post-translationally induced by dexamethasone application. We established that the histone deacetylase (HDAC) inhibitors trichostatin A (TSA) and sirtinol inhibited VND7-induced xylem vessel cell differentiation. The inhibitory effects of TSA and sirtinol treatment were detected only when they were added at the same time as the dexamethasone application, suggesting that TSA and sirtinol mainly influence the early stages of xylem vessel cell differentiation. Expression analysis revealed that these HDAC inhibitors downregulated VND7-downstream genes, including both direct and indirect targets of transcriptional activation. Notably, the HDAC inhibitors upregulated the transcript levels of negative regulators of xylem vessel cells, OVATE FAMILY PROTEIN1 (OFP1), OFP4, and MYB75, which are known to form a protein complex with BEL1-LIKE HOMEODOMAIN6 (BLH6) to repress gene transcription. The KDB system, another in vitro induction system of ectopic xylem vessel cells, demonstrated that TSA and sirtinol also inhibited ectopic formation of xylem vessel cells, and this inhibition was partially suppressed in knat7-1, bhl6-1, knat7-1 bhl6-1, and quintuple ofp1 ofp2 ofp3 ofp4 ofp5 mutants. Thus, the negative effects of HDAC inhibitors on xylem vessel cell differentiation are mediated, at least partly, by the abnormal upregulation of the transcriptional repressor complex OFP1/4–MYB75–KNAT7–BLH6. Collectively, our findings suggest that active regulation of histone deacetylation by HDACs is involved in xylem vessel cell differentiation via the OFP1/4–MYB75–KNAT7–BLH6 complex.
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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 | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".