A conserved function of corepressors is to nucleate assembly of the transcriptional preinitiation complex

Abstract

The plant corepressor TPL is recruited to diverse chromatin contexts, yet its mechanism of repression remains unclear. Previously, we have leveraged the fact that TPL retains its function in a synthetic transcriptional circuit in the yeast model Saccharomyces cerevisiae to localize repressive function to two distinct domains. Here, we employed two unbiased whole genome approaches to map the physical and genetic interactions of TPL at a repressed locus. We identified SPT4, SPT5 and SPT6 as necessary for repression with the SPT4 subunit acting as a bridge connecting TPL to SPT5 and SPT6. We also discovered the association of multiple additional constituents of the transcriptional preinitiation complex at TPL-repressed promoters, specifically those involved in early transcription initiation events. These findings were validated in yeast and plants through multiple assays, including a novel method to analyze conditional loss of function of essential genes in plants. Our findings support a model where TPL nucleates preassembly of the transcription activation machinery to facilitate rapid onset of transcription once repression is relieved.

A history-dependent integrase recorder of plant gene expression with single cell resolution

“…In theory, our recorder designs should be transferable to any plant that can be transformed, for applications such as those facilitating evo-devo studies of key developmental processes such as stomata.Our recorder can be applied in plants which undergo different paths of stomatal development, such as in amphibious plants which largely skip the SPCH -driven, asymmetrical cell divisions 55 and grasses which have a completely different arrangement of subsidiary cells compared to Arabidopsis 56 . In addition, integrase switches can be adapted to allow study of essential genes in non-essential organs 57 . Porting this system into crop plants could enable optimization and quantification of traits associated with climate resilience, facilitating marker-assisted breeding efforts.…”