Faculty Opinions recommendation of SCARECROW is involved in positioning the stem cell niche in the Arabidopsis root meristem.

Author(s):  
Philip Benfey
2019 ◽  
Vol 225 (3) ◽  
pp. 1261-1272
Author(s):  
Diego Ornelas‐Ayala ◽  
Rosario Vega‐León ◽  
Emilio Petrone‐Mendoza ◽  
Adriana Garay‐Arroyo ◽  
Berenice García‐Ponce ◽  
...  

2018 ◽  
Author(s):  
Ramin Rahni ◽  
Kenneth D. Birnbaum

AbstractCharacterizing the behaviors of dynamic systems requires capturing them with high temporal and spatial resolution. Owing to its transparency and genetic tractability, theArabidopsis thalianaroot lends itself well to live imaging when combined with cell and tissue-specific fluorescent reporters. We developed a novel 4D imaging method that utilizes simple confocal microscopy and readily available components to track cell divisions in the root stem cell niche and surrounding region for up to one week. This new setup allows us to finely analyze meristematic cell division rates that lead to patterning. Using this method, we performed a direct measurement of cell division intervals within and around the root stem cell niche. The results reveal a short, steep gradient of cell division in proximal stem cells, with progressively more rapid cell division rates from QC, to cells in direct contact with the QC (initials), to their immediate daughters, after which division rates appear to become more homogeneous. These results provide a baseline to study how perturbations in signaling could affect cell division patterns in the root meristem.


2021 ◽  
Author(s):  
Josep Mercadal ◽  
Isabel Betegón-Putze ◽  
Nadja Bosch ◽  
Ana I. Caño-Delgado ◽  
Marta Ibañes

AbstractStem cell niches are local microenvironments that preserve their unique identity while communicating with adjacent tissues. In the primary root of Arabidopsis thaliana, the stem cell niche comprises the expression of two transcription factors, BRAVO and WOX5, among others. Intriguingly, these proteins confine their own gene expression to the niche, as evidenced in each mutant background. Here we propose through mathematical modeling that BRAVO confines its own expression domain to the stem cell niche by attenuating its WOX5-dependent diffusible activator. This negative feedback drives WOX5 action to be spatially restricted as well. The results show that WOX5 diffusion and sequestration by binding to BRAVO is sufficient to drive realistic confined BRAVO expression at the stem cell niche. We propose that attenuation of a diffusible activator can be a general mechanism to confine genetic activity to a small region while at the same time maintain signaling within it and with the surrounding cells.


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