The Chromatin-Associated Protein PWO1 Interacts with Plant Nuclear Lamin-like Components to Regulate Nuclear Size

Abstract

Spatial organization of chromatin contributes to gene regulation of many cellular processes and includes a connection of chromatin with the nuclear lamina (NL). The NL is a protein mesh that resides underneath the inner nuclear membrane and consists of lamins and lamina-associated proteins. Chromatin regions associated with lamins in animals are characterized mostly by constitutive heterochromatin, but association with facultative heterochromatin mediated by Polycomb-group (PcG) proteins has been reported as well. In contrast with animals, plant NL components are largely not conserved and NL association with chromatin is poorly explored. Here, we present the connection between the lamin-like protein, CROWDED NUCLEI1 (CRWN1), and the chromatin-and PcG-associated component, PROLINE-TRYPTOPHANE-TRYPTOPHANE-PROLINE INTERACTOR OF POLYCOMBS1, in Arabidopsis (Arabidopsis thaliana). We show that PWO1 and CRWN1 proteins associate physically with each other, act in the same pathway to maintain nuclear morphology, and control expression of a similar set of target genes. Moreover, we demonstrate that transiently expressed PWO1 proteins form foci located partially at the subnuclear periphery. Ultimately, as CRWN1 and PWO1 are plant-specific, our results argue that plants might have developed an equivalent, rather than homologous, mechanism of linking chromatin repression and NL.

A lamin‐like protein OsNMCP1 regulates drought resistance and root growth through chromatin accessibility modulation by interacting with a chromatin remodeller OsSWI3C in rice

“…CRWN genes play vital roles in plant immunity; because a crwn1 crwn2 double mutant is more resistant to virulent pathogens than wild‐type (WT) plants (Guo et al , 2017). CRWN1 also interacts with chromatin protein to regulate gene expression (Mikulski et al , 2019) and plays a critical role in modulating chromatin positioning patterns as a key component of the plant lamina–chromatin network (Hu et al , 2019).…”

Mitotic Inheritance of PRC2-Mediated Silencing: Mechanistic Insights and Developmental Perspectives

“…H3K27me3-marked chromatin domains have been shown to form foci in the nucleus of mammalian cells . Similarly, in plant interphasic nuclei, PRC2 is enriched in nuclear speckles containing PWWP-DOMAIN INTERACTOR OF POLYCOMBS1 (PWO1), a factor that interacts with lamin-like proteins (Mikulski et al, 2019). Although their presence in replicating cells remains to be formally established, such PRC2-enriched microenvironments could participate in maintaining PRC2 close to its targets during the passage of the fork.…”

Chromatin domains in space and their functional implications

“…For instance, the silencing of NAD-genes might be due to preventing RNA polymerase II from being associated with the nucleolus [43]. On the other hand, the plant lamin protein CRWN1 was shown to interact with PWWP INTERACTOR OF POLYCOMBS 1 (PWO1), which associated with Polycomb-group proteins, suggesting the involvement of H3K27me3mediated transcriptional repression in LADs [44]. At the moment, research of plant LADs and NADs are still at an infant stage, as the knowledge of proteins required for forming these chromatin domains is extremely limited.…”