# Research timeline and gaps: Chromatin Accessibility = Transcriptional Competence

Selected publication milestones, not an exhaustive history or discovery priority claim.

**2008 — 2008:local upstream ncRNA transcription is required for fbp1 chromatin opening in fission yeast, demonstrating a reverse-direction route.** [Original PMID18820678](https://pubmed.ncbi.nlm.nih.gov/18820678/).

**2015 — 2015:targeted p300 acetyltransferase activates endogenous genes; artificial acetylation/coactivator recruitment is separated from opening alone.** [Original PMID25849900](https://pubmed.ncbi.nlm.nih.gov/25849900/).

**2017 — 2017:OCT4 requires BRG1 for selected regulatory-element function in mouseESCs, mapping pioneer/remodeler cooperation.** [Original PMID28287392](https://pubmed.ncbi.nlm.nih.gov/28287392/).

**2019 — 2019:repli-ATAC and transcription inhibition show transcription restart contributes to postreplication accessibility restoration.** [Original PMID31126739](https://pubmed.ncbi.nlm.nih.gov/31126739/).

**2020 — 2020:early zebrafish opening precedes activation and largely survives transcription inhibition, with miR430 as an exception.** [Original PMID31940339](https://pubmed.ncbi.nlm.nih.gov/31940339/).

**2021 — 2021:acute BAF degradation/ATPase inhibition identifies minute-scale accessibility maintenance; early transcription effects and tag baselines require separate interpretation.** [Original PMID33558760](https://pubmed.ncbi.nlm.nih.gov/33558760/).

**2022 — 2022:targeted active/dead HAT contrasts show opening alone can fail to activate an endogenous target during ZGA.** [Original PMID35182480](https://pubmed.ncbi.nlm.nih.gov/35182480/).

**2023 — 2023:EP400 compensation restores many promoter states/outputs; paused-polymerase/BAF work published2024(PMID38049663) strengthens bidirectional cooperation.** [Original PMID37922899](https://pubmed.ncbi.nlm.nih.gov/37922899/).

**2025 — 2025:BRG1 dose manipulation shows enhancer sensitivity and buffered transcription, refining a simple one-to-one access model.** [Original PMID40846763](https://pubmed.ncbi.nlm.nih.gov/40846763/).

**2026 — 2026:single-fiber nucleosome-distortion and factor-domain experiments refine the physical meaning of molecular DNA access.** [Original PMID42056506](https://pubmed.ncbi.nlm.nih.gov/42056506/).

## Research gaps

A selective accessible-state necessity intervention must preserve the multifunctional regulators that establish it.

Competence requires a standardized activating challenge and cannot be inferred from either basal ATAC or basal RNA alone.

Bulk ATAC/DNase, methylase footprinting, local nucleosome distortion and large-scale decondensation measure different aspects of access.

Temporal direction depends on developmental, replication and stimulus context; a universal upstream or downstream account fails.

Specificity of factor/remodeler perturbations must exclude cell-cycle, viability, replication stress and transcriptional-collapse alternatives at each sampled time.

Opening-only sufficiency fails at named loci, while acetylation/coactivator rescue can work; these need independent locus/state replication.

Preprint/update duplication, shared reagents and repeated loci must be distinguished from independent error classes.

## Boundary experiment

At prespecified native promoters/enhancers, alter DNA accessibility with an orthogonal state intervention while preserving factor occupancy, activation domains, acetylation/coactivators and polymerase function as far as possible. Apply a matched activating stimulus and measure initiation/bursting with calibrated nascent RNA and single-fiber accessibility. Restore only the accessible state in a matched rescue; retain a dead-HAT opening-without-activation control. Verify cell-cycle distribution, replication stress, viability, target-factor abundance and local cis sequence across developmental/replication windows.