ZBTB26

ZBTB26 is a BTB-zinc finger transcription factor that binds specific DNA motifs and shapes active transcriptional programs governing stimulus response, development, and differentiation (PMID:42219880). It executes this role in part by physically recruiting the Integrator auxiliary module through interactions with INTS10 and INTS13, co-occupying promoters and enhancers marked by active histone modifications, where its depletion abolishes Integrator recruitment and disrupts the associated active chromatin states (PMID:42219880). In developmental and disease contexts, ZBTB26 acts upstream of PAX8 to support thyroid anlagen formation in Xenopus (PMID:34946811), transcriptionally regulates ACE in renal carcinoma cells (PMID:39717370), and drives lung squamous cell carcinoma progression by modulating PCNA expression and cell cycle advance (PMID:40168134). Its BTB domain is predicted, by analogy to related ZBTB members whose BTB domains form filamentous assemblies underlying nuclear foci and repression, to support higher-order assembly, though this behavior has been directly demonstrated only for other family members and not ZBTB26 itself (PMID:38996459).

1. 2021 Medium

   Established the first in vivo developmental role for ZBTB26, placing it genetically upstream of the master thyroid factor PAX8.

   Evidence Morpholino knockdown with rescue in Xenopus laevis and marker gene analysis

   PMID:34946811

   Open questions at the time

   • Does not define the direct DNA targets or whether PAX8 regulation is direct
   • Single model organism, single lab
   • Molecular mechanism of transcriptional control not addressed
2. 2024 Medium

   Demonstrated ZBTB26 acts as a direct transcriptional regulator of a defined target gene, ACE, in renal cancer cells.

   Evidence ChIP and luciferase reporter assays in ccRCC cells

   PMID:39717370

   Open questions at the time

   • Cofactors and chromatin context of ACE regulation unknown
   • Whether activation or repression mechanism is used not resolved
   • Single cell-type context
3. 2024 Medium

   Provided structural context for the BTB family, raising the possibility that ZBTB26 forms filamentous higher-order assemblies, but only by prediction.

   Evidence Crystal structures, oligomerization assays, and live-cell foci imaging of related ZBTB members (ZBTB8A, ZBTB18)

   PMID:38996459

   Open questions at the time

   • ZBTB26 filamentation is predicted, not experimentally demonstrated
   • No structure of the ZBTB26 BTB domain
   • Functional consequence of any ZBTB26 assembly untested
4. 2025 Medium

   Connected a smoking-associated regulatory variant to ZBTB26 expression and a downstream cell-cycle effector, defining an oncogenic axis in lung squamous cell carcinoma.

   Evidence Allele-specific FOXA1 binding assay at rs4573350 plus in vitro and xenograft functional assays with PCNA readout

   PMID:40168134

   Open questions at the time

   • Whether ZBTB26 binds and regulates PCNA directly is not established
   • Single lab
   • Generalizability beyond lung SCC unknown
5. 2026 High

   Defined the molecular mechanism of ZBTB26 action: direct DNA binding coupled to recruitment of the Integrator auxiliary module to sustain active chromatin and transcription genome-wide.

   Evidence Reciprocal Co-IP with INTS10/INTS13, DNA-binding assay, ChIP-seq co-occupancy, and depletion with transcriptomic readout

   PMID:42219880

   Open questions at the time

   • Structural basis of the ZBTB26-INTS10/INTS13 interaction not resolved
   • Consensus DNA motif sequence and selectivity not fully characterized
   • Whether developmental and oncogenic roles operate through the Integrator axis untested

• Whether ZBTB26 itself forms BTB-domain filaments and whether its diverse phenotypic roles (thyroid development, ACE regulation, lung tumorigenesis) all funnel through the Integrator-recruitment mechanism remains unresolved.
• No direct demonstration of ZBTB26 self-assembly
• No unifying mechanism linking the context-specific target genes
• Activator vs repressor logic not consolidated across systems