UBA2A is a regulator of seed dormancy and DOG1 mRNA chromatin retention in Arabidopsis

Multiple factors control primary seed dormancy established during seed maturation and secondary seed dormancy established when a non-dormant seed is exposed to adverse conditions during imbibition. A key player in the control of both primary and secondary dormancy in Arabidopsis thaliana is the DOG1 gene, whose expression is extensively regulated at the transcriptional level. Despite its importance, the influence of posttranscriptional RNA processing and mRNA storage of DOG1 on the determination of dormancy depth remains elusive. We show that the UBA2A protein, a member of the hnRNP family, suppresses primary and secondary seed dormancy through the regulation of the DOG1 gene expres-sion at the posttranscriptional level. Surprisingly, single-molecule FISH, chromatin-attached RNA analysis and Pol II ChIP demonstrated that UBA2A do not control DOG1 gene transcription but rather DOG1 mRNA chromatin retention. Our study highlights chromatin retention as an important step in DOG1 gene expression regulation during dormancy establishment and shows that UBA2A like its human homolog hnRNPAB is implicated in RNA transport in the cell. Overall design: Comparison of Col-0 and uba2a mutants (uba2a-1 and uba2a-3) dry seed transcriptomes (four biological replicas).