Matsuda-Ito, K. | bioRxiv Science

bioRxiv2026

VLCFA-mediated inter-cell layer communication controls cellular pluripotency in Arabidopsis callus

Plants have remarkable capacity to reconstruct entire organ systems from tissue explants. In Arabidopsis two-step tissue culture system, pluripotency regulators are specifically expressed in the middle-cell layer of the stratified callus tissue. However, regulatory mechanisms underlying the radial patterning of callus remained unclear. Here, we found that very-long-chain fatty acids (VLCFAs) synthesized in the epidermis-like outermost layer are essential for pluripotency acquisition and successful shoot regeneration. Our genetic and transcriptomic analyses revealed that the regulatory roles of VLCFAs on pluripotency acquisition involve inter-cell layer signaling in callus tissue, while they are at least partly independent of ATML1/PDF2 functions and cuticular wax synthesis in the outermost layer. VLCFAs spatially restrict procambium cell identity by non-cell-autonomously suppressing cytokinin signaling, thereby allowing for establishment of the middle-cell layer. We propose that the inhibitory relationships between layer-specific regulators underlie the intricate balance of cellular fate determination in pluripotent callus.

plant biology↗

bioRxiv2021

Expression level of the reprogramming factor NeuroD1 is critical for neuronal conversion efficiency from different cell types

Several transcription factors, including NeuroD1, have been shown to act as neuronal reprogramming factors (RFs) that induce neuronal conversion from somatic cells. However, it remains unexplored whether expression levels of RFs in the original cells affect reprogramming efficiency. Here, we show that the neuronal reprogramming efficiency from two distinct glial cell types, microglia and astrocytes, is substantially dependent on the expression level of NeuroD1: low expression failed to induce neuronal reprogramming, whereas elevated NeuroD1 expression dramatically improved reprogramming efficiency in both cell types. Moreover, even under conditions where NeuroD1 expression was too low to induce effective conversion by itself, combined expression of three RFs (Ascl1, Brn2, and NeuroD1) facilitated the breaking down of cellular barriers, inducing neuronal reprogramming. Thus, our results suggest that a sufficiently high expression level of RFs or alternatively their combinatorial expression, is the key to achieving efficient neuronal reprogramming from different cells. Highlights{blacksquare} High expression of NeuroD1 is required for neuronal conversion. {blacksquare}Multiple infections with NeuroD1-expressing virus enhance neuronal reprogramming {blacksquare}Combinatorial expression of NeuroD1 with other RFs facilitates neuronal conversion eTOC blurbIn this article, Matsuda-Ito et al. demonstrate that the efficacy of conversion into neurons from two distinct glial cells, microglia and astrocytes, depends on the NeuroD1 expression level. They also show that increased NeuroD1 expression alone enables efficient neuronal reprogramming in non-reactive astrocytes that were previously shown to be difficult to convert into neurons.

neuroscience↗