TY  - GEN
N2  - A plants capacity to continuously generate new organs and tissues is fueled by pluripotent stem cells, embedded in specialized niche tissues, called meristems, which provide strict regulation of stem cell fate to balance the need for cell proliferation and cell differentiation. In the Arabidopsis shoot apical meristem (SAM), maintenance of a stable stem cell population largely depends on the non-cell autonomous activity of the homeodomain transcription factor WUSCHEL (WUS).
WUS mRNA is expressed in the organizing center (OC) within the L3 of the shoot meristem. From here, WUS protein moves several cell layers upwards towards the overlying L2 and L1 and into the stem cells in the central zone (CZ). While it has been shown that short-ranged cell-to-cell movement of the WUS protein, via cytoplasmic bridges called plasmodesmata, is essential for WUS function and shoot stem cell maintenance, many aspects of WUS mobility, including its mechanism and regulation, remain unclear or under debate.
Here, I chose a quantitative approach to characterize WUS mobility: For this, I have developed a semi-automated analysis pipeline for layer-specific quantification of fluorescence intensity along the apical-basal axis of the SAM, taking into account meristem curvature. I have then used this analysis in combination with high-resolution live-cell imaging on dissected, unfixed shoot apices to systematically characterize the mobility of differently tagged WUS fusion proteins in complementation lines as well as transcriptionally inactivated mutant alleles in wildtype meristems. From these data, I hypothesize that the mechanism for WUS mobility in the SAM involves a component of active transport that is not directional but regulated via protein retention in the L3. Considering previous studies, my data further indicates that specificity of active WUS movement may be mediated by the WUS homeodomain (HD) and suggests the presence of regulatory sequences not only in the unstructured region between WUS HD and WUS box, but also at the N- and C-terminus.
ID  - heidok31876
Y1  - 2023///
UR  - https://archiv.ub.uni-heidelberg.de/volltextserver/31876/
TI  - Quantitative approaches towards understanding cell-to-cell mobility of the homeodomain transcription factor WUSCHEL (WUS) in the Arabidopsis thaliana shoot apical meristem
CY  - Heidelberg
A1  - Fuchs, Michael
AV  - restricted
ER  -