HOMEODOMAIN-LIKE shapes chromatin architecture and rewires leaf epidermal patterns [ATACseq]

The mechanisms governing these developmental transitions remain unclear. We identified the homeodomain-like protein HDL, which is required for heterochromatin compaction through interactions with the histone deacetylase HDA6 and the methyltransferase KRYPTONITE during the cell cycle.

Mutants of HDL showed a prolonged interphase, fewer cell divisions, and greater endoreduplication, resulting in fewer stomata and more trichomes. Chromatin immunoprecipitation and ATAC-sequencing revealed higher chromatin accessibility in HDL-bound regions and lower chromatin accessibility along the promoters of stomata-related genes, which also showed reduced expression in hdl mutants. These findings highlight the importance of chromatin organization in maintaining cell division potential and transcriptional control.