Dataset: lhp1 FLC-Venus time course imaging – Hybrid protein assembly-histone modification mechanism for PRC2-based epigenetic switching and memory

The histone modification H3K27me3 plays a central role in Polycomb-mediated epigenetic silencing. H3K27me3 recruits and allosterically activates Polycomb Repressive Complex 2 (PRC2), which adds this modification to nearby histones, providing a read/write mechanism for inheritance through DNA replication. However, for some PRC2 targets, a purely histone-based system for epigenetic inheritance may be insufficient. We address this issue at the Polycomb target Flowering Locus C (FLC) in Arabidopsis thaliana, as a narrow nucleation region of only ~three nucleosomes within FLC mediates epigenetic state switching and subsequent memory over many cell cycles. To explain the memory’s unexpected persistence, we introduce a mathematical model incorporating extra protein memory storage elements with positive feedback that persist at the locus through DNA replication, in addition to histone modifications. Our hybrid model explains many features of epigenetic switching/memory at FLC and encapsulates generic mechanisms that may be widely applicable.

Methods
Raw images of the FLC-Venus protein levels in Arabidopsis thaliana roots of the lhp1 mutant.

Plants were grown in ambient temperatures for 7 days, vernalized for 10 weeks and returned to ambient temperatures for respective time (for methods see https://doi.org/10.7554/eLife.66454)

Images are bundled in lif files per experimental day and labelled in the following way: 

e.g. 20200120_10W_T14

20200120 refers to day the images were taken [here on the 20th of January 2020]

10W refers to the growth period in the cold (vernalization) [here 10 weeks]

T14 refers to the growth period after cold (post-vernalization) [here 14 days]

subname: SDB995-5 refers to John Innes Centre internal seed batch number.

T0 was included to show cold-induced autofluorescence.

For imaging details and processing see: https://doi.org/10.7554/eLife.66454